334 Sentences With "basilar" | Random Sentence Generator

McCabe&aposs doctors later determined he had suffered a stroke as a result of a blood clot to his basilar artery, located at the front of the brain stem.

A soft tissue structure called the basilar membrane, while not present in the fossil itself, was indicated by other parts of the ear to be of a size and thickness consistent with high-frequency hearing.

The cerebellum helps with voluntary processes such as posture, balance, coordination and speech," according to Health Line , which explained that "interruption of the blood flow through the basilar artery can lead to severe brain damage, organ malfunction, or even death.

Basilar skull fractures are often associated with instantaneous fatalities and, in the case of race car driving, are caused by the driver's head continuing forward after their body is restrained by the series of belts and straps constraining their torso.

The apparatus is "a carbon-fiber and Kevlar collar with two tethers that connect to the driver's helmet" designed to secure the driver's head and prevent it from moving independently of their body, thus reducing the risk of basilar skull fracture.

If you want to be able to listen to that song not just then but also five years from now, you're going to want to make sure your basilar membrane remains healthy (that's the thing in your ear that lets you hear).

Though the 49-year-old was not pronounced dead until he arrived at the Halifax Medical Center — the same hospital where Newman was transported after his crash 19 years later — his autopsy revealed a basilar skull fracture as the cause of death.

Petty is a father to daughter Montgomery Lee Petty, 32, and sons Austin Petty, 35, and Adam Petty, a professional racing driver who died at age 19 in May 2000 after suffering a basilar skull fracture from a crash during his practice run for the Busch 200 race that year.

The basilar sulcus (groove for basilar artery) is a groove in the pons, part of the brainstem. The basilar sulcus is vertical directed and lies in the midline of the pons on its anterior (front) surface. The basilar artery runs within the basilar sulcus. The basilar sulcus is bounded on either side by an eminence caused by the descent of the cerebrospinal fibers through the substance of the pons.

Migraine with brainstem aura (abbreviated MBA) (previously used terms: basilar artery migraine; basilar migraine; basilar-type migraine) is a subtype of migraine with aura in which symptoms clearly originate from the brainstem, but no motor weakness. When motor symptoms are present, the subtype is coded as 1.2.3 Hemiplegic migraine. Originally the terms basilar artery migraine or basilar migraine were used but, since involvement of the basilar artery is unlikely, the term migraine with brainstem aura is preferred in ICHD-3 beta.

The basilar crest gives attachment to the outer edge of the basilar membrane; immediately above the crest is a concavity, the sulcus spiralis externus.

The basilar plexus (transverse or basilar sinus) consists of several interlacing venous channels between the layers of the dura mater over the basilar part of the occipital bone (the clivus), and serves to connect the two inferior petrosal sinuses. It communicates with the anterior vertebral venous plexus.

Human brainstem blood supply description. Basilar artery is #7, and pons is visible below it. Medial pontine syndrome results from occlusion of paramedian branches of the basilar artery.

The basilar part of pons, also known as basis pontis, is the ventral part of the pons; the dorsal part is known as the pontine tegmentum. The basilar pons makes up two thirds of the pons within the brainstem. It has a ridged appearance with a shallow groove at the midline This groove is called the basilar sulcus and is covered by the basilar artery, which feeds into the Circle of Willis and provides blood supply to the brainstem and cerebellum. The basilar pons has this kind of appearance due to the fibers that come out of the pons and enter the cerebellum.

The basilar membrane is a stiff structural element within the cochlea of the inner ear which separates two liquid-filled tubes that run along the coil of the cochlea, the scala media and the scala tympani. The basilar membrane moves up and down in response to incoming sound waves, which are converted to traveling waves on the basilar membrane.

Only about 19% of adults retain PCommA dominance of the PCA with 72% having dominant basilar origin, and the rest having either equal prominence between PCommA and basilar artery, or a single exclusive source.

Basal or basilar is a term meaning base, bottom, or minimum.

The basilar crest lies within the cochlear duct in the inner ear. It gives attachment to the outer edge of the basilar membrane and is a spiral ligament that projects inward below as a triangular prominence.

There are many different qualities in sound stimuli including loudness, pitch and timbre. The human ear is able to detect differences in pitch through the movement of auditory hair cells found on the basilar membrane. High frequency sounds will stimulate the auditory hair cells at the base of the basilar membrane while medium frequency sounds cause vibrations of auditory hair cells located at the middle of the basilar membrane. For frequencies that are lower than 200 Hz, the tip of the basilar membrane vibrates in sync with the sound waves.

In a 'normal' ear the auditory filter has a shape similar to the one shown below. This graph reflects the frequency selectivity and the tuning of the basilar membrane. The auditory filter of a "normal" cochlea The tuning of the basilar membrane is due to its mechanical structure. At the base of the basilar membrane it is narrow and stiff and is most responsive to high frequencies.

Sounds consist of waves of air molecules that vibrate at different frequencies. These waves travel to the basilar membrane in the cochlea of the inner ear. Different frequencies of sound will cause vibrations in different location of the basilar membrane. We are able to hear different pitches because each sound wave with a unique frequency is correlated to a different location along the basilar membrane.

Wiener, F.(1947), "On the diffraction of a progressive wave by the human head". Journal of the Acoustical Society of America, 19, 143-146. As the organ of hearing, the cochlea consists of two membranes, Reissner’s and the basilar membrane. The basilar membrane moves to audio stimuli through the specific stimulus frequency matches the resonant frequency of a particular region of the basilar membrane.

The pontine tegmentum, or dorsal pons, is located within the brainstem, and is one of two parts of the pons, the other being the ventral pons or basilar part of the pons. The pontine tegmentum can be defined in contrast to the basilar pons: basilar pons contains the corticospinal tract running craniocaudally and can be considered the rostral extension of the ventral medulla oblongata; however, basilar pons is distinguished from ventral medulla oblongata in that it contains additional transverse pontine fibres that continue laterally to become the middle cerebellar peduncle. The pontine tegmentum is all the material dorsal from the basilar pons to the fourth ventricle. Along with the dorsal surface of the medulla, it forms part of the rhomboid fossa – the floor of the fourth ventricle.

The basal pontine nuclei provides the most information to the cerebellum. These pontine nuclei are integral in helping the basilar pons carry information from the cerebral cortex to the cerebellum. The basilar pons is able to do this via the corticopontine fibers that it receives. Once the information passes from the cerebral cortex to the basilar pons and then finally to the cerebellum, the cerebellum gets information regarding complex cognitive functions.

The structure evolved from the basilar papilla and is crucial for mechanotransduction in mammals.

The second mechanism is a non-linear active mechanism, which is primarily dependent on the functioning of the OHCs, and also the general physiological condition of the cochlea itself. The base and apex of the basilar membrane differ in stiffness and width, which cause the basilar membrane to respond to varying frequencies differently along its length. The base of the basilar membrane is narrow and stiff, resulting in it responding best to high frequency sounds. The apex of the basilar membrane is wider and much less stiff in comparison to the base, causing it to respond best to low frequencies.

The superior cerebellar artery (SCA) arises near the termination of the basilar artery.Refer to diagrams.

Figure 4: Neural tuning curve for normal hearing. The traveling wave along the basilar membrane peaks at different places along it, depending on whether the sound is low or high frequency. Due to the mass and stiffness of the basilar membrane, low frequency waves peak in the apex, while high frequency sounds peak in the basal end of the cochlea. Therefore, each position along the basilar membrane is finely tuned to a particular frequency.

These specifically tuned frequencies are referred to as characteristic frequencies (CF). If a sound entering the ear is displaced from the characteristic frequency, then the strength of response from the basilar membrane will progressively lessen. The fine tuning of the basilar membrane is created by the input of two separate mechanisms. The first mechanism being a linear passive mechanism, which is dependent on the mechanical structure of the basilar membrane and its surrounding structures.

The basilar region is not actually small, but it is inferior in size to the sincipital.

Hearing Research, 17(3), 237–247. doi: 10.1016/0378-5955(85)90068-1 The temporal lobes of the owls were then removed from the skulls, post-fixed in 1% osmium tetroxide, dehydrated, then embedded in Araldite to study the anatomy of the inner ear. This study revealed that the basilar papilla of barn owls has two very unique features being a proliferation of lenticular cells and a thickening of the basilar membrane. The cochlear duct of the owl contains the basilar papilla, the tectorial membrane, the tegmentum vasculum, and the macula of the lagena. The basilar papilla of the cochlea was measured to be 9.5-11.5 mm long.

The vestibular surface of the basilar membrane is covered by supporting cells and a few border cells at the inferior edge of the membrane. The basilar membrane is relatively thin toward the distal end of the papilla, but has a thick fibrous mass toward the proximal end. This dense fibrous mass measured to be about 37-57 µm in width and 8.5-11 µm in thickness among the owls utilized for this study. This mass is not to be confused with the loose fibrous mass of the tympanic part of the basilar membrane that underlies the part of the basilar membrane that is covered by sensory cells.

The basilar membrane is also the base for the hair cells. This function is present in all land vertebrates. Due to its location, the basilar membrane places the hair cells adjacent to both the endolymph and the perilymph, which is a precondition of hair cell function.

The basilar membrane stretches from the tympanic lip of the osseous spiral lamina to the basilar crest and consists of two parts, an inner and an outer. The inner is thin, and is named the inner tunnel (or zona arcuata): it supports the spiral organ of Corti.

Effecting a differential diagnosis between basilar migraine and hemiplegic migraine is difficult. Often, the decisive symptom is either motor weakness or unilateral paralysis, which occur in FHM and SHM. Basilar migraine can present tingling and numbness, but true motor weakness and paralysis occur only in hemiplegic migraine.

The movement of the basilar membrane causes hair cell stereocilia movement. The hair cells are attached to the basilar membrane, and with the moving of the basilar membrane, the tectorial membrane and the hair cells are also moving, with the stereocilia bending with the relative motion of the tectorial membrane. This can cause opening and closing of the mechanically gated potassium channels on the cilia of the hair cell. The cilia of the hair cell are in the endolymph.

The cochlea is a spiral-shaped, fluid-filled tube divided lengthwise by the organ of Corti which contains the basilar membrane. The basilar membrane increases in thickness as it travels through the cochlea causing different frequencies to resonate at different locations. This tonotopic design allows for the ear to analyze sound in a manner similar to a Fourier transform. The differential vibration of the basilar causes the hair cells within the organ of Corti to move.

The lower frequencies were detected when the basilar membrane was stimulated, providing even further evidence for rate coding.

Unlike models based on a series of active filters or represented with digital equations, an analog ear can incorporate nonlinearities that represent nonlinear actions of the basilar membrane, perhaps caused by asymmetric motions of sensory cells resulting in asymmetric motions of the basilar membrane. Difference frequencies could be generated as are observed in the human. Some difference frequencies originating in the cochlea can be observed in the outer ear. Neural signals responding to motions of the basilar membrane show responses in one direction as in rectification.

The scala vestibuli and scala media are separated by Reissner's Membrane whereas the scala media and scala tympani are divided by the basilar membrane. The diagram below illustrates the complex layout of the compartments and their divisions: Cross-section through the cochlea, showing the different compartments (as described above) The basilar membrane widens as it progresses from base to apex. Therefore, the base (the thinnest part) has a greater stiffness than the apex. This means that the amplitude of a sound wave travelling through the basilar membrane varies as it travels through the cochlea.

The basilar membrane is a pseudo-resonant structure that, like the strings on an instrument, varies in width and stiffness. But unlike the parallel strings of a guitar, the basilar membrane is a single structure with different width, stiffness, mass, damping, and duct dimensions at different points along its length. The motion of the basilar membrane is generally described as a traveling wave. The properties of the membrane at a given point along its length determine its characteristic frequency (CF), the frequency at which it is most sensitive to sound vibrations.

Surgery for basilar impressions can be carried out if pressure being exerted on the spinal cord and brain stem is causing neurological problems.

The placement of vibration on the cochlea depends upon the frequency of the presented stimuli. For example, lower frequencies mostly stimulate the apex, in comparison to higher frequencies, which stimulate the base of the cochlea. This attribute of the physiology of the basilar membrane can be illustrated in the form of a place–frequency map: Simplified schematic of the basilar membrane, showing the change in characteristic frequency from base to apex The basilar membrane supports the organ of Corti, which sits within the scala media. The organ of Corti comprises both outer and inner hair cells.

A third, evolutionarily younger, function of the basilar membrane is strongly developed in the cochlea of most mammalian species and weakly developed in some bird species: Fritzsch B: The water-to-land transition: Evolution of the tetrapod basilar papilla; middle ear, and auditory nuclei. In: the dispersion of incoming sound waves to separate frequencies spatially. In brief, the membrane is tapered and it is stiffer at one end than at the other. Furthermore, sound waves travelling to the "floppier" end of the basilar membrane have to travel through a longer fluid column than sound waves travelling to the nearer, stiffer end.

The development of the PCA in fetal brain comes relatively late and arises from the fusion of several embryonic vessels near the caudal end of the PCommA supplying the mesencephalon and diencephalon of the fetus. The PCA begins as such, as a continuation of the PCommA in the fetus with only 10–30% of fetuses having a prominent basilar origin. The fetal carotid origin of the PCA usually regresses as the vertebral and basilar arteries develop with the PCommA reducing is size. In most adults, the PCA sources from the anterior portion of the basilar artery.

In birds, crocodilians, and monotremes, the ducts are simply extended, together forming an elongated, more or less straight, tube. The endolymphatic duct is wrapped in a simple loop around the lagena, with the basilar membrane lying along one side. The first half of the duct is now referred to as the scala vestibuli, while the second half, which includes the basilar membrane, is called the scala tympani. As a result of this increase in length, the basilar membrane and papilla are both extended, with the latter developing into the organ of Corti, while the lagena is now called the cochlear duct.

Georg von Békésy (, ; born in Budapest, Hungary on 3 June 1899 – 13 June 1972) was a Hungarian biophysicist. By using strobe photography and silver flakes as a marker, he was able to observe that the basilar membrane moves like a surface wave when stimulated by sound. Because of the structure of the cochlea and the basilar membrane, different frequencies of sound cause the maximum amplitudes of the waves to occur at different places on the basilar membrane along the coil of the cochlea. High frequencies cause more vibration at the base of the cochlea while low frequencies create more vibration at the apex.

Békésy contributed most notably to our understanding of the mechanism by which sound frequencies are registered in the inner ear. He developed a method for dissecting the inner ear of human cadavers while leaving the cochlea partly intact. By using strobe photography and silver flakes as a marker, he was able to observe that the basilar membrane moves like a surface wave when stimulated by sound. Because of the structure of the cochlea and the basilar membrane, different frequencies of sound cause the maximum amplitudes of the waves to occur at different places on the basilar membrane along the coil of the cochlea.

However, both the somatic motor and the hair bundle motor produce significant displacements of the basilar membrane. This, in turn, leads to augmentation of bundle movement and signal amplification. The mechanical force that is generated by these mechanisms increases the movement of the basilar membrane. This, in turn, influences the deflection of the hair bundles of the inner hair cells.

They do this by receiving mechanical signals or vibrations along the basilar membrane, and transducing them into electrochemical signals. The stereocilia found on OHCs are in contact with the tectorial membrane. Therefore, when the basilar membrane moves due to vibrations, the stereocilia bend. The direction in which they bend, dictates the firing rate of the auditory neurons connected to the OHCs.

The active process is also known as the cochlear amplifier. This amplification increases vibrations of the basilar membrane through energy obtained from the Organ of Corti. As the stimulation increases, it is assumed that basilar membrane displacement, caused by the traveling wave, becomes continually more basal in regards to the cochlea.McFadden D, Plattsmier H. Exposure-induced loudness shifts and threshold shifts.

Distinct layers of basilar and non-basilar crest cells were identified within the deep MON. Drawing a comparison to similar cells in the closely related electrosensory lateral line lobe of electric fish, it seems to suggest possible computational pathways of the MON. The MON is likely involved in the integration of sophisticated excitatory and inhibitory parallel circuits in order to interpret mechanoreceptive information.

The basilar artery () is one of the arteries that supplies the brain with oxygen-rich blood. The two vertebral arteries and the basilar artery are sometimes together called the vertebrobasilar system, which supplies blood to the posterior part of the circle of Willis and joins with blood supplied to the anterior part of the circle of Willis from the internal carotid arteries.

The movement the basilar membrane displaces the inner hair cells in one direction, which encodes a half-wave rectified signal of action potentials in the spiral ganglion cells. The axons of these cells make up the auditory nerve, encoding the rectified stimulus. The auditory nerve responses select certain frequencies, similar to the basilar membrane. For lower frequencies, the fibers exhibit "phase locking".

Diagnostic criteria require motor symptoms and at least one visual, sensory, or speech symptom, resembling basilar migraine. They may also be associated with cerebellar signs.

In birds and crocodilians, the similarity of the structure of the basilar papilla betrays their close evolutionary relationship. The basilar papilla is up to about 10mm long and contains up to 16,500 hair cells. While most birds have an upper hearing limit of only about 6 kHz, the barn owl can hear up to 12 kHz and thus close to the human upper limit.

Fig. 1: Dolichoectasia of the suprasellar segment of the left internal carotid artery with compression of the optic chiasm Most commonly affected are the vertebral and basilar arteries (Vertebral Basilar Dolichoectasia or Vertebrobasillar Dolichoectasia). The internal carotid artery may also be affected. Patients with Autosomal Dominant Polycystic Kidney Disease (ADPKD) are more likely to be subject to dolichoectasias. Dolichoectasias are most common in elderly males.

The latter is referred to as Bone Conduction (or BC) hearing, as complementary to the first one described, which is instead called Air Conduction (or AC) hearing. Both AC and BC stimulate the basilar membrane in the same way (Békésy, G.v., Experiments in Hearing. 1960). The basilar membrane on the tympanic duct presses against the hair cells of the organ as perilymphatic pressure waves pass.

The development of the posterior cerebral artery (PCA) in the fetal brain occurs relatively late and arises from the fusion of several embryonic vessels near the caudal end of the posterior communicating artery. The PCA begins as a continuation of the posterior communicating artery in 70-90% of fetuses with the remainder of PCAs having a basilar origin. The fetal carotid origin of the PCA usually regresses as the vertebral and basilar arteries become dominant and it finds a new origin in the basilar artery. About 20% of adults retain PCA origin from the posterior communicating artery, and in turn, the internal carotid arteries.

In 2010 Seely was diagnosed with Chiari II malformation, basilar invagination, and Ehlers-Danlos syndrome. In August, 2013, her left leg was amputated below the knee.

In this way, the patterns of oscillations on the basilar membrane are converted to spatiotemporal patterns of firings which transmit information about the sound to the brainstem.

"Skull fractures. Step-by-step diagnostic approach". Best Practice, BMJ. If bilateral, it is highly suggestive of basilar skull fracture, with a positive predictive value of 85%.

Dallos, P., D.Z.Z. He, I. Sziklai, X. Lin, S. Mehta and B.N. Evans, Acetylcholine, outer hair cell electromotility, and the cochlear amplifier, J. Neurosci. 15: 2212-2226 (1997). [2.10] Invention and development of the hemicochlea technique and intracellular recordings from hair cells in the hemicochlea under basilar membrane stimulation Richter, C.-P., B.N. Evans, R. Edge and P. Dallos, Basilar membrane vibrations in the gerbil hemicochlea, J. Neurophysiol.

The cochlear duct is bounded on three sides by the basilar membrane, the stria vascularis, and Reissner's membrane. Stria vascularis is a rich bed of capillaries and secretory cells; Reissner's membrane is a thin membrane that separates endolymph from perilymph; and the basilar membrane is a mechanically somewhat stiff membrane, supporting the receptor organ for hearing, the organ of Corti, and determines the mechanical wave propagation properties of the cochlear system.

Bronchial geotrichosis shows peribronchial thickening with fine mottling may be present on middle or basilar pulmonary fields. Bronchial geotrichosis usually present itself as non-specific diffuse peribronchical infiltration.

The tympanic duct or scala tympani is one of the perilymph-filled cavities in the inner ear of the human. It is separated from the cochlear duct by the basilar membrane, and it extends from the round window to the helicotrema, where it continues as vestibular duct. The purpose of the perilymph-filled tympanic duct and vestibular duct is to transduce the movement of air that causes the tympanic membrane and the ossicles to vibrate, to movement of liquid and the basilar membrane. This movement is conveyed to the organ of Corti inside the cochlear duct, composed of hair cells attached to the basilar membrane and their stereocilia embedded in the tectorial membrane.

The foramen lacerum () is a triangular hole in the base of skull, located between the sphenoid, the apex of the petrous temporal and the basilar part of the occipital.

Along with the vestibular membrane, several tissues held by the basilar membrane segregate the fluids of the endolymph and perilymph, such as the inner and outer sulcus cells (shown in yellow) and the reticular lamina of the organ of Corti (shown in magenta). For the organ of Corti, the basilar membrane is permeable to perilymph. Here the border between endolymph and perilymph occurs at the reticular lamina, the endolymph side of the organ of Corti.

Each side enters the cranial cavity through the foramen magnum along the corresponding side of the medulla. They give off one of the three cerebellar branches. The vertebral arteries join in front of the middle part of the medulla to form the larger basilar artery, which sends multiple branches to supply the medulla and pons, and the two other anterior and superior cerebellar branches. Finally, the basilar artery divides into two posterior cerebral arteries.

Models for the ear of a direct kind have been created, most notably by Nobel Laureate Georg von Békésy. He used glass slides, razor blades, and an elastic membrane to represent the helicotrema. He could measure vibrations along the basilar membrane in response to different excitations frequencies. He found that the pattern of displacements for given frequency sine wave along the basilar membrane rose somewhat gradually to a peak and thereafter fell.

From there, the two channels are represented with a sequence of inductors and resistors for fluid flow within each channel with the two channels joined with a sequence of series resonant RLC circuits. Voltages across capacitances represent basilar membrane displacements. Element values along the cochlea are tapered in a logarithmic fashion to represent lowering frequency responses with distance. The pattern of voltages along the basilar membrane can be viewed on an oscilloscope.

Therefore, in response to the electrical stimulations provided by the efferent nerve supply, they can alter in length, shape and stiffness. These changes influence the response of the basilar membrane to sound. It is therefore clear that the OHCs play a major role in the active processes of the cochlea. The main function of the active mechanism is to finely tune the basilar membrane, and provide it with a high sensitivity to quiet sounds.

There are three to four times as many OHCs as IHCs. The basilar membrane (BM) is a barrier between scalae, along the edge of which the IHCs and OHCs sit. Basilar membrane width and stiffness vary to control the frequencies best sensed by the IHC. At the cochlear base the BM is at its narrowest and most stiff (high-frequencies), while at the cochlear apex it is at its widest and least stiff (low- frequencies).

Intracranial aneurysm, also known as brain aneurysm, is a cerebrovascular disorder in which weakness in the wall of a cerebral artery or vein causes a localized dilation or ballooning of the blood vessel. Aneurysms in the posterior circulation (basilar artery, vertebral arteries and posterior communicating artery) have a higher risk of rupture. Basilar artery aneurysms represent only 3–5% of all intracranial aneurysms but are the most common aneurysms in the posterior circulation.

There are some examples of pitch which do not have an "edge" on the basilar membrane, which this would account for—e.g., white noise, clicks, etc. Both theories are under debate.

Odontocetes (toothed whales and dolphins) have similar cochlear specializations to those found in bats. Odontocetes also have the highest neural investment of any cochleae reported to date with ratios of greater than 1500 ganglion cells/mm of basilar membrane. Further along the auditory pathway, the movement of the basilar membrane results in the stimulation of primary auditory neurons. Many of these neurons are specifically "tuned" (respond most strongly) to the narrow frequency range of returning echoes of CF calls.

In the mammalian cochlea, wave amplification occurs via the outer hair cells of the organ of Corti. These cells sit directly above a basilar membrane (BM) that has high sensitivity for differences in frequency. Sound waves enter the scala vestibuli of the cochlea and travel throughout it, carrying with them various sound frequencies. These waves exert a pressure on the basilar and tectorial membranes of the cochlea which vibrate in response to sound waves of different frequencies.

The basilar membrane is tonotopic, so that each frequency has a characteristic place of resonance along it. Characteristic frequencies are high at the basal entrance to the cochlea, and low at the apex. Basilar membrane motion causes depolarization of the hair cells, specialized auditory receptors located within the organ of Corti. While the hair cells do not produce action potentials themselves, they release neurotransmitter at synapses with the fibers of the auditory nerve, which does produce action potentials.

The lagena is separated from the perilymphatic duct by a basilar membrane, and contains the sensory hair cells that finally translate the vibrations in the fluid into nerve signals. It is attached at one end to the saccule. In most reptiles the perilymphatic duct and lagena are relatively short, and the sensory cells are confined to a small basilar papilla lying between them. However, in birds, mammals, and crocodilians, these structures become much larger and somewhat more complicated.

This stiffness is due to, among other things, the thickness and width of the basilar membrane,Camhi, J. Neuroethology: nerve cells and the natural behavior of animals. Sinauer Associates, 1984. which along the length of the cochlea is stiffest nearest its beginning at the oval window, where the stapes introduces the vibrations coming from the eardrum. Since its stiffness is high there, it allows only high-frequency vibrations to move the basilar membrane, and thus the hair cells.

As the basilar membrane vibrates, each clump of hair cells along its length is deflected in time with the sound components as filtered by basilar membrane tuning for its position. The more intense this vibration is, the more the hair cells are deflected and the more likely they are to cause cochlear nerve firings. Temporal theory supposes that the consistent timing patterns, whether at high or low average firing rate, code for a consistent pitch percept.

The pontine arteries are a number of small vessels which come off at right angles from either side of the basilar artery and supply the pons and adjacent parts of the brain.

In the membrane of the outer hair cells there are motor proteins associated with the membrane. Those proteins are activated by sound-induced receptor potentials as the basilar membrane moves up and down. These motor proteins can amplify the movement, causing the basilar membrane to move a little bit more, amplifying the traveling wave. Consequently, the inner hair cells get more displacement of their cilia and move a little bit more and get more information than they would in a passive cochlea.

Edwin Robert Bickerstaff (20 November 1920 – 23 November 2008), was a British neurologist. He is best remembered for describing Bickerstaff's encephalitis and a subtype of migraine (basilar migraine) that is sometimes called "Bickerstaff's migraine".

The movement of the basilar membrane compared to the tectorial membrane causes the stereocilia to bend. They then depolarise and send impulses to the brain via the cochlear nerve. This produces the sensation of sound.

He was pronounced there dead upon arrival. The official cause of death was basilar skull fracture. Villeneuve Curva, the location of Ratzenberger's fatal crash. Ayrton Senna was killed the next day at the bend before.

As the basilar membrane moves upward, the cilia move in the direction causing opening of the mechanically gated potassium channel. The influx of potassium ions leads to depolarization. On the contrary, the cilia move the other way as the basilar membrane moves down, closing more mechanically gated potassium channels and leading to hyperpolarization. Depolarization will open the voltage gated calcium channel, releasing neurotransmitter (glutamate) at the nerve ending, acting on the spiral ganglion cell, the primary auditory neurons, making them more likely to spike.

The hair bundle motor is the force generated from a mechanical stimulus. This is done through the use of the mechanoelectrical transduction (MET) channel, which allows for the passage of Na+, K+, and Ca2+. The hair bundle motor operates by deflecting hair bundles in the positive direction and providing positive feedback of the basilar membrane, increasing the movement of the basilar membrane which increases the response to a signal. Two mechanisms have been proposed for this motor: fast adaptation, or channel re-closure, and slow adaptation.

Pioneered by Georg von Békésy, a method to observe the basilar membrane in action came about in the mid 1900s. Békésy isolated the cochlea from human and animal cadavers and labeled the basilar membrane with silver flakes. This allowed strobe imaging to capture the movement of the membrane as sounds stimulated the hair cells. This led to the solidification of the idea that high frequencies excite the basal end of the cochlea and provided new information that low frequencies excite a large area of the cochlea.

While intracranial artery stenting is used for same side stroke prevention, basilar artery stenting may help to improve parallel, accessory blood flow. The stent may also lead to termination of recurrent middle cerebral artery (MCA) strokes.

Thus diagnosis of extraparenchymal cysts usually relies on signs like hydrocephalus or enhanced basilar meninges. In such cases CT scan with intraventricular contrast or MRI can be used. MRI is more sensitive in detection of intraventricular cysts.

The subalar and basilar muscles have ligament attachments to the subalar and basilar sclerites. Here resilin, a highly elastic material, forms the ligaments connecting flight muscles to the wing apparatus. In more derived orders of insects, such as Diptera (flies) and Hymenoptera (wasp), the indirect muscles occupy the greatest volume of the pterothorax and function as the primary source of power for the wingstroke. Contraction of the dorsolongitudinal muscles causes the severe arching of the notum which depresses the wing while contraction of the dorsoventral muscles causes opposite motion of notum.

This part of the brainstem contains fibers from the corticospinal tract (a descending pathway for neurons to reach other structures in the body), pontine nuclei, and transverse pontine fibers. The corticospinal tract carries neurons from the primary motor cortex in the brain to the spinal cord, aiding in voluntary motor movement of the body. In addition to passing through the basilar pons, corticospinal tract fibers go through other structures of the brainstem, such as the internal capsule and the crus cerebri. An integral part of the basilar pons is the pontine nuclei.

Dead regions can be defined in terms of the characteristic frequencies of the IHC, related to the specific place along the basilar membrane where the dead region occurs. Assuming that there has been no shift in the characteristic frequencies relating to certain regions of the basilar membrane, due to the damage of OHCs. This often occurs with IHC damage. Dead regions can also be defined by the anatomical place of the non-functioning IHC (such as an “apical dead region”), or by the characteristic frequencies of the IHC adjacent to the dead region.

Peduncular hallucinosis is attributed to a range of various pathologies such as vascular and infectious midbrain, pontine and thalamic lesions, local subarachnoid hemorrhage, compression by tumors, basilar migraine, basilar vascular hypoplasia, and following regional surgical or angiographic interventions. These pathologies are mainly near the base of the brain and the hallucinations have gone away in patients that had their pathology corrected such as the removal of a tumor. The most commonly reported hallucinations are animals, people of any age, scary or deformed faces and heads, landscapes, or people walking in a line.

This spatial arrangement of sounds and their respective frequencies being processed in the basilar membrane is known as tonotopy. When the hair cells on the basilar membrane move back and forth due to the vibrating sound waves, they release neurotransmitters and cause action potentials to occur down the auditory nerve. The auditory nerve then leads to several layers of synapses at numerous clusters of neurons, or nuclei, in the auditory brainstem. These nuclei are also tonotopically organized, and the process of achieving this tonotopy after the cochlea is not well understood.

At the midpoint of an oscillation the hair bundles resume their resting position. When the basilar membrane moves downward, the hair bundles are driven in the inhibitory direction. Basilar Membrane motion causes a shearing motion between the reticular lamina and the tectorial membrane, thereby activating the mechano-sensory apparatus of the hair bundle, which in turn generates a receptor potential in the hair cells. Thus the sound pressure wave is transduced to an electrical signal which can be processed as sound in higher parts of the auditory system.

The basilar papilla is the auditory sensory organ of lizards, amphibians, and birds, which is analogous to the organ of Corti in mammals. The basilar papilla is composed of cells called "hair cells" which are actually epithelial cells rather than true hairs. These sensory cells, according to some studies, are related to the type II sensory cells in the vestibular epithelium of mammals. These auditory hair cells, unlike those in mammals, are known to spontaneously regenerate following injury, with experimental evidence showing that this ability to proliferate is mediated by a micro-RNA called miR181a.

Sound waves enter the outer ear and travel through the external auditory canal until they reach the tympanic membrane, causing the membrane and the attached chain of auditory ossicles to vibrate. The motion of the stapes against the oval window sets up waves in the fluids of the cochlea, causing the basilar membrane to vibrate. This stimulates the sensory cells of the organ of Corti, atop the basilar membrane, to send nerve impulses to the central auditory processing areas of the brain, the auditory cortex, where sound is perceived and interpreted.

Furosemide injections prior to noise exposure have been shown to decrease the endocochlear potential.Ruggero M, Rich N. Furosemide alters organ of corti mechanics: evidence for feedback of outer hair cells upon the basilar membrane. J Neurosci. 1991;11:1057 - 1067.

Amplification to these sounds is therefore required, in order for the basilar membrane to respond efficiently. IHCs are less susceptible to damage in comparison to the OHCs. However, if they become damaged, this will result in an overall loss of sensitivity.

Duret hemorrhage – small brainstem hemorrhage due to rupture of the paramedian basilar artery branches resulting from brainstem distortion secondary to transtentorial herniation. Duret lesion – small hemorrhage(s) in the floor of the fourth ventricle or beneath the aqueduct of Sylvius.

While antibiotics are frequently used in an attempt to prevent meningitis in those with a basilar skull fracture there is not enough evidence to determine whether this is beneficial or harmful. This applies to those with or without a CSF leak.

When a vibration is carried through the cochlea, the fluid within the three compartments causes the basilar membrane to respond in a wave-like manner. This wave is referred to as a 'travelling wave'; this term means that the basilar membrane does not simply vibrate as one unit from the base towards the apex. When a sound is presented to the human ear, the time taken for the wave to travel through the cochlea is only 5 milliseconds. When low-frequency travelling waves pass through the cochlea, the wave increases in amplitude gradually, then decays almost immediately.

Thresholds at low frequency dead regions, are more inaccurate than those at higher frequency dead regions. This has been attributed to the fact that excitation due to vibration of the basilar membrane spreads upwards from the apical regions of the basilar membrane, more than excitation spreads downwards from higher frequency basal regions of the cochlea. This pattern of the spread of excitation is similar to the ‘upward spread of masking’ phenomenon. If the tone is sufficiently loud to produce enough excitation at the normally functioning area of the cochlea, so that it is above that areas threshold.

As the first stage of CASA processing, the cochleagram creates a time-frequency representation of the input signal. By mimicking the components of the outer and middle ear, the signal is broken up into different frequencies that are naturally selected by the cochlea and hair cells. Because of the frequency selectivity of the basilar membrane, a filter bank is used to model the membrane, with each filter associated with a specific point on the basilar membrane. Since the hair cells produce spike patterns, each filter of the model should also produce a similar spike in the impulse response.

The pharyngeal aponeurosis (or pharyngobasilar fascia, or fibrous coat), is situated between the mucous and muscular layers. It is thick above where the muscular fibers are wanting, and is firmly connected to the basilar portion of the occipital and the petrous portions of the temporal bones. As it descends it diminishes in thickness, and is gradually lost. It is strengthened posteriorly by a strong fibrous band, which is attached above to the pharyngeal spine on the under surface of the basilar portion of the occipital bone, and passes downward, forming a median raphé, which gives attachment to the Constrictores pharyngis.

56(2): p. 136-8Tubbs, R., et al., The basilar venous plexus. Clinical Anatomy, 2007. 20(7)De Wyngaert, R., I. Casteels, and P. Demaerel, Orbital and anterior visual pathway infection and inflammation. Neuroradiology, 2009. 51(6): p. 385-96Jost, G., et al.

The cochlear duct (or scala media) is an endolymph filled cavity inside the cochlea, located between the tympanic duct and the vestibular duct, separated by the basilar membrane and Reissner's membrane (the vestibular membrane) respectively. The cochlear duct houses the organ of Corti.

For methodological reasons, most research on isolated mammalian brains has been done with guinea pigs. These animals have a significantly larger basilar artery (a major artery of the brain) compared to rats and mice, which makes cannulation (to supply CSF) much easier.

The posterior surface, quadrilateral in form [Fig. 3], is joined, during infancy and adolescence, to the basilar part of the occipital bone by a plate of cartilage. Between the eighteenth and twenty-fifth years this becomes ossified, ossification commencing above and extending downward.

Structure of the Barn Owls (Tyto alba) Inner Ear. Hearing Research, 17(3), 237–247. doi: 10.1016/0378-5955(85)90068-1 Two major parts that construct the basilar membrane of the barn owl include the vestibular part and the tympanic part.

Angiogram demonstrating persistent trigeminal artery, as indicated by the black arrow. The trigeminal artery is an artery that supplies the basilar artery with blood during human embryonic development.Simon J. Dimmick and Kenneth C. Faulder. "Normal Variants of the Cerebral Circulation at Multidetector CT Angiography".

The inner ear is supplied by the anterior tympanic branch of the maxillary artery; the stylomastoid branch of the posterior auricular artery; the petrosal branch of middle meningeal artery; and the labyrinthine artery, arising from either the anterior inferior cerebellar artery or the basilar artery.

Cranial nerves X, XI, and XII leave lateral wall of opisthotic through a single foramen. No canal in basioccipital or basispehnoid for basilar artery. Suprastapedial process of quadrate moderately large, distally pointed. Dorsal edge of surangular rounded and longitudinally horizontal...Twenty nine presacral vertebrae present.

The common carotid artery divides into the internal and the external carotid arteries. The internal carotid artery becomes the anterior cerebral artery and the middle central artery. The ACA transmits blood to the frontal parietal. From the basilar artery are two posterior cerebral arteries.

The labyrinthine artery (auditory artery, internal auditory artery) is a branch of the anterior inferior cerebellar artery (85–100% cases) or basilar artery (<15% cases). It accompanies the vestibulocochlear nerve through the internal acoustic meatus, and supplies blood to the internal ear.Refer to diagram.

The anterior inferior cerebellar artery (AICA) is one of three pairs of arteries that supplies blood to the cerebellum. It arises from the basilar artery on each side at the level of the junction between the medulla oblongata and the pons in the brainstem. It has a variable course, passing backward to be distributed to the anterior part of the undersurface of the cerebellum, anastomosing with both the posterior inferior cerebellar (PICA) branch of the vertebral artery and the superior cerebellar artery. It also gives off the internal auditory or labyrinthine artery in most cases; however, the labyrinthine artery can less commonly emerge as a branch of the basilar artery.

In medicine, the dense artery sign or hyperdense artery sign is an increased radiodensity of an artery as seen on computer tomography (CT) scans, and is a radiologic sign of early ischemic stroke. In earlier studies of medical imaging in patients with strokes, it was the earliest sign of ischemic stroke in a significant minority of cases. Its appearance portends a poor prognosis for the patient. The sign has been observed in the middle cerebral artery (MCA), posterior cerebral artery (PCA), vertebral artery, and basilar artery; these have been called the dense MCA sign, dense PCA sign, dense vertebral artery sign, and dense basilar artery sign, respectively.

Police violence was reported in connection with the protests. Police officers used batons and pepper spray injuring activists so intensely that they had to be treated in hospitals. The injuries included a basilar skull fracture. The police said they would take the allegations seriously and investigate accordingly.

Amphibians have unique inner ear structures. There are two sensory papillae involved in hearing, the basilar (higher frequency) and amphibian (lower frequency) papillae, but it is uncertain whether either is homologous to the hearing organs of lepidosaurs, archosaurs and mammals and we have no idea when they arose.

The foramen lacerum () is a triangular hole in the base of skull located between the sphenoid, apex of petrous temporal and basilar part of occipital. It is the juncture of the petroclival, sphenopetrosal, and pterygosphenoidal sutures. The foramen lacerum is a foramen situated anteromedial to the carotid canal.

Echolocation clicks also contain characteristic details unique to each animal, which may suggest that toothed whales can discern between their own click and that of others. Mysticeti have exceptionally thin, wide basilar membranes in their cochleae without stiffening agents, making their ears adapted for processing low to infrasonic frequencies.

The cochlea thus acts as an 'acoustic prism', distributing the energy of each Fourier component of a complex sound at different locations along its longitudinal axis. Hair cells in the cochlea are stimulated when the basilar membrane is driven up and down by differences in the fluid pressure between the scala vestibuli and scala tympani. Because this motion is accompanied by a shearing motion between the tectorial membrane and the reticular lamina of the organ of Corti, the hair bundles that link the two are deflected, which initiates mechano-electrical transduction. When the basilar membrane is driven upward, shear between the hair cells and the tectorial membrane deflects hair bundles in the excitatory direction, toward their tall edge.

The organ of Corti is also capable of modulating the auditory signal. The outer hair cells (OHCs) can amplify the signal through a process called electromotility where they increase movement of the basilar and tectorial membranes and therefore increase deflection of stereocilia in the IHCs. A crucial piece to this cochlear amplification is the motor protein prestin, which changes shape based on the voltage potential inside of the hair cell. When the cell is depolarized, prestin shortens, and because it is located on the membrane of OHCs it then pulls on the basilar membrane and increasing how much the membrane is deflected, creating a more intense effect on the inner hair cells (IHCs).

The vibrations of the endolymph in the cochlear duct displace the basilar membrane in a pattern that peaks a distance from the oval window depending upon the soundwave frequency. The organ of Corti vibrates due to outer hair cells further amplifying these vibrations. Inner hair cells are then displaced by the vibrations in the fluid, and depolarise by an influx of K+ via their tip- link-connected channels, and send their signals via neurotransmitter to the primary auditory neurons of the spiral ganglion. The hair cells in the organ of Corti are tuned to certain sound frequencies by way of their location in the cochlea, due to the degree of stiffness in the basilar membrane.

The basilar membrane is widest (0.42–0.65 mm) and least stiff at the apex of the cochlea, and narrowest (0.08–0.16 mm) and stiffest at the base (near the round and oval windows). High-frequency sounds localize near the base of the cochlea, while low-frequency sounds localize near the apex.

On the way out through the aorta the gas may be entrained in blood flowing into the carotid or basilar arteries. If these bubbles cause blockage in blood vessels, this is arterial gas embolism. Sufficient pressure difference and expansion to cause this injury can occur from depths as shallow as .

This may succeed or accompany temporal lobe (uncal) herniation and subfalcian herniation secondary to a supratentorial mass. The pathophysiological mechanism is uncertain but is probably caused by the displacement of the brainstem stretching and tearing perforating branches of the basilar artery to the pons; venous infarction may play a role.

He found that movement of the basilar membrane resembles that of a traveling wave; the shape of which varies based on the frequency of the pitch. In low-frequency sounds, the tip (apex) of the membrane moves the most, while in high-frequency sounds, the base of the membrane moves most.

The apex, rough and uneven, is received into the angular interval between the posterior border of the great wing of the sphenoid bone and the basilar part of the occipital bone; it presents the anterior or internal opening of the carotid canal, and forms the postero-lateral boundary of the foramen lacerum.

As the VIth nerve passes through the subarachnoid space it lies adjacent to anterior inferior and posterior inferior cerebellar and basilar arteries and is therefore vulnerable to compression against the clivus. Typically palsies caused in this way will be associated with signs and symptoms of headache and/or a rise in ICP.

The squamosal wing to the parietal is large. There is a deep groove present in the floor of the basioccipital for the basilar artery. The suprastapedial process is fused to the infrastapedial process on the quadrate and the tympanic ala are thick. The stapedial pit is nearly circular to elliptical in form.

While the basic structure of the inner ear in lepidosaurs (lizards and snakes), archosaurs (birds and crocodilians) and mammals is similar, and the organs are considered to be homologous, each group has a unique type of auditory organ. The hearing organ arose within the lagenar duct of stem reptiles, lying between the saccular and lagenar epithelia. In lepidosaurs, the hearing organ, the basilar papilla, is generally small, with at most 2000 hair cells, whereas in archosaurs the basilar papilla can be much longer (>10mm in owls) and contain many more hair cells that show two typical size extremes, the short and the tall hair cells. In mammals, the structure is known as the organ of Corti and shows a unique arrangement of hair cells and supporting cells.

Figure 8: Response of the basilar membrane to a pure tone, when there is a dead region. However, it appears that this is not the case. Dead regions cannot be clearly found via PTA audiograms. This may be because although the neurons innervating the dead region, cannot react to vibration at their characteristic frequency.

The pharyngeal tubercle is a part of the occipital bone of the head and neck. It is located on the lower surface of the basilar part of occipital bone, about 1 cm. anterior to the foramen magnum. The pharyngeal tubercle gives attachment to the fibrous raphe of the pharynx, also known as the pharyngeal raphe.

The simple tones of an instrument are called harmonics or overtones. Timbre is created by putting the harmonics together with the fundamental frequency (a sound's basic pitch). When a complex sound is heard, it causes different parts in the basilar membrane to become simultaneously stimulated and flex. In this way, different timbres can be distinguished.

Organ pipes were often used in early hearing experiments. Due to the invasiveness of most hearing related experiments, it is difficult to use human models in the study of the auditory system. However, many findings have been revealed in cats and guinea pigs. Additionally, there are few ways to study the basilar membrane in vivo.

The relationship of the spiral turns of the cochela and the length of the basilar membrane to the range of audible frequencies in ground dwelling mammals. Journal of the Acoustical Society of America 77:1091-1101.EA Lipman and JR Grassi. 1942. Comparative auditory sensitivity of man and dog. Amer J Psychol 55:84-89.

These leverage the larger motions of the eardrum to the smaller vibrations of the oval window. This window connects to the cochlea which is a long dual channel arrangement consisting of two channels separated by the basilar membrane. The structure, about 36 mm in length, is coiled to conserve space. The oval window introduces sounds to the upper channel.

Rodríguez was killed instantly by a basilar skull fracture caused by the impact with the wall, which was lined by only a thin layer of tires. Because of the incident, an additional tire wall was installed at the end of the straight. Rodríguez had a contract in place to compete in the 2000 CART championship with Patrick Racing.

In patients with normal chest radiographs, prone scans have been found useful in 17% of cases, particularly in excluding posterior lung abnormalities. In patients with abnormal findings on chest radiographs, prone scans are only useful in 4% of cases. The scans may be more useful in patients with basilar predominant disease processes, such as asbestosis and idiopathic pulmonary fibrosis.

Neural adaptations for processing the two-note call of the Puerto Rican treefrog, Eleutherodactylus coqui. Brain, Behavior and Evolution, 17:48-66. Since the "Qui" note is a wide-band signal that sweeps upward in frequency, it appears as though the fibers innervating the female basilar papilla are better suited for detection of this component of the call.

The collicular artery originates from P1 segment of the posterior cerebral artery near the side of interpeduncular fossa. It arises just distal to the bifurcation of the basilar artery. It runs posteriorly along the cerebral peduncle passing the crural and ambient cisterns. It then gives off branches to supply quadrigeminal plate and the adjacent structures in the midbrain.

The trigeminal artery arises from the primitive internal carotid artery during development, when the embryo is approximately 6 weeks old. The trigeminal artery then anastomoses with the basilar artery. At this point in development, the trigeminal artery serves as the main blood supply for the hindbrain, as other vessels in the region have yet to mature.William S. Fields.

Both the scala vestibuli and the scala tympani contain an extracellular fluid called perilymph. The scala media contains endolymph. A set of membranes called the vestibular membrane and the basilar membrane develop to separate the cochlear duct from the vestibular duct and the tympanic duct, respectively. Parts of the otic vesicle in turn form the vestibulocochlear nerve.

The inner ear consists of the cochlea and several non- auditory structures. The cochlea has three fluid-filled sections (i.e. the scala media, scala tympani and scala vestibuli), and supports a fluid wave driven by pressure across the basilar membrane separating two of the sections. Strikingly, one section, called the cochlear duct or scala media, contains endolymph.

Diagnosis is confirmed via biopsy of the tissue(s) suspected to be affected by SCC. For the skin, look under skin biopsy. The pathological appearance of a squamous cell cancer varies with the depth of the biopsy. For that reason, a biopsy including the subcutaneous tissue and basilar epithelium, to the surface is necessary for correct diagnosis.

Discharge from the ear can be caused by acute otitis media with perforation of the eardrum, chronic suppurative otitis media, tympanostomy tube otorrhea, or acute otitis externa. Trauma, such as a basilar skull fracture, can also lead to cerebrospinal fluid otorrhea (discharge of CSF from the ear) due to cerebral spinal drainage from the brain and its covering (meninges).

Basilar invagination is invagination (infolding) of the base of the skull that occurs when the top of the C2 vertebra migrates upward. It can cause narrowing of the foramen magnum (the opening in the skull where the spinal cord passes through to the brain). It also may press on the lower brainstem. This is similar to Chiari malformation.

The strawberry anemone grows no larger than 2.5 centimeters. The anemone can be red, pink, purple, brown, yellow, or completely white. They possess tentacles that are white or transparent with bulbous tips. The strawberry anemone resembles sea anemones in that they lack a calcareous skeleton, but are closer related to stony corals in that they lack basilar muscles.

The farther a wave travels towards the cochlea's apex (the helicotrema), the less stiff the basilar membrane is; thus lower frequencies travel down the tube, and the less-stiff membrane is moved most easily by them where the reduced stiffness allows: that is, as the basilar membrane gets less and less stiff, waves slow down and it responds better to lower frequencies. In addition, in mammals, the cochlea is coiled, which has been shown to enhance low-frequency vibrations as they travel through the fluid-filled coil. This spatial arrangement of sound reception is referred to as tonotopy. For very low frequencies (below 20 Hz), the waves propagate along the complete route of the cochlea – differentially up vestibular duct and tympanic duct all the way to the helicotrema.

This is because the frequency selectivity and the tuning of the basilar membrane is reduced as the outer hair cells are damaged. When only the outer hair cells are damaged the filter is broader on the low frequency side. When both the outer and inner hair cells are damaged the filter is broader on both sides. This is less common.

The lower channel has a round window but this is not driven by the bones of the middle ear. The far end of the structure has a hole between the two channels called the helicotrema that equalizes slowly varying pressures in the two channels. A series of sensory hair cells along the basilar membrane respond to send neural pulses towards the brain.

Posterior to the clivus is the basilar artery. The pons sits on the clivus. Clivus is also used as an abbreviated term for the clivus ocularis which is the sloping inner wall of the retina as it dips into the foveola in the macula of the eye. For this reason, and to disambiguate, the clivus is sometimes referred to as the Blumenbach clivus.

Battle's sign takes at least one day to appear after the initial traumatic basilar skull fracture, similar to raccoon eyes.Handbook of Signs & Symptoms (Third Edition) It is usually seen after head injuries resulting in injury to mastoid process leading to bruising. Battle's sign may be confused with a spreading hematoma from a fracture of the mandibular condyle, which is a less serious injury.

Algorithm for extraction of pitch and pitch salience from complex tonal signals. Journal of the Acoustical Society of America, 71(3), 679-688. pitch perception can be divided into two separate stages: auditory spectral analysis and harmonic pitch pattern recognition. In the first stage, the inner ear (cochlea and basilar membrane) performs a running spectral analysis of the incoming signal.

No canal or groove in floor of basioccipital or basisphenoid for basilar artery. Suprastapedial process of quadrate distally expanded. Dorsal edge of surangular thin lamina of bone rising anteriorly to posterior surface of coronoid...At least 31, usually 42–45 presacral vertebrae present. Length of presacral series exceeds that of postsacral, neural spines of posterior caudal vertebrae elongated to form distinct fin.

As a venous sinus, the cavernous sinus receives blood from the superior and inferior ophthalmic veins and from superficial cortical veins, and is connected to the basilar plexus of veins posteriorly. The cavernous sinus drains by two larger channels, the superior and inferior petrosal sinuses, ultimately into the internal jugular vein via the sigmoid sinus, also draining with emissary vein to pterygoid plexus.

In addition, triptans should be prescribed with caution for those with risk factors for vascular disease. While historically not recommended in those with basilar migraines there is no specific evidence of harm from their use in this population to support this caution. They are not addictive, but may cause medication-overuse headaches if used more than 10 days per month.

During practice for the thatlook.com 300 at New Hampshire Motor Speedway on July 7, 2000, Irwin slammed head on into the wall, causing his car to flip onto its side. According to fellow driver Brett Bodine speaking to CNN, the car slid along its side for a long time before rolling on its roof. Irwin likely died instantly of a basilar skull fracture.

The pathophysiology of Kyrle disease is unclear. Some scientists believe that it may be a variation of prurigo nodularis. The theory that most scientists agree upon is that Kyrle disease is an elimination of keratin and other cellular material across the epidermis. Keratinization in Kyrle disease form at the basilar layer that is lower than the normal proliferation region in the epidermis.

Boettcher cells are a special cell type located in the inner ear. Boettcher cells are polyhedral cells on the basilar membrane of the cochlea, and are located beneath Claudius cells. Boettcher cells are considered supporting cells for the organ of Corti, and are present only in the lower turn of the cochlea. These cells interweave with each other, and project microvilli into the intercellular space.

The posterior cerebral artery (PCA) is one of a pair of arteries that supply oxygenated blood to the occipital lobe, part of the back of the human brain. The two arteries originate from the distal end of the basilar artery, where it bifurcates into the left and right posterior cerebral arteries. These anastomose with the middle cerebral arteries and internal carotid arteries via the posterior communicating arteries.

She is also active in films, mainly used for short but often effective character roles. In 1991 Leone suffered a congenital aneurysm of the basilar artery, undergoing a complicated surgery in Phoenix, Arizona which had a mortality rate of 80%. She was paralyzed on the left side of the body but was able to recover completely. She eventually went back to work after a long absence.

SOC, in the pons of the brainstem, travel along the lateral lemniscus to the IC, located in the midbrain. Signals are then relayed to the thalamus and further ascending auditory pathway. As sound travels into the inner eardrum of vertebrate mammals, it encounters the hair cells that line the basilar membrane of the cochlea in the inner ear. The cochlea receives auditory information to be binaurally integrated.

Within the cochlea, the hair cells on the sensory epithelium of the organ of Corti bend and cause movement of the basilar membrane. The membrane undulates in different sized waves according to the frequency of the sound. Hair cells are then able to convert this movement (mechanical energy) into electrical signals (graded receptor potentials) which travel along auditory nerves to hearing centres in the brain.Eatock, R. (2010).

The vertebral arteries are major arteries of the neck. Typically, the vertebral arteries originate from the subclavian arteries. Each vessel courses superiorly along each side of the neck, merging within the skull to form the single, midline basilar artery. As the supplying component of the vertebrobasilar vascular system, the vertebral arteries supply blood to the upper spinal cord, brainstem, cerebellum, and posterior part of brain.

Birds have an auditory system similar to that of mammals, including a cochlea. Reptiles, amphibians, and fish do not have cochleas but hear with simpler auditory organs or vestibular organs, which generally detect lower- frequency sounds than the cochlea. The cochlea of birds is similar to that of crocodiles, consisting of a short, slightly curved bony tube within which lies the basilar membrane with its sensory structures.

Lera Boroditsky. (1999) "Hearing I: Lecture Notes." pp. 3 Békésy concluded from these observations that by exciting different locations on the basilar membrane different sound wave frequencies excite different nerve fibers that lead from the cochlea to the brain. He theorized that, due to its placement along the cochlea, each sensory cell (hair cell) responds maximally to a specific frequency of sound (the so-called tonotopy).

Canal or deep groove in floor of basioccipital and basispehnoid for basilar artery. Suprastapedial process of quadrate large, bluntly terminated and with parallel sides. Dorsal edge of surangular rounded and longitudinally horizontal...Twenty-nine or less presacral vertebrae present. Length of presacral series less than that of postsacral, neural spines of posterior caudal vertebrae at most only slightly elongated, do not form an appreciable fin.

Paranasal sinuses When exceptionally large the sphenoid sinuses may extend into the roots of the pterygoid processes or great wings, and may invade the basilar part of the occipital bone. Each sinus opens into the roof of the nasal cavity via apertures on the posterior wall of the sphenoethmoidal recess directly above the choana. The apertures are located high on the anterior walls of the sinuses themselves.

A major advantage of performing an endoscopic third ventriculostomy over placement of a cerebrospinal fluid shunt is the absence of an implanted foreign body. A shunt has risk of infection and failure for which subsequent surgery is needed. Complications of ETV include hemorrhage (the most severe being due to basilar artery rupture), injury to neural structures (e.g. hypothalamus, pituitary gland or fornix of the brain), and late sudden deterioration.

Figure 3: Cross- section of the cochlea. Outer hair cells (OHCs) contribute to the structure of the Organ of Corti, which is situated between the basilar membrane and the tectorial membrane within the cochlea (See Figure 3). The tunnel of corti, which runs through the Organ of Corti, divides the OHCs and the inner hair cells (IHCs). OHCs are connected to the reticular laminar and the Deiters’ cells.

If the basilar membrane vibration is large enough, neurons tuned to different characteristic frequencies such as those adjacent to the dead region, will be stimulated due to the spread of excitation. Therefore, a response from the patient at the test frequency will be obtained. This is referred to as “off- place listening”, and is also known as ‘off-frequency listening’. This will lead to a false threshold being found.

The round window is one of the two openings from the middle ear into the inner ear. It is sealed by the secondary tympanic membrane (round window membrane), which vibrates with opposite phase to vibrations entering the inner ear through the oval window. It allows fluid in the cochlea to move, which in turn ensures that hair cells of the basilar membrane will be stimulated and that audition will occur.

The inner ear is a small but very complex organ. The inner ear consists of the cochlea, which is a spiral-shaped, fluid-filled tube. It is divided lengthwise by the organ of Corti, which is the main organ of mechanical to neural transduction. Inside the organ of Corti is the basilar membrane, a structure that vibrates when waves from the middle ear propagate through the cochlear fluid – endolymph.

Figure 7: The three major arteries of the cerebellum: the SCA, AICA, and PICA Figure 8: Illustration showing regions supplied by the three cerebellar arteries. Three arteries supply blood to the cerebellum (Fig. 7): the superior cerebellar artery (SCA), anterior inferior cerebellar artery (AICA), and posterior inferior cerebellar artery (PICA). The SCA branches off the lateral portion of the basilar artery, just inferior to its bifurcation into the posterior cerebral artery.

Attempts to revive Earnhardt failed and his death was officially pronounced at 5:16 p.m. EST (22:16 UTC); he was 49 years old. The official cause of Earnhardt's death was given by the Volusia County medical examiner's office as blunt force trauma to his head among other injuries due to the incident.CNNSI.com: Earnhardt autopsy report answers, leaves questions He also sustained a fatal basilar skull fracture on impact.

Eletriptan was approved by the US Food and Drug Administration (FDA) on December 26, 2002, for the acute treatment of migraine with or without aura in adults.FDA AccessData entry for Eletriptan Hydrobromide, accessed March 10, 2010. It is available only by prescription in the United States and Canada. It is not intended for the prophylactic therapy of migraine or for use in the management of hemiplegic or basilar migraine.

The use of a gammatone filter provides an impulse response as the product of a gamma function and a tone. The output of the gammatone filter can be regarded as a measurement of the basilar membrane displacement. Most CASA systems represent the firing rate in the auditory nerve rather than a spike-based. To obtain this, the filter bank outputs are half-wave rectified followed by a square root.

Endolymph is a fluid similar in composition to the intracellular fluid found inside cells. The organ of Corti is located in this duct on the basilar membrane, and transforms mechanical waves to electric signals in neurons. The other two sections are known as the scala tympani and the scala vestibuli. These are located within the bony labyrinth, which is filled with fluid called perilymph, similar in composition to cerebrospinal fluid.

At high sounds levels, nerve fibers whose characteristic frequencies do not exactly match the stimulus still respond, because of the motion induced in larger areas of the basilar membrane by loud sounds. Temporal theory can help explain how we maintain this discrimination. Even when a larger group of nerve fibers are all firing, there is a periodicity to this firing, which corresponds to the periodicity of the stimulus.

In an 1856 paper he described what were to become known as the "cells of Claudius", which are cells located on the basilar membrane of the inner ear's cochlea. His name is also associated with "Claudius' fossa", now referred to as the ovarian fossa, a depression in the parietal peritoneum of the pelvis. In 1867 he published Das Gehörorgan von Rhytina stelleri ("The hearing organ of Rhytina stelleri ").

Mayfield told the surgeon to contact the props man on the set of the TV show, Ben Casey, where their use had been featured in a recent episode. Modifications and improvements to the Mayfield clip followed. Charles Drake worked with Mayfield to develop a fenestrated clip through which the posterior cerebral artery could pass, thus facilitating occlusion of basilar terminus aneurysms. That clip would be called the Drake fenestrated clip.

The pontine nuclei is responsible for projecting axons that go to the opposite cerebellar hemisphere through the middle cerebellar peduncle. Doing this makes the axons change into the transverse pontine fibers. The fibers of the pontine nuclei are all important to motor function, including fiber bundles such as the corticospinal fibers and corticopontine-pontocerebellar system. Specifically, the basilar pons contains all the corticofugal fibers, which include the corticospinal, corticobulbar (or corticonuclear), and corticopontine fibers.

A single pulse caused the beetle to land again. Stimulation of basilar flight muscles allowed the controller to direct the insect left or right, although this was successful on only 75% of stimulations. After each maneuver, the beetles quickly righted themselves and continued flying parallel to the ground. In 2015, researchers was able to fine tune the beetle steering in flight by changing the pulse train applied on the wing-folding muscle.

The basilar part of the occipital bone (also basioccipital) extends forward and upward from the foramen magnum, and presents in front an area more or less quadrilateral in outline. In the young skull this area is rough and uneven, and is joined to the body of the sphenoid by a plate of cartilage. By the twenty-fifth year this cartilaginous plate is ossified, and the occipital and sphenoid form a continuous bone.

Figure 3 gives an impression of how loudness information is summed over a period of about 200 ms before being sent to the auditory cortex. Louder signals create a greater 'push' on the Basilar membrane and thus stimulate more nerves, creating a stronger loudness signal. A more complex signal also creates more nerve firings and so sounds louder (for the same wave amplitude) than a simpler sound, such as a sine wave.

Here, it wraps posteriorly around the pons (to which it also supplies blood) before reaching the cerebellum. The SCA supplies blood to most of the cerebellar cortex, the cerebellar nuclei, and the superior cerebellar peduncles. The AICA branches off the lateral portion of the basilar artery, just superior to the junction of the vertebral arteries. From its origin, it branches along the inferior portion of the pons at the cerebellopontine angle before reaching the cerebellum.

The vestibular membrane, vestibular wall or Reissner's membrane, is a membrane inside the cochlea of the inner ear. It separates the cochlear duct from the vestibular duct. Together with the basilar membrane it creates a compartment in the cochlea filled with endolymph, which is important for the function of the spiral organ of Corti. It primarily functions as a diffusion barrier, allowing nutrients to travel from the perilymph to the endolymph of the membranous labyrinth.

Vibrations from the oval window of the inner ear is transferred to the perilymph in the upper canal via a pressure wave. The Reissner's membrane transfers the vibrations to the endolymph of the middle canal. The Basilar membrane then vibrates and triggers the hair cells of the organ of Corti. The kinetic energy is converted to electrochemical energy as the auditory nerve transmits the information to the brain where sound is interpreted.

This causes depolarization of the hair cells and ultimately a conversion of the acoustic signal into a neuronal signal. While the hair cells do not produce action potentials themselves, they release neurotransmitter at synapses with the fibers of the auditory nerve, which does produce action potentials. In this way, the patterns of oscillations on the basilar membrane are converted to spatiotemporal patterns of firings which transmit information about the sound to the brainstem.

Both types of pillar cell have thousands of cross linked microtubules and actin filaments in parallel orientation. They provide mechanical coupling between the basement membrane and the mechanoreceptors on the hair cells. Boettcher's cells are found in the organ of Corti where they are present only in the lower turn of the cochlea. They lie on the basilar membrane beneath Claudius' cells and are organized in rows, the number of which varies between species.

Zolmitriptan is used for the acute treatment of migraines with or without aura in adults. Zolmitriptan is not intended for the prophylactic therapy of migraine or for use in the management of hemiplegic or basilar migraine. Zolmitriptan is available as a swallowable tablet, an oral disintegrating tablet, and a nasal spray, in doses of 2.5 and 5 mg. People who get migraines from aspartame should not use the disintegrating tablet (Zomig ZMT), which contains aspartame.

Earnhardt's death was officially pronounced at the Halifax Medical Center at 5:16 PM Eastern Standard Time (22:16 UTC); he was 49 years old. NASCAR president Mike Helton confirmed Earnhardt's death in a statement to the press. An autopsy conducted on February 19, 2001 concluded that Earnhardt sustained a fatal basilar skull fracture. Days later, on February 22, public funeral services were held at the Calvary Church in Charlotte, North Carolina.

Branches of the basilar and PCA supply the occipital lobe, brain stem, and the cerebellum. Ischemia is the loss of blood flow to the focal region of the brain. This produces heterogeneous areas of ischemia at the affected vascular region, furthermore, blood flow is limited to a residual flow. Regions with blood flow of less than 10 mL/100 g of tissue/min are core regions (cells here die within minutes of a stroke).

The fossil consists of a single partial left maxilla, an upper jaw bone, with seven teeth. The jaw measured 10.5 cm, with an estimated skull of 38.7 cm for the living animal. The teeth possess similarities with that of Scelidosaurus, which approaches it narrowly by the presence of important anterior and posterior basilar points on each tooth. The maxilla was clearly bigger, being the double of the size than the maxilla of Scelidosaurus.

Patients often survive on the collateral circulation from the back (posterior) of the circle of Willis, arising from the basilar artery. The arterial constrictions in moyamoya disease are unlike the constrictions in atherosclerosis. In atherosclerosis, the walls of arteries are damaged, leading to the deposition of fat and immune cells, and ultimately the accumulation of immune cells laden with fat. In moyamoya, the inner layer of the carotid artery proliferates within the arterial lumen.

Upon deflection of the basilar membrane upwards and subsequent deflection of the hair bundles toward the tallest steroecilia, channels within the stereocilia open allowing the inflow of ions and depolarizing the OHC results. Intracellular chloride dissociates from the allosteric binding sites in prestin, causing contraction of prestin. Upon BM deflection downwards hyperpolarization of the OHC results, and intracellular chloride ions bind allosterically causing prestin expansion. The binding or dissociation of chloride causes a shift in prestin's membrane capacitance.

Damage to the cochlea can occur in several ways, for example by viral infection, exposure to ototoxic chemicals, and intense noise exposure. Damage to the OHCs results in either a less effective active mechanism, or it may not function at all. OHCs contribute to providing a high sensitivity to quiet sounds at a specific range of frequencies (approximately 2–4 kHz). Thus, damage to the OHCs results in the reduction of sensitivity of the basilar membrane to weak sounds.

As in all lepidosaurs and archosaurs, the single-ossicle (columellar) middle ear transmits sound to the footplate of the columella, which sends a pressure wave through the inner ear. In snakes, the basilar papilla is roughly 1mm long and only responds to frequencies below about 1 kHz. In contrast, lizards tend to have two areas of hair cells, one responding below and the other above 1 kHz. The upper frequency limit in most lizards is roughly 5–8 kHz.

Tympanic cavity Hemotympanum or hematotympanum, refers to the presence of blood in the tympanic cavity of the middle ear. Hemotympanum is often the result of basilar skull fracture.. It may also be secondary to fractures of the mandibular condyles. Blueprints Neurology, 2nd ed Hemotympanum refers to the presence of blood in the middle ear, which is the area behind the eardrum. In most cases, the blood is trapped behind the eardrum, so no discharge is visible.

If caused by a head injury, rhinorrhea can be a much more serious condition. A basilar skull fracture can result in a rupture of the barrier between the sinonasal cavity and the anterior cranial fossae or the middle cranial fossae. This rupture can cause the nasal cavity to fill with cerebrospinal fluid. This condition, known as cerebrospinal fluid rhinorrhoea or CSF rhinorrhea, can lead to a number of serious complications and possibly death if not addressed properly.

With the eyes in the primary position, the sclera can be seen above the cornea, and further upgaze increases the distance between the eyelids and irises. Causes include upper dorsal midbrain supranuclear lesions such as Parinaud's syndrome, 'top of the basilar syndrome', midbrain infarction, neurodegeneration or tumour, multiple sclerosis, encephalitis, and Miller- Fisher syndrome. The cause is thought to be damage to the posterior commissure levator inhibitory fibres which originate in the M-group of neurons.

The PICA branches off the lateral portion of the vertebral arteries just inferior to their junction with the basilar artery. Before reaching the inferior surface of the cerebellum, the PICA sends branches into the medulla, supplying blood to several cranial nerve nuclei. In the cerebellum, the PICA supplies blood to the posterior inferior portion of the cerebellum, the inferior cerebellar peduncle, the nucleus ambiguus, the vagus motor nucleus, the spinal trigeminal nucleus, the solitary nucleus, and the vestibulocochlear nuclei.

Frequency detection by the alt= Research has developed a biological model as to how the meaning of speech can be perceived instantaneously even though the sentence has never been heard before. An understanding of syntactic, lexical and phonemic characteristics is first required for this to occur. Speech perception also requires the physical components of the auditory system to recognise similarities in sounds. Within the basilar membrane, energy is transferred, and specific frequencies can be detected and activate auditory hairs.

The pain is frequently accompanied by nausea, vomiting, sensitivity to light, sensitivity to sound, sensitivity to smells, fatigue and irritability. Many thus seek a dark and quiet room. In a basilar migraine, a migraine with neurological symptoms related to the brain stem or with neurological symptoms on both sides of the body, common effects include a sense of the world spinning, light-headedness, and confusion. Nausea occurs in almost 90% of people, and vomiting occurs in about one-third.

In these circumstances, insertion of the NPA can cause neurological damage by entering the cranium during placement. There is no consensus, however, regarding the risk of neurological damage secondary to a basilar skull fracture compared to hypoxia due to insufficient airway management. Other complications of Nasopharyngeal airways use includes laryngospasm, epistaxis, vomiting, and tissue necrosis with prolonged use.Oropharyngeal airways in a range of sizes Oropharyngeal airways are curved, rigid plastic devices, inserted into the patient's mouth.

Changes in the spatial responses in these subjects showed similar pitch judgment abilities when compared to subjects with normal spatial responses. This was especially true regarding low frequency stimuli. These results suggest that the place theory of hearing does not explain pitch perception at low frequencies, but that the temporal (frequency) theory is more likely. This conclusion is due to the finding that when deprived of basilar membrane place information, these patients still demonstrated normal pitch perception.

Foville's syndrome is caused by the blockage of the perforating branches of the basilar artery in the region of the brainstem known as the pons. Most frequently caused by vascular disease or tumors involving the dorsal pons. Structures affected by the infarct are the PPRF, nuclei of cranial nerves VI and VII, corticospinal tract, medial lemniscus, and the medial longitudinal fasciculus. There's involvement of the fifth to eighth cranial nerves, central sympathetic fibres (Horner syndrome) and horizontal gaze palsy.

Basilar invagination can be present at birth. If the condition develops after birth, it is usually the result of injury or diseases. If due to injury, about half the time it is caused by vehicle or bicycle accidents; 25% of the time by falls and 10% of the time by recreational activities such as diving accidents. It also occurs in patients with bone diseases, such as osteomalacia, rheumatoid arthritis, Paget's disease, Ehlers-Danlos syndrome, Marfan syndrome, and osteogenesis imperfecta.

Sexual intercourse can also trigger a subarachnoid hemorrhage via the Valsalva maneuver. A 2011 meta-analysis published in Journal of Sexual Medicine found that men who were unfaithful were significantly more likely than those who were faithful to experience severe or fatal cardiac events during sex. Basilar artery dissection has also been reported in connection with sexual activity, though most coital cephalalgia is benign in nature. Deaths during consensual sex only account for approximately 0.6% of all sudden deaths.

Examples are the waves at the surface of water and air (ocean surface waves). Another example is internal waves, which can be transmitted along the interface of two water masses of different densities. In theory of hearing physiology, the traveling wave (TW) of Von Bekesy, resulted from an acoustic surface wave of the basilar membrane into the cochlear duct. His theory purported to explain every feature of the auditory sensation owing to these passive mechanical phenomena.

However, at the apex the membrane is wide and flexible and is most responsive to low frequencies. Therefore, different sections of the basilar membrane vibrate depending on the frequency of the sound and give a maximum response at that particular frequency. In an impaired ear, however the auditory filter has a different shape compared to that of a 'normal' ear. The auditory filter of an impaired cochlea The auditory filter of an impaired ear is flatter and broader compared to a normal ear.

Paul Brophy (April 27, 1937 – October 23, 1986) was a firefighter in Massachusetts who entered a persistent vegetative state with no believed chance of recovery. Opposing viewpoints between his family and his doctors on how to deal with his condition sparked an early legal case on the right to die. On March 22, 1983, Paul Brophy sustained a basilar artery aneurysm rupture with very destructive neurologic consequences. Following the rupture he entered a persistent vegetative state with no chance of recovery.

Increased sensitivity in females to the "Qui" note and in males to the "Co" note explains the difference in behavioral responsiveness of each sex to the note of the call that is biologically relevant. The low and mid frequency units are thought to derive from the amphibian papilla, whereas the high frequency units correspond to the basilar papilla.Feng, A.S., Narins, P.M., and Capranica, R.R. 1975. Three populations of primary auditory fibers in the bullfrog (Rana catesbiana): their peripheral origins and frequency sensitivities.

Showing population atlases identifying regional differences in radial thickness at end-systolic cardiac phase between patients with hypertrophic cardiomyopathy (left) and hypertensive heart disease (right). Gray mesh shows the common surface template to the population, with the color map representing basilar septal and anterior epicardial wall with larger radial thickness in patients with hypertrophic cardiomyopathy vs. hypertensive heart disease. Numerous studies have now been done on cardiac hypertrophy and the role of the structural integraties in the functional mechanics of the heart.

The stereocilia atop the IHCs move with this fluid displacement and in response their cation, or positive ion selective, channels are pulled open by cadherin structures called tip links that connect adjacent stereocilia. The organ of Corti, surrounded in potassium-rich fluid endolymph, lies on the basilar membrane at the base of the scala media. Under the organ of Corti is the scala tympani and above it, the scala vestibuli. Both structures exist in a low potassium fluid called perilymph.

A HANS device (Head and Neck Support device) is a product which is part of a family of devices known as head restraints. Head restraints are safety items which are mandatory when competing with most major motorsports sanctioning bodies. These devices reduce the likelihood of head and/or neck injuries, including the often fatal basilar skull fracture, in the event of a crash. There are many such devices on the market today, but the HANS is the original and the most common.

Nerve fiber innervation is much denser for inner hair cells than for outer hair cells. A single inner hair cell is innervated by numerous nerve fibers, whereas a single nerve fiber innervates many outer hair cells. Inner hair cell nerve fibers are also very heavily myelinated, which is in contrast to the unmyelinated outer hair cell nerve fibers. The region of the basilar membrane supplying the inputs to a particular afferent nerve fibre can be considered to be its receptive field.

Ultimately, as new methods of studying the inner ear came about, a combination of place theory and frequency theory was adopted. Today, it is widely believed that hearing follows the rules of the frequency theory, including volley theory, at frequencies below 1000 Hz and place theory at frequencies above 5000 Hz. For sounds with frequencies between 1000 and 5000 Hz, both theories come into play so the brain can utilize the basilar membrane location and the rate of the impulse.

Frequencies this low still activate the organ of Corti to some extent but are too low to elicit the perception of a pitch. Higher frequencies do not propagate to the helicotrema, due to the stiffness- mediated tonotopy. A very strong movement of the basilar membrane due to very loud noise may cause hair cells to die. This is a common cause of partial hearing loss and is the reason why users of firearms or heavy machinery often wear earmuffs or earplugs.

The direct cause of death was a basilar skull fracture caused by rapid head movement to the right. Williams, in the live interview where McDuffie's death was confirmed, erroneously reported that McDuffie was 53; he would not have been 53 until December 5 of that year. NASCAR also erroneously reported that McDuffie was 53. McDuffie's death led to changes at Watkins Glen and also influenced motorsport safety changes that would come to full fruition at the end of the decade.

In central herniation, the diencephalon and parts of the temporal lobes of both of the cerebral hemispheres are squeezed through a notch in the tentorium cerebelli. Transtentorial herniation can occur when the brain moves either up or down across the tentorium, called ascending and descending transtentorial herniation respectively; however descending herniation is much more common. Downward herniation can stretch branches of the basilar artery (pontine arteries), causing them to tear and bleed, known as a Duret hemorrhage. The result is usually fatal.

Hajdu–Cheney syndrome causes many issues with an individual’s connective tissues. Some general characteristics of an individual with Hajdu–Cheney syndrome include bone flexibility and deformities, short stature, delayed acquisition of speech and motor skills, dolichocephalic skull, Wormian bone, small maxilla, hypoplastic frontal sinuses, basilar impression, joint laxity, bulbous finger tips and severe osteoporosis. Wormian bone occurs when extra bones appear between cranial sutures. Fetuses with Hajdu–Cheney syndrome often will not be seen to unclench their hands on obstetrical ultrasound.

Activity of the same muscle in flight affects the power output of the wing and so it is also important in flight control. In orthopteroid insects, the elasticity of the cuticle causes the vannal area of the wing to fold along the veins. Consequently, energy is expended in unfolding this region when the wings are moved to the flight position. In general, wing extension probably results from the contraction of muscles attached to the basilar sclerite or, in some insects, to the subalar sclerite.

This selectivity to certain frequencies can be illustrated by neural tuning curves. These demonstrate the frequencies a fiber responds to, by showing threshold levels (dB SPL) of auditory nerve fibers as a function of different frequencies. This demonstrates that auditory nerve fibers respond best, and hence have better thresholds at the fiber's characteristic frequency and frequencies immediately surrounding it. The basilar membrane is said to be ‘sharply tuned’ due to the sharp ‘V’ shaped curve, with its ‘tip’ centered at the auditory fibers characteristic frequency.

The development of the most basic basilar papilla (the auditory organ that later evolved into the Organ of Corti in mammals) happened at the same time as the water-to-land transition of vertebrates, approximately 380 million years ago. The actual coiling or spiral nature of the cochlea occurred to save space inside the skull. The longer the cochlea, the higher is the potential resolution of sound frequencies given the same hearing range. The oldest of the truly coiled mammalian cochleae were approximately 4 mm in length.

Anterior premaxilla broad and blunt, in dorsal view the premaxillary-maxillary suture is oblique. The ectopterygoid is lightly built and composed of a distinct small subrectangular pterygoid process and a slender rod-like jugal process. Incipient emargination of the frontal by the external nares. A pair of foramina separated by a thin median septum in the floor of the basioccipital are interpreted as the entrance of the basilar artery, and exit the ventral surface of the basioccipital as multiple small and anteriorly placed foramina.

Stanley Smith (born September 29, 1949) is a retired NASCAR driver and dirt- track racer. At the 1993 DieHard 500 at Talladega, Smith nearly died from a basilar skull fracture in a massive crash—the same type of injury that later killed Tony Roper, Adam Petty, Kenny Irwin Jr., Dale Earnhardt and Jason Leffler. Fortunately, Smith was able to recover from the injury. The crash was better known for fellow competitor Jimmy Horton flipping over the wall and rolling down the embankment outside the track.

The loose fibrous mass of the tympanic part arises at the proximal tip along with the dense fibrous mass, but the loose fibrous mass covers a greater width of the basilar membrane. The only thing that separates the vestibular and tympanic parts are thin, discontinuous cords of fibers. These cords of fibers are visible at the pendulous tympanic edge of the loose fibrous mass in the proximal part of the papilla, but are much more scattered throughout the mass distally.Smith, C., Konishi, M., & Schuff, N. 1985.

Activity of the same muscle in flight affects the power output of the wing and so it is also important in flight control. In orthopteroid insects, the elasticity of the cuticle causes the vannal area of the wing to fold along the veins. Consequently, energy is expended in unfolding this region when the wings are moved to the flight position. In general, wing extension probably results from the contraction of muscles attached to the basilar sclerite or, in some insects, to the subalar sclerite.

The pre-hospital setting provides unique challenges to management of the airway including tight spaces, neck immobilization, poor lighting, and often the added complexity of attempting procedures during transport. When possible, basic airway management should be prioritized including head-tilt-chin-lift maneuvers, and bag-valve masking. If ineffective, a supraglottic airway can be utilized to aid in oxygenation and maintenance of a patent airway. An oropharyngeal airway is acceptable, however nasopharyngeal airways should be avoided in trauma, particularly if a basilar skull fracture is suspected.

With the movement of the basilar membrane, a shear force is created and a small potential is generated due to a difference in potential between the endolymph (scala media- +80 mV) and the perilymph (vestibular and tympanic ducts- -70 mV). EP is highest in the basal turn of the Cochlea and decreases in the magnitude towards the apex. EP is highly dependent on the metabolism and ionic transport. An acoustic stimulus produces a simultaneous change in conductance at the membrane of the receptor cell.

After exiting at the level of the first cervical vertebra, its course changes from vertical to horizontal, and then enters the skull through the foramen magnum. Inside the skull, the arteries merge to form the basilar artery, which joins the circle of Willis. In total, three quarters of the artery are outside the skull; it has a high mobility in this area due to rotational movement in the neck and is therefore vulnerable to trauma. Most dissections happen at the level of the first and second vertebrae.

Electromotility of the OHC by prestin modulation produces significantly larger forces than the forces generated by deflection of the hair bundle. One experiment showed that the somatic motor produced a 40-fold greater force at the apical membrane and a sixfold greater force at the basilar membrane than the hair bundle motor. The difference in these two motors is that there are different polarities of hair bundle deflection for each motor. The hair bundle motor uses a positive deflection leading to a generation of force, while the somatic motor uses negative deflection to generate force.

He seems to have recognised the communication of the convoluted surface of the brain and that between the lateral cavities beneath the fornix. He described the corpora striata and optic thalami; the four orbicular eminences, with the bridge, which he first named annular protuberance; and the white mammillary eminences, behind the infundibulum. In the cerebellum he remarks the arborescent arrangement of the white and grey matter and gives a good account of the internal carotids and the communications which they make with the branches of the basilar artery. Willis replaced Nemesius's doctrine.

Acoustic resonance is also important for hearing. For example, resonance of a stiff structural element, called the basilar membrane within the cochlea of the inner ear allows hair cells on the membrane to detect sound. (For mammals the membrane has tapering resonances across its length so that high frequencies are concentrated on one end and low frequencies on the other.) Like mechanical resonance, acoustic resonance can result in catastrophic failure of the vibrator. The classic example of this is breaking a wine glass with sound at the precise resonant frequency of the glass.

Neural structures form and become more sophisticated as a result of experience. For example, the preference for consonance, the harmony or agreement of components, over dissonance, an unstable tone combination, is found early in development. Research suggests that this is due to both the experiencing of structured sounds and the fact they stem from development of the basilar membrane and auditory nerve, two early developing structures in the brain. An incoming auditory stimulus evokes responses measured in the form of an event- related potential (ERP), measured brain responses resulting directly from a thought or perception.

Two nostrils, along with four other external openings, appear between the premaxilla and lateral rostral bones. The nasal sacs resemble those of many other fish and do not contain an internal nostril. The coelacanth's rostral organ, contained within the ethmoid region of the braincase, has three unguarded openings into the environment and is used as a part of the coelacanth's laterosensory system. The coelacanth's auditory reception is mediated by its inner ear, which is very similar to that of tetrapods because it is classified as being a basilar papilla.

Dead regions affect audiometric results, but perhaps not in the way expected. For example, it may be expected that thresholds would not be obtained at the frequencies within the dead region, but would be obtained at frequencies adjacent to the dead region. Therefore, assuming normal hearing exists around the dead region, it would produce an audiogram that has a dramatically steep slope between the frequency where a threshold is obtained, and the frequency where a threshold cannot be obtained due to the dead region. Figure 7: Response of the basilar membrane to a pure tone.

Siamak Ardekani has been working on populations of Cardiac anatomies reconstructing atlas coordinate systems from populations. The figure on the right shows the computational cardiac anatomy method being used to identify regional differences in radial thickness at end-systolic cardiac phase between patients with hypertrophic cardiomyopathy (left) and hypertensive heart disease (right). Color map that is placed on a common surface template (gray mesh) represents region ( basilar septal and the anterior epicardial wall) that has on average significantly larger radial thickness in patients with hypertrophic cardiomyopathy vs. hypertensive heart disease (reference below).

The first feather resulted when undifferentiated tubular follicle collar developed out of the old keratinocytes being pushed out. At stage II, the inner, basilar layer of the follicle collar differentiated into longitudinal barb ridges with unbranched keratin filaments, while the thin peripheral layer of the collar became the deciduous sheath, forming a tuft of unbranched barbs with a basal calamus. Stage III consists of two developmental novelties, IIIa and IIIb, as either could have occurred first. Stage IIIa involves helical displacement of barb ridges arising within the collar.

The clivus (Latin for "slope") is a bony part of the cranium at the skull base, a shallow depression behind the dorsum sellæ that slopes obliquely backward. It forms a gradual sloping process at the anterior most portion of the basilar occipital bone at its junction with the sphenoid bone. On axial planes, it sits just posterior to the sphenoid sinuses. Just lateral to the clivus bilaterally is the foramen lacerum (the internal carotid artery reaches the middle cranial fossa above the foramen lacerum), proximal to its anastomosis with the Circle of Willis.

In 1990 in Anderson, Indiana, physician Frank Meshberger noted in the Journal of the American Medical Association that the background figures and shapes portrayed behind the figure of God appeared to be an anatomically accurate picture of the human brain. Pdf. Excerpt on Mental Health & Illness.com. Retrieved 21 September 2010. On close examination, borders in the painting correlate with major sulci of the cerebrum in the inner and outer surface of the brain, the brain stem, the frontal lobe, the basilar artery, the pituitary gland and the optic chiasm.

In cases involving the basilar artery (VBD), pathology can occur due to direct compression of cranial nerves, by ischemia related to the dolichoectatic vessel, or by the development of hydrocephalus. Rupture of the dolichoectatic vessel can lead to catastrophic intracerebral hemorrhage. Internal carotid artery dolichoectasia is particularly interesting because the artery normally already contains one hairpin turn. Seen in an MRI as two individual arteries at this hairpin, a carotid artery dolichoectasia can progress so far as to produce a second hairpin turn and appear as three individual arteries on an MRI.

The RM separates endolymph in the cochlear duct from underlying corticolymph and perilymph of the scala tympani. The hair processes of the outer hair cells emerge through and above the RM, thus immobilizing the apical pole of the outer hair cells. At the opposite basilar pole, the outer hair cells are firmly held by the phalangeal cells. The inner phalangeal cells that surround the inner hair cells reach the surface of the organ of corti, but, even their inner-most row, are not included in the reticular membrane.

400x400px Hair cells are the sensory receptors of both the auditory system and the vestibular system in the ears of all vertebrates, and in the lateral line organ of fishes. Through mechanotransduction, hair cells detect movement in their environment. In mammals, the auditory hair cells are located within the spiral organ of Corti on the thin basilar membrane in the cochlea of the inner ear. They derive their name from the tufts of stereocilia called hair bundles that protrude from the apical surface of the cell into the fluid-filled cochlear duct.

"Implementation details of a computational model of the inner hair-cell/auditory nerve synapse". Journal of the Acoustical Society of America 87(4) 1813-1816. Based on the assumption that there are three reservoirs of transmitter substance within each hair cell, and the transmitters are released in proportion to the degree of displacement to the basilar membrane, the release is equated with the probability of a spike generated in the nerve fiber. This model replicates many of the nerve responses in the CASA systems such as rectification, compression, spontaneous firing, and adaptation.

The utricular division of the auditory vesicle also responds to angular acceleration, as well as the endolymphatic sac and duct that connect the saccule and utricle. Beginning in the fifth week of development, the auditory vesicle also gives rise to the cochlear duct, which contains the spiral organ of Corti and the endolymph that accumulates in the membranous labyrinth. The vestibular wall will separate the cochlear duct from the perilymphatic scala vestibuli, a cavity inside the cochlea. The basilar membrane separates the cochlear duct from the scala tympani, a cavity within the cochlear labyrinth.

Neurons within the ear respond to simple tones, and the brain serves to process other increasingly complex sounds. An average adult is typically able to detect sounds ranging between 20 and 20,000 Hz. The ability to detect higher pitch sounds decreases in older humans. The human ear has evolved with two basic tools to encode sound waves; each is separate in detecting high and low-frequency sounds. Georg von Békésy (1899-1972) employed the use of a microscope in order to examine the basilar membrane located within the inner-ear of cadavers.

In the cochlea, a shearing movement between the tectorial membrane and the basilar membrane deflects the stereocilia, affecting the tension on the tip-link filaments, which then open and close the non-specific ion channels. When tension increases, the flow of ions across the membrane into the hair cell rises as well. Such influx of ions causes a depolarization of the cell, resulting in an electrical potential that ultimately leads to a signal for the auditory nerve and the brain. The identity of the mechanosensitive channels in the stereocilia is still unknown.

Békésy later developed a mechanical model of the cochlea, which confirmed the concept of frequency dispersion by the basilar membrane in the mammalian cochlea. In an article published posthumously in 1974, Békésy reviewed progress in the field, remarking "In time, I came to the conclusion that the dehydrated cats and the application of Fourier analysis to hearing problems became more and more a handicap for research in hearing," referring to the difficulties in getting animal preparations to behave as when alive, and the misleading common interpretations of Fourier analysis in hearing research.

Georg Ohm applied Fourier's theory to sound in 1843. The line of work was greatly advanced by Hermann von Helmholtz, who published his eight years worth of research in 1863. Helmholtz believed that the psychological perception of tone color is subject to learning, while hearing in the sensory sense is purely physiological. He supported the idea that perception of sound derives from signals from nerve cells of the basilar membrane and that the elastic appendages of these cells are sympathetically vibrated by pure sinusoidal tones of appropriate frequencies.

The dorsum sellae is part of the sphenoid bone in the skull. Together with the basilar part of the occipital bone it forms the clivus. In the sphenoid bone, the anterior boundary of the sella turcica is completed by two small eminences, one on either side, called the middle clinoid processes, while the posterior boundary is formed by a square-shaped plate of bone, the dorsum sellae, ending at its superior angles in two tubercles, the posterior clinoid processes, the size and form of which vary considerably in different individuals.

The temporal theory of hearing states that human perception of sound depends on temporal patterns with which neurons respond to sound in the cochlea. Therefore, in this theory, the pitch of a pure tone is determined by the period of neuron firing patterns—either of single neurons, or groups as described by the volley theory. Temporal or timing theory competes with the place theory of hearing, which instead states that pitch is signaled according to the locations of vibrations along the basilar membrane. Temporal theory was first suggested by August Seebeck.

From 1990–1992, New Hampshire held a second Busch Series race in the fall. The second race was removed from the schedule in 1993, in exchange for a Winston Cup Series race at the track. During the practice for the 2000 event, Adam Petty died after he lost control of his car after his throttle were stuck wide open going into turn three; Petty's death was caused by a basilar skull fracture from the ensuing impact. Cup Series driver Kenny Irwin Jr. also died under similar circumstances during the practice of thatlook.

Benign paroxysmal vertigo of childhood is an example of migraine-associated vertigo in which headache does not often occur. Basilar artery migraine (BAM) consists of two or more symptoms (vertigo, tinnitus, decreased hearing, ataxia, dysarthria, visual symptoms in both hemifields or both eyes, diplopia, bilateral paresthesias, paresis, decreased consciousness and/or loss of consciousness) followed by throbbing headache. Auditory symptoms are rare. However, a study showed a fluctuating low-tone sensorineural hearing loss in more than 50% of patients with BAM with a noticeable change in hearing just before the onset of a migraine headache.

Like the males, females can distinguish the minute differences between individual frogs. However, males and females are attuned to different parts of the advertisement call. For example, males of the onomatopoeically named coqui species are more attuned to the low frequency co part of the call, whereas females are more attuned to the high frequency qui.Narins and Capranica (1980) In fact, the order of the parts does not matter. Similarly, for females of the Tungara species, the female basilar papilla is biased towards a lower-than-average “chuck” portion of a male call.

The left and right internal carotid arteries arise from the left and right common carotid arteries. The posterior communicating artery is given off as a branch of the internal carotid artery just before it divides into its terminal branches - the anterior and middle cerebral arteries. The anterior cerebral artery forms the anterolateral portion of the circle of Willis, while the middle cerebral artery does not contribute to the circle. The right and left posterior cerebral arteries arise from the basilar artery, which is formed by the left and right vertebral arteries.

The tonotopic layout of sound information begins in the cochlea where the basilar membrane vibrates at different positions along its length depending upon the frequency of the sound. Higher frequency sounds are at the base of the cochlea, if it were unrolled, and low frequency sounds are at the apex. This arrangement is also found in the auditory cortex in the temporal lobe. In areas that are tonotopically organized, the frequency varies systematically from low to high along the surface of the cortex, but is relatively constant across cortical depth.

A reconstruction of the vertebral arteries from a CT scan, seen from the front. From the bottom, V1 is from the subclavian artery to the foramina, V2 is from the foramina to the second vertebra, V3 is between the foramina until entry into the skull, and V4 is inside the skull embedded in the dura mater. They merge into the basilar artery, which then divides into the posterior cerebral artery. The vertebral arteries arise from the subclavian artery, and run through the transverse foramen of the upper six vertebrae of the neck.

Similarities between sensory processes of the skin and the auditory system suggest lateral inhibition could play a role in auditory processing. The basilar membrane in the cochlea has receptive fields similar to the receptive fields of the skin and eyes. Also, neighboring cells in the auditory cortex have similar specific frequencies that cause them to fire, creating a map of sound frequencies similar to that of the somatosensory cortex. Lateral inhibition in tonotopic channels can be found in the inferior colliculus and at higher levels of auditory processing in the brain.

In some species such as the bullfrog, the size of the tympanum indicates the sex of the frog; males have tympani that are larger than their eyes while in females, the eyes and tympani are much the same size. A noise causes the tympanum to vibrate and the sound is transmitted to the middle and inner ear. The middle ear contains semicircular canals which help control balance and orientation. In the inner ear, the auditory hair cells are arranged in two areas of the cochlea, the basilar papilla and the amphibian papilla.

The basilar membrane within the cochlea contains the first of these specializations for echo information processing. In bats that use CF signals, the section of the membrane that responds to the frequency of returning echoes is much larger than the region of response for any other frequency. For example, in the greater horseshoe bat, Rhinolophus ferrumequinum, there is a disproportionately lengthened and thickened section of the membrane that responds to sounds around 83 kHz, the constant frequency of the echo produced by the bat's call. This area of high sensitivity to a specific, narrow range of frequency is known as an "acoustic fovea".

As a NASCAR driver, Pollard competed in the Busch Grand National Series from 1985 to 1990 while appearing in four races during the 1987 NASCAR Winston Cup Series season. While in the Busch Series, he won the 1987 Busch 200 at Langley Speedway and became the first non-American driver to win a Busch Series event. At the 1988 Budweiser 200 at Dover International Speedway, Pollard crashed into a wall during the 195th lap and acquired a basilar skull fracture. After coming out of a coma, Pollard returned to racing during the 1989 NASCAR Busch Series.

However, due to IHC damage, the whole tuning curve becomes raised, giving a loss of sensitivity across all frequencies (See Figure 6). It is only necessary for the first row of OHCs to be damaged for the elimination of the finely tuned ‘tip’ to occur. This supports the idea that the incidence of OHC damage and thus a loss of sensitivity to quiet sounds, occurs more than IHC loss. When the IHCs or part of the basilar membrane are damaged or destroyed, so that they no longer function as transducers, the result is a ‘dead region’.

One such mechanism is the opening of ion channels in the hair cells of the cochlea in the inner ear. Air pressure changes in the ear canal cause the vibrations of the tympanic membrane and middle ear ossicles. At the end of the ossicular chain, movement of the stapes footplate within the oval window of the cochlea, in turn, generates a pressure field within the cochlear fluids, imparting a pressure differential across the basilar membrane. A sinusoidal pressure wave results in localized vibrations of the organ of Corti: near the base for high frequencies, near the apex for low frequencies.

On June 17, 1987, a 19-year-old woman from Chester, Pennsylvania fell to her death as a result of not being properly secured by the over-the-shoulder harness. She was pronounced dead at a nearby hospital with Basilar skull fracture suffered from the fall. Early reports indicated that the woman tried to board late after the safety harness was locked and the attendant couldn't stop the train. An investigation found the ride itself to be operating properly, but that an error was made by the ride operator, who started the ride without ensuring all passengers were secured.

Frequency resolution occurs on the basilar membrane due to the listener choosing a filter which is centered over the frequency they expect to hear, the signal frequency. A sharply tuned filter has good frequency resolution as it allows the center frequencies through but not other frequencies (Pickles 1982). Damage to the cochlea and the outer hair cells in the cochlea can impair the ability to tell sounds apart (Moore 1986). This explains why someone with a hearing loss due to cochlea damage would have more difficulty than a normal hearing person in distinguishing between different consonants in speech.

Electrical measurements and predictions validate the cylinder cross-section model. In the CA3, the temporoammonic (TA), commissural (COM), associational (ASSOC), and mossy fiber (MF) afferents all make excitatory glutamatergic (Glu) synapses on pyramidal cell dendrites (both apical and basal). Since fast signals occurring in the basilar and proximal apical dendrites are transferred to the soma with at least a 20–25% efficiency, synapses in these dendrites each contribute more to the neuronal activation than distal apical synapses. In contrast, only slow signals from the distal dendrites are efficiently transferred to the soma, suggesting a modulatory role on the resting potential of the cell.

The tectorial membrane (TM) is one of two acellular membranes in the cochlea of the inner ear, the other being the basilar membrane (BM). "Tectorial" in anatomy means forming a cover. The TM is located above the spiral limbus and the spiral organ of Corti and extends along the longitudinal length of the cochlea parallel to the BM. Radially the TM is divided into three zones, the limbal, middle and marginal zones. Of these the limbal zone is the thinnest (transversally) and overlies the auditory teeth of Huschke with its inside edge attached to the spiral limbus.

400x400px The cochlea is filled with a watery liquid, the endolymph, which moves in response to the vibrations coming from the middle ear via the oval window. As the fluid moves, the cochlear partition (basilar membrane and organ of Corti) moves; thousands of hair cells sense the motion via their stereocilia, and convert that motion to electrical signals that are communicated via neurotransmitters to many thousands of nerve cells. These primary auditory neurons transform the signals into electrochemical impulses known as action potentials, which travel along the auditory nerve to structures in the brainstem for further processing.

It winds backward around the upper part of the medulla oblongata, passing between the origins of the vagus nerve and the accessory nerve, over the inferior cerebellar peduncle to the undersurface of the cerebellum, where it divides into two branches. The medial branch continues backward to the notch between the two hemispheres of the cerebellum; while the lateral supplies the under surface of the cerebellum, as far as its lateral border, where it anastomoses with the anterior inferior cerebellar and the superior cerebellar branches of the basilar artery. Branches from this artery supply the choroid plexus of the fourth ventricle.

Enterochromaffin-like cells, located within the gastric glands of the stomach, release histamine that stimulates nearby parietal cells by binding to the apical H2 receptor. Stimulation of the parietal cell induces the uptake of carbon dioxide and water from the blood, which is then converted to carbonic acid by the enzyme carbonic anhydrase. Inside the cytoplasm of the parietal cell, the carbonic acid readily dissociates into hydrogen and bicarbonate ions. The bicarbonate ions diffuse back through the basilar membrane and into the bloodstream, while the hydrogen ions are pumped into the lumen of the stomach via a K+/H+ ATPase pump.

Normally, blood flows from the aorta into the subclavian artery, and then some of that blood leaves via the vertebral artery to supply the brain. In SSS a reduced quantity of blood flows through the proximal subclavian artery. As a result, blood travels up one of the other blood vessels to the brain (the other vertebral or the carotids), reaches the basilar artery or goes around the cerebral arterial circle and descends via the (contralateral) vertebral artery to the subclavian (with the proximal blockage) and feeds blood to the distal subclavian artery (which supplies the upper limb and shoulder).

Theories of pitch perception try to explain how the physical sound and specific physiology of the auditory system work together to yield the experience of pitch. In general, pitch perception theories can be divided into place coding and temporal coding. Place theory holds that the perception of pitch is determined by the place of maximum excitation on the basilar membrane. A place code, taking advantage of the tonotopy in the auditory system, must be in effect for the perception of high frequencies, since neurons have an upper limit on how fast they can phase-lock their action potentials.

Each part of the basilar membrane, together with the surrounding fluid, can therefore be thought of as a "mass-spring" system with different resonant properties: high stiffness and low mass, hence high resonant frequencies at the near (base) end, and low stiffness and high mass, hence low resonant frequencies, at the far (apex) end. This causes sound input of a certain frequency to vibrate some locations of the membrane more than other locations. The distribution of frequencies to places is called the tonotopic organization of cochlea. Sound- driven vibrations travel as waves along this membrane, along which, in humans, lie about 3,500 inner hair cells spaced in a single row.

Outputs of simulated cochlear filters centred at 364, 1498 and 4803 Hz (from bottom to top) in response to a segment of a speech signal, the sound “en” in “sense”. These filter outputs are similar to the waveforms that would be observed at places on the basilar membrane tuned to 364, 1498 and 4803 Hz. For each centre frequency, the signal can be considered as a slowly-varying envelope (EBM) imposed on a more rapid temporal fine structure (TFSBM). The envelope for each band signal is shown by the thick line.Notions of temporal envelope and temporal fine structure may have different meanings in many studies.

Following his travels, Dănăilă was able to perform the most complex of neurosurgical operations, including occlusion of aneurysm of the arterial vertebro-basilar system, ablation of the third ventricle tumors, surgical management of skull base tumors, carotidian and middle cerebral endarterectomy, and extra- and intracranial anastomosis. He also succeeded in reducing operation mortality from operations to percentages comparable with those reported by the world's most reputable neurosurgical clinics. Thus the surgical mortality rate in Bucharest fell from 50% to 2-6% for acoustic nerve neuroma and from 49% to 3% for intracerebral aneurysm cases. These reductions were aided by the endowment of the operating theatre with a surgical microscope and laser.

Conductive hearing ability is mediated by the middle ear composed of the ossicles: the malleus, the incus, and the stapes. Sensorineural hearing ability is mediated by the inner ear composed of the cochlea with its internal basilar membrane and attached cochlear nerve (cranial nerve VIII). The outer ear consisting of the pinna, ear canal, and ear drum or tympanic membrane transmits sounds to the middle ear but does not contribute to the conduction or sensorineural hearing ability save for hearing transmissions limited by cerumen impaction (wax collection in the ear canal). The Weber test has had its value as a screening test questioned in the literature.

Several case reports can be found in the medical literature which connect excessive headbanging to aneurysms and hematomas within the brain and damage to the arteries in the neck which supply the brain. More specifically, cases with damage to the basilar artery, the carotid artery and the vertebral artery have been reported. Several case reports also associated headbanging with subdural hematoma, sometimes fatal, and mediastinal emphysema similar to shaken baby syndrome. An observational study comparing headbanging to non-headbanging teenagers in a dance marathon concluded that the activity is associated with pain in varying parts of the body, most notably the neck, where it manifests as whiplash.

Cross-section through the spiral organ of Corti at greater magnification, showing position of the hair cells on the basement membrane. The organ of Corti is located in the scala media of the cochlea of the inner ear between the vestibular duct and the tympanic duct and is composed of mechanosensory cells, known as hair cells. Strategically positioned on the basilar membrane of the organ of Corti are three rows of outer hair cells (OHCs) and one row of inner hair cells (IHCs). Separating these hair cells are supporting cells: Deiters cells, also called phalangeal cells, which separate and support both the OHCs and the IHCs.

On February 18, 2001, NASCAR driver and long-time friend of Hinton, Dale Earnhardt, was killed on the final turn of the Daytona 500. Hinton and the Sentinel suspected that, like Kenny Irwin and Adam Petty, Earnhardt's cause of death had been basilar skull fracture (Hinton had recently published a three-part series on the subject of NASCAR safety) and claimed that under Florida law, the state was legally required to turn over Earnhardt's autopsy photographs. Teresa Earnhardt and others claimed the newspaper could not have access to the photographs, leading to a First Amendment legal battle which was finally concluded by an official NASCAR report on Earnhardt's death.

They vary considerably in form and size, are seldom symmetrical, and are often partially subdivided by irregular bony laminae. Occasionally, they extend into the basilar part of the occipital bone nearly as far as the foramen magnum. They begin to be developed before birth, and are of a considerable size by the age of six. They are partially closed, in front and below, by two thin, curved plates of bone, the sphenoidal conchae, leaving in the articulated skull a round opening at the upper part of each sinus by which it communicates with the upper and back part of the nasal cavity and occasionally with the posterior ethmoidal air cells.

In the auditory system of bats, like in auditory systems of other vertebrates, primary sensory afferent neurons, which receive inputs from hair cells from a restricted region of the organ of Corti in the cochlea, are the simple feature detectors. These structures are sensitive to a restricted range of frequencies and therefore function as tuned filters. Experimentally, Nobuo Suga and his colleagues (1990) noted that various constant frequency (CF) and frequency modulated (FM) harmonics excited different parts of the basilar membrane because of the frequency difference in the call. Auditory nerve fibers take this slightly-processed sensory information to the cochlear nucleus where information either converges or diverges into parallel pathways.

Place theory is a theory of hearing that states that our perception of sound depends on where each component frequency produces vibrations along the basilar membrane. By this theory, the pitch of a sound, such as a human voice or a musical tone, is determined by the places where the membrane vibrates, based on frequencies corresponding to the tonotopic organization of the primary auditory neurons. More generally, schemes that base attributes of auditory perception on the neural firing rate as a function of place are known as rate–place schemes. The main alternative to the place theory is the temporal theory, also known as timing theory.

Then in 1998, Caitlín R. Kiernan extracted chalky matrix from the basilar canal of the basiocciptal and identified calcareous nanoplankton that indicated GSATC 221 had originated from basal Campanian beds within the lower unnamed member of the Mooreville Chalk Formation (Selma Group). In her study of Alabama mosasaur biostratigraphy, Kiernan placed S. russelli within the Clidastes Acme Zone, though it was the rarest element in the fauna, accounting for only 0.3% of the biozone's assemblage (one specimen).Kiernan, Caitlin R. 2002. Stratigraphic distribution and habitat segregation of mosasaurs in the Upper Cretaceous of western and central Alabama, with an historical review of Alabama mosasaur discoveries.

The most prominent figure in the creation of the place theory of hearing is Hermann von Helmholtz, who published his finished theory in 1885. Helmholtz claimed that the cochlea contained individual fibers for analyzing each pitch and delivering that information to the brain. Many followers revised and added to Helmholtz's theory and the consensus soon became that high frequency sounds were encoded near the base of the cochlea and that middle frequency sounds were encoded near the apex. Georg von Békésy developed a novel method of dissecting the inner ear and using stroboscopic illumination to observe the basilar membrane move, adding evidence to support the theory.

Vestibular duct perilymph vibrations bend organ of Corti outer cells (4 lines) causing prestin to be released in cell tips. This causes the cells to be chemically elongated and shrunk (somatic motor), and hair bundles to shift which, in turn, electrically affects the basilar membrane’s movement (hair-bundle motor). These motors (outer hair cells) amplify the traveling wave amplitudes over 40-fold. The outer hair cells (OHC) are minimally innervated by spiral ganglion in slow (unmyelinated) reciprocal communicative bundles (30+ hairs per nerve fiber); this contrasts inner hair cells (IHC) that have only afferent innervation (30+ nerve fibers per one hair) but are heavily connected.

The four parts of this muscle arise from: \- the lower third of the posterior margin of the medial pterygoid plate and its hamulus (Pterygopharyngeal part) \- from the pterygomandibular raphe (Buccopharyngeal part) \- from the alveolar process of the mandible above the posterior end of the mylohyoid line (Mylopharyngeal part) \- and by a few fibers from the side of the tongue (Glossopharyngeal part) The fibers curve backward to be inserted into the median raphe, being also prolonged by means of an aponeurosis to the pharyngeal spine on the basilar part of the occipital bone. The superior fibers arch beneath the levator veli palatini muscle and the Eustachian tube.

In 1905, she obtained her specialist certification in anatomy with the dissertation Recherches sur la morphologie de l'artère basilaire (Research on the morphology of the basilar artery). At this time, the university was undergoing to change in curriculum to focus more on research and De Vriese applied for an extension to her assistant's position to gain the necessary requirements for a lead researcher. Although praised by her colleagues, the rector, and the minister, the ministry refused to grant the extension. After a protracted period of petitioning, De Vriese left Ghent University in 1908 and Leboucq approved the candidacy of his son for the position.

The vestibulocochlear nerve is accompanied by the labyrinthine artery, which usually branches off from the anterior inferior cerebellar artery (AICA) at the cerebellopontine angle, and then goes with the 7th nerve through the internal acoustic meatus to the internal ear. The cochlear nerve travels away from the cochlea of the inner ear where it starts as the spiral ganglia. Processes from the organ of Corti conduct afferent transmission to the spiral ganglia. It is the inner hair cells of the organ of Corti that are responsible for activation of afferent receptors in response to pressure waves reaching the basilar membrane through the transduction of sound.

The old pitlane, June 2006. In the 1994 San Marino Grand Prix, during Friday practice Rubens Barrichello was launched over a kerb and into the top of a tyre barrier at the Variante Bassa, knocking the Brazilian unconscious, though quick medical intervention saved his life. During Saturday qualifying Austrian Roland Ratzenberger crashed head-on into a wall at over 310 km/h at the Villeneuve corner after his Simtek lost the front wing, dying instantly from a basilar skull fracture. The tragedy continued the next day, when the three-time World Champion Ayrton Senna lost control of his car and crashed into the concrete wall at the Tamburello corner on Lap 7.

At all but low frequencies, the neural measure averages over multiple cycles to give the equivalent of rectification followed by averaging (low-pass filtering). Over the entire cochlea, response shows as a pattern that varies more slowly that the applied frequency but that does follow the envelope of the applied signal. Each group of cells can give rise to a semi-periodic wave that can be analyzed by neurons in the brain. The total pattern that arises from a sound can thus be thought of as a two- dimensional pattern in time with one axis being the distance along the basilar membrane and the other being distance along some sequence of neurons.

The condyles are oval or reniform (kidney-shaped) in shape, and their anterior extremities, directed forward and medialward, are closer together than their posterior, and encroach on the basilar portion of the bone; the posterior extremities extend back to the level of the middle of the foramen magnum. The articular surfaces of the condyles are convex from before backward and from side to side, and look downward and lateralward. To their margins are attached the capsules of the atlantoöccipital articulations, and on the medial side of each is a rough impression or tubercle for the alar ligament. At the base of either condyle the bone is tunnelled by a short canal, the hypoglossal canal (anterior condyloid foramen).

Altogether, sex specific tuning differences in the primary auditory neurons of the basilar papilla and duration sensitive cells in the torus semicircularis of males suggest a mechanism to explain the sex specific response behavior observed in E. coqui. Like sex differences in the olfactory system of M. sexta, and in the visual system of Bibionids, sex differences in the auditory system of E. coqui benefit receivers at a functional level by maximizing sensitivity to aggressive or mate attraction signals based on the sex of the receiver and which signal is relevant. In all three systems, the sensory systems of males and females are differently adapted to receive signals that are biologically useful and beneficial to survival or reproduction.

The place theory is usually attributed to Hermann Helmholtz, though it was widely believed much earlier. Experiments to distinguish between place theory and rate theory are difficult to devise, because of the strong correlation: large vibrations with low rate are produced at the apical end of the basilar membrane while large vibrations with high rate are produced at the basal end. The two can be controlled independently using cochlear implants: pulses with a range of rates can be applied via electrodes distributed along the membrane. Experiments using implant recipients showed that, at low stimulation rates, ratings of pitch on a pitch scale were proportional to the log of stimulation rate, but also decreased with distance from the round window.

A complex sound is split into different frequency components and these components cause a peak in the pattern of vibration at a specific place on the cilia inside the basilar membrane within the cochlea. These components are then coded independently on the auditory nerve which transmits sound information to the brain. This individual coding only occurs if the frequency components are different enough in frequency, otherwise they are in the same critical band and are coded at the same place and are perceived as one sound instead of two.Moore, B.C.J. (1986) Frequency Selectivity in Hearing, London, Academic Press The filters that distinguish one sound from another are called auditory filters, listening channels or critical bandwidths.

The tectorial membrane of atlanto-axial joint (occipitoaxial ligaments) is situated within the vertebral canal. D: Tectorial membrane of atlanto-axial joint It is a broad, strong band which covers the dens of the axis, and its ligaments, and appears to be a prolongation upward of the posterior longitudinal ligament of the vertebral column. It is fixed, below, to the posterior surface of the body of the axis, and, expanding as it ascends, is attached to the basilar groove of the occipital bone, in front of the foramen magnum, where it blends with the cranial dura mater. Its anterior surface is in relation with the transverse ligament of the atlas, and its posterior surface with the dura mater.

Zolmitriptan should not be given to patients with ischemic heart disease (angina pectoris, history of myocardial infarction, or documented silent ischemia) or to patients who have symptoms or findings consistent with ischemic heart disease, coronary artery vasospasm, including Prinzmetal's angina, or other significant underlying cardiovascular disease. Zolmitriptan may increase blood pressure, it should not be given to patients with uncontrolled hypertension, should not be used within 24 hours of treatment with another 5-HT1 agonist, or an ergotamine-containing or ergot-type medication like dihydroergotamine or methysergide, and should not be administered to patients with hemiplegic or basilar migraine. Concurrent administration of MAOI or use of zolmitriptan within 2 weeks of discontinuation of MAO-A inhibitor therapy is contraindicated.

On May 12, 2000, in a practice session for the Busch 200 race at New Hampshire Motor Speedway, Petty's throttle stuck wide open going into turn three, causing the car to hit the outside wall virtually head on. Petty was killed instantly when he suffered a basilar skull fracture. He was 19 years old. Petty's death, along with 1998 Winston Cup Rookie of the Year Kenny Irwin Jr.'s in the same corner at the same track eight weeks later, led NASCAR to mandate the use of a kill switch on the steering wheel and the adoption of the Whelen Modified Tour restrictor plate for the September Cup race; the plate was abandoned after that race.

From this theory, he developed a hypothesis about "the anatomical and physiological properties of the ear" where the assumption was that "the inner ear is a hydraulic system, that the effective cochlear oscillations occur in the basilar membrane, that this membrane is inelastic, and that its motions passively follow the motions of the stapes". This received little attention until the year 1966. After having a falling out with Stumpf, he migrated to London and spent time in the psychological lab of James Sully at the University of London for 6 months. Here he worked on developing an apparatus where a deaf person could even compose, as well as worked on a theory of harmony.

Besides research studies seeking to improve hearing, such as the ones listed above, research studies on the deaf have also been carried out in order to understand more about audition. Pijil and Shwarz (2005) conducted their study on the deaf who lost their hearing later in life and, hence, used cochlear implants to hear. They discovered further evidence for rate coding of pitch, a system that codes for information for frequencies by the rate that neurons fire in the auditory system, especially for lower frequencies as they are coded by the frequencies that neurons fire from the basilar membrane in a synchronous manner. Their results showed that the subjects could identify different pitches that were proportional to the frequency stimulated by a single electrode.

Both the HANS and Hutchens devices are designed to restrict "forward whipping of the head" due to the change in velocity during an impact, which can lead to a fatal basilar skull fracture. In a crash, the straps of the Hutchens device tighten as the driver's head begins to move forward, and use the driver's pelvic area as an anchor to prevent whipping of the head and neck. When first introduced, many drivers gravitated to the Hutchens device, due to greater comfort and range of movement over the HANS device. The Hutchens device was also more affordable than the HANS device, as the Hutchens was priced at less than $500 while the price for the HANS could run as high as $2,000.

Earnhardt Sr. was pronounced dead at 5:16 pm due to a basilar skull fracture. In the aftermath, many disgruntled fans sent death threats to Marlin and his family, blaming him for the crash; Earnhardt Jr. and Waltrip both requested that fans stopped blaming anybody for Earnhardt Sr.'s death and both the local police and NASCAR investigations into the crash cleared Marlin of any involvement. Earnhardt Jr. raced at Rockingham the following weekend, but finished in 43rd-place after a wreck on the first lap that looked eerily similar to his father's wreck just a week earlier. Returning to Daytona for the Pepsi 400, Earnhardt Jr. made a comeback and had the dominant car of the race, leading 115 out of 160 laps.

After exclusion of neck or head injury, observation should be continued for several hours. If repeated vomiting, worsening headache, dizziness, seizure activity, excessive drowsiness, double vision, slurred speech, unsteady walk, or weakness or numbness in arms or legs, or signs of basilar skull fracture develop, immediate assessment in an emergency department is needed. Observation to monitor for worsening condition is an important part of treatment. People may be released after assessment from hospital or emergency room to the care of a trusted person with instructions to return if they display worsening symptoms or those that might indicate an emergent condition ("red flag symptoms") such as change in consciousness, convulsions, severe headache, extremity weakness, vomiting, new bleeding or deafness in either or both ears.

Any simultaneous pair of partials of about the same amplitude that is less than a critical bandwidth apart produces roughness associated with the inability of the basilar membrane to separate them clearly. Roughness is physiologically determined and therefore universal, but it is appraised differently in different musical styles. Some musical styles deliberately create large amounts of roughness for aesthetic effect (for example some polyphonic styles in the Balkans in which singers favor simultaneous second intervals) while others try to avoid roughness as much as possible or treat rough sounds in special ways (for example most tonal western music). In terms of psychophysics, several studies have been done involving a person’s ability to detect the differences between the weight and roughness of objects.

On 19 August, 43-year-old Gennady Shutov died in the Minsk military hospital after he had received a gunshot to his head during the 11 August protests in Brest; reportedly, the shot was fired by the police. On 3 October, Denis Kuznetsov, a 41-year-old male who was detained on 29 September, died in an intensive care unit after being transported there from Okrestina. According to Kuznetsov's relatives and his medical history, during transportation to the hospital, he informed the medics that he was beaten by the Okrestina staff, who, in turn, claimed that Kuznetsov "fell from the top of a bunk bed". The Kuznetsov's clinical diagnosis, among other things, included moderate traumatic brain injury, numerous hematomas, basilar skull fracture, subarachnoid hemorrhage and fractures of 11 right ribs.

The success of a cochlear implant relies in part upon electrode array placement within the cochlea in which the positioning is based on the frequency-spatial relationship empirically described by the Greenwood function. By aligning the electrodes with the positions of the auditory ganglia contacting the basilar membrane as described by the Greenwood function, the cochlear implant electrode array stimulates auditory ganglia associated with the reception of frequencies associated with speech recognition. Electrode array insertion depth is guided by the frequency map created by the Greenwood function, and allows electrical stimulation of neurons involved in stimulating the area of the brain responsible for speech recognition while minimizing ganglia stimulation in noise-generating regions. Well-placed electrode arrays in patients receiving cochlear implants can allow otherwise deafened auditory systems to achieve hearing and recognize speech.

The reason the ABR does not identify small tumors can be explained by the fact that ABRs rely on latency changes of peak V. Peak V is primarily influenced by high-frequency fibers, and tumors will be missed if those fibers aren't affected. Although the click stimulates a wide frequency region on the cochlea, phase cancellation of the lower-frequency responses occurs as a result of time delays along the basilar membrane. If a tumor is small, it is possible those fibers won't be sufficiently affected to be detected by the traditional ABR measure. Primary reasons why it is not practical to simply send every patient in for an MRI are the high cost of an MRI, its impact on patient comfort, and limited availability in rural areas and third-world countries.

Many sounds in everyday life, including speech and music, are broadband; the frequency components spread over a wide range and there is no well-defined way to represent the signal in terms of ENVp and TFSp. However, in a normally functioning cochlea, complex broadband signals are decomposed by the filtering on the basilar membrane (BM) within the cochlea into a series of narrowband signals. Therefore, the waveform at each place on the BM can be considered as an envelope (ENVBM) superimposed on a more rapidly oscillating carrier, the temporal fine structure (TFSBM). The ENVBM and TFSBM depend on the place along the BM. At the apical end, which is tuned to low (audio) frequencies, ENVBM and TFSBM vary relatively slowly with time, while at the basal end, which is tuned to high frequencies, both ENVBM and TFSBM vary more rapidly with time.

The next day, in qualifying, Simtek driver Roland Ratzenberger crashed at the Villeneuve Corner after his front wing, which he damaged on his first qualifying lap, broke off and Ratzenberger, unable to steer the car into the corner, crashed almost head on into a retaining wall close to the track at nearly 195 mph, suffered a basilar skull fracture and was killed. Then finally, on race day, Benetton driver JJ Lehto and Lotus driver Pedro Lamy collided at the start, with debris flying over the fences injuring eight spectators. Then, on Lap 7, Williams driver Ayrton Senna after a possible mechanical issue with his car, ran off course at the high- speed Tamburello. Senna first came off the track at 325 km/h (195 mph), downshifting twice to 225 km/h (135 mph) before colliding with the wall.

The pontine tegmentum contains nuclei of the cranial nerves (trigeminal (5th), abducens (6th), facial (7th), and vestibulocochlear (8th) cranial nerve nuclei) and their associated fibre tracts, the tegmental pontine reticular nucleus, the mesopontine cholinergic system comprising the pedunculopontine nucleus and the laterodorsal tegmental nucleus, and in the respiratory center the pontine respiratory group – the pneumotaxic centre and the apneustic centre. Nearby important structures include the cranial nerve nuclei of the oculomotor (3rd) and trochlear (4th) nerve nuclei, which are located in the midbrain, the pontine nuclei, which are located within the basilar pons, and the raphe nucleus and the locus ceruleus, nuclei of cranial nerves 9-12, and the dorsal respiratory group, which are located further caudally in the brainstem. The dorsal respiratory group are connected to the pneumotaxic and apneustic centres of the pontine tegmentum.

However, they often lack a basilar papilla, having instead an entirely separate set of sensory cells at the upper edge of the saccule, referred to as the papilla amphibiorum, which appear to have the same function. Although many fish are capable of hearing, the lagena is, at best, a short diverticulum of the saccule, and appears to have no role in sensation of sound. Various clusters of hair cells within the inner ear may instead be responsible; for example, bony fish contain a sensory cluster called the macula neglecta in the utricle that may have this function. Although fish have neither an outer nor a middle ear, sound may still be transmitted to the inner ear through the bones of the skull, or by the swim bladder, parts of which often lie close by in the body.

Other differences in head shape between brachycephalic and dolichocephalic dogs include changes in the craniofacial angle (angle between the basilar axis and hard palate) (Regodón 1993), morphology of the temporomandibular joint (Dickie 2001), and radiographic anatomy of the cribriform plate (Schwarz 2000). Nowak indicated that orbital angle of the eye socket is an important characteristic defining the difference between the dog and the wolf, with the wolf having the lower angle. Nowak compared the orbital angles of four North American canines (including the Indian dog) and produced the following values in degrees: coyote-42.8, wolf-42.8, dog-52.9 dire wolf-53.1. The orbital angle of the eye socket was clearly larger in the dog than in the coyote and the wolf; why it was almost the same as that of the dire wolf was not commented on.

These two adjustments addressed the cause of the deadly accidents, but did not address the basilar skull fractures suffered by both drivers. At Texas Motor Speedway, Truck Series driver Tony Roper died on October 14, 2000 of a similar head injury. Mandatory use of the HANS or Hutchens device (designed to prevent the rapid-deceleration head-and-neck movements associated with the injuries associated with the Petty, Irwin, Jr., and Roper deaths) was mandated by NASCAR in October 2001, months after seven-time Winston Cup champion Dale Earnhardt died of the same injury on the last lap of the Daytona 500 on February 18, 2001. Adam's father Kyle Petty, who drove the No. 44 car at the time of his son's fatal crash, drove Adam's No. 45 car in the Busch Series for the remainder of 2000.

Bruises are not to be confused with other similar-looking lesions. These lesions include petechia (< 3 mm result from numerous and diverse etiologies such as adverse reactions from medications such as warfarin, straining, asphyxiation, platelet disorders and diseases such as cytomegalovirus), purpura (3 mm to 1 cm, classified as palpable purpura or non-palpable purpura and indicates various pathologic conditions such as thrombocytopenia), and ecchymosis (>1 cm caused by blood dissecting through tissue planes and settled in an area remote from the site of trauma or pathology such as periorbital ecchymosis, e.g.,"raccoon eyes", arising from a basilar skull fracture or from a neuroblastoma). As a type of hematoma, a bruise is always caused by internal bleeding into the interstitial tissues which does not break through the skin, usually initiated by blunt trauma, which causes damage through physical compression and deceleration forces.

A short time later, Weylandt's body was airlifted off the descent and taken to a nearby hospital, where the pathologist conducting the autopsy concluded that the Belgian had sustained a basilar skull fracture, and had died immediately upon crashing. Weylandt's death was the first at the Giro in 25 years, and the first at one of cycling's Grand Tours since Fabio Casartelli died during the 1995 Tour de France. Manuel Antonio Cardoso of had been nearest to Weylandt when he crashed, and stated that Weylandt had touched a small retaining wall on the left side of the road with either his pedal or his handlebars, and was then catapulted across the road to the other side, where he again collided with something. He had looked behind him to ascertain his exact position in the race when he clipped the wall.

Physiologically, each spectral pitch depends on both temporal and spectral aspects (i.e. periodicity of the waveform and position of excitation on the basilar membrane), but in Terhardt's approach the spectral pitch itself is a purely experiential parameter, not a physical parameter: it is the outcome of a psychoacoustical experiment in which the conscious listener plays an active role. Psychoacoustic measurements and models can predict which partials are "perceptually relevant" in a given complex tone; they are perceptually relevant if you can hear a difference in the whole sound if the frequency or amplitude of a partial is changed). The ear has evolved to separate spectral frequencies, because due to reflection and superposition in everyday environments spectral frequencies are more reliably carriers of environmental information than spectral amplitudes, which in turn are more reliable carriers of environmentally relevant information than phase relationships between partials (when perceived monoaurally).

Those of the basilar artery and posterior cerebral artery are hard to reach surgically and are more accessible for endovascular management. These approaches are based on general experience, and the only randomized controlled trial directly comparing the different modalities was performed in relatively well people with small (less than 10 mm) aneurysms of the anterior cerebral artery and anterior communicating artery (together the "anterior circulation"), who constitute about 20 percent of all people with aneurysmal SAH. This trial, the International Subarachnoid Aneurysm Trial (ISAT), showed that in this group the likelihood of death or being dependent on others for activities of daily living was reduced (7.4 percent absolute risk reduction, 23.5 percent relative risk reduction) if endovascular coiling was used as opposed to surgery. The main drawback of coiling is the possibility that the aneurysm will recur; this risk is extremely small in the surgical approach.

12(S)-HETE and 12(S)-HpETE stimulate the dilation of rat mesenteric arteries; 12(S)-HETE stimulates the dilation of coronary microvessels in pigs and the mesenteric arteries of mice, one or more of these three metabolites are implicated in the vasodilation of rat basilar artery, 12(R)-HETE and to a slightly lesser extent 12(S)-HETE constrict the renal artery of dogs and 12-HETE (stereoisomer undetermined) is implicated in the angiotensin II-induced arterial hypertension response of human placenta. The vasodilating effect on mouse mesenteric arteries appears due to 12S-HETE's ability to act as a Thromboxane receptor antagonist and thereby block the vasoconstricting actions of thromboxane A2. These results indicate that the cited metabolites have dilating or constricting effects that depend on the arterial vascular site and or species of animal examined; their role in human blood pressure regulation is unclear.

McDuffie's death was among the catalysts that led to increased funding by the automakers to continue research into basilar skull fractures as part of motorsport safety improvements, as adoption by sports car drivers of HANS had increased. By the end of the decade, following two CART fatalities in one season and three NASCAR fatalities in a span of five months, and then the start of the next decade with two more fatalities (including that of Dale Earnhardt, Sr.), and research into the head and neck restraints that had quickly been adopted, most motorsport sanctioning bodies mandated head and neck restraints worldwide. McDuffie's widow, Ima Jean, unsuccessfully sued Watkins Glen for $4.25 million, claiming the barrier McDuffie hit was unsafe. The judge in that case ruled that McDuffie was familiar enough with the track to be aware of the dangers and that mechanical failure caused the accident.

Normally, vibrations of the tympanic membrane (eardrum) elicited by acoustic stimuli are transmitted through the chain of ossicles (malleus, incus, and stapes) in the middle ear to the oval window of the cochlea. Vibrations of the footplate of stapes transmit through the oval window to the perilymph, which in turn causes the endolymph, the basilar membrane, and the organ of Corti to vibrate, activating ultimately the acoustic sensor cells, the inner hair cells of the organ of Corti. The transfer function of this complex mechanical system under physiological conditions is modulated by the action of two small muscles of the middle ear, the tensor tympani, and stapedius. The tensor tympani arises from the cartilaginous portion of the auditory tube and the osseous canal of the sphenoid and, having sharply bent over the extremity of the septum, attaches to the manubrium of the malleus (hammer); its contraction pulls the malleus medially, away from the tympanic membrane, which tenses the membrane.

His funeral was held four days later at the Calvary Church in Charlotte, North Carolina. Earnhardt was the fourth NASCAR driver killed by a basilar skull fracture during an eight-month span, following Adam Petty in May 2000, Kenny Irwin Jr. in July 2000, and Tony Roper in October 2000\. Earnhardt's death, seen on a live television broadcast with more than 17 million viewers, was highly publicized and resulted in various safety improvements in NASCAR auto racing.Dale Earnhardt's last gift 5 years after the crash, That's Racin After Earnhardt's death, NASCAR began an intensive focus on safety that has seen the organization mandate the use of head-and-neck restraints, oversee the installation of SAFER barriers at oval tracks, set rigorous new inspection rules for seats and seat-belts, develop a roof-hatch escape system, and the Car of Tomorrow—which eventually led to the development of a next-generation race car built with extra driver safety in mind.

The anterior boundary of the sella turcica is completed by two small eminences, one on either side, called the middle clinoid processes, while the posterior boundary is formed by a square-shaped plate of bone, the dorsum sellae, ending at its superior angles in two tubercles, the posterior clinoid processes, the size and form of which vary considerably in different individuals. The posterior clinoid processes deepen the sella turcica, and give attachment to the tentorium cerebelli. On either side of the dorsum sellae is a notch for the passage of the abducent nerve, and below the notch a sharp process, the petrosal process, which articulates with the apex of the petrous portion of the temporal bone, and forms the medial boundary of the foramen lacerum. Behind the dorsum sellae is a shallow depression, the clivus, which slopes obliquely backward, and is continuous with the groove on the basilar portion of the occipital bone; it supports the upper part of the pons.

One year later, Joey Logano became the youngest winner in NASCAR Cup Series history after the race was also shortened because of rain after 273 laps, at the age of 19 years, 1 month, and 4 days. Starting in 2018, it will be the only event at the track because their fall race would be moved to Las Vegas Motor Speedway. During the practice for the 2000 event, Kenny Irwin Jr. was killed after he lost control of his car, which slammed head on into the wall, causing it to flip onto its side. His cause of death, basilar skull fracture, was the same cause that killed Busch Series driver Adam Petty eight weeks prior at Busch 200 at the same track, leading NASCAR to make significant rule changes to maintain driver safety, including an experiment on using a restrictor plate for the next New Hampshire Cup race that season, the Dura Lube 300.

It is concave in front, convex behind, broader and thicker in the middle than at the ends, and firmly attached on either side to a small tubercle on the medial surface of the lateral mass of the atlas.Gray's anatomy, 1918 As it crosses the odontoid process, a small fasciculus (crus superius) is prolonged upward, and another (crus inferius) downward, from the superficial or posterior fibers of the ligament. The former is attached to the basilar part of the occipital bone, in close relation with the membrana tectoria; the latter is fixed to the posterior surface of the body of the axis; hence, the whole ligament is named the cruciate ligament of the atlas. The transverse ligament divides the ring of the atlas into two unequal parts: of these, the posterior and larger serves for the transmission of the medulla spinalis and its membranes and the accessory nerves; the anterior and smaller contains the odontoid process.

Experiments to distinguish between place theory and rate theory using subjects with normal hearing are difficult to devise, because of the strong correlation between rate and place: large vibrations at a low rate are produced at the apical end of the basilar membrane while large vibrations at a high rate are produced at the basal end. The two stimulus parameters can, however, be controlled independently using cochlear implants: pulses with a range of rates can be applied via different pairs of electrodes distributed along the membrane and subjects can be asked to rate a stimulus on a pitch scale. Experiments using implant recipients (who had previously had normal hearing) showed that, at stimulation rates below about 500 Hz, ratings on a pitch scale were proportional to the log of stimulation rate, but also decreased with distance from the round window. At higher rates, the effect of rate became weaker, but the effect of place was still strong.

Though not recognized at the time, many racing safety experts have concluded that Evans' death resulted from the same type of "head-whip" injury and resultant Basilar skull fracture, which also claimed the life of Dale Earnhardt in 2001. Evans was the father of six children: Jodi Lynn (Evans) Meola, Janelle Ralaine (Evans) Walda, Jill Ann Evans, Jacqueline Marie (Evans) Williams, Richard Edwin Evans (who has raced under the moniker "Richie Evans Jr.") and Tara Denise (Evans) Farrell. Evans' signature orange Modified paint scheme (GMC truck color Omaha Orange; black numbers with white shading) was replicated in 2003 on a Busch Series car driven by New Jersey native Martin Truex, Jr. in his first year on the series driving for Dale Earnhardt, Jr.'s Chance 2 Motorsports. Steve Park also ran a Richie Evans tribute paint scheme for Tommy Baldwin Racing's No. 36 entry at the 2010 Coke Zero 400 at Daytona.

Six weeks earlier, Camel GT prototype driver Tommy Kendall had a hard crash in the same section during the Camel Continental VIII, when a wheel failed on his Pratt & Miller Intrepid RM-1-Chevrolet prototype, sliding into the barrier, breaking both his legs and sidelining him for the rest of the 1991 season, including the Winston Cup race, where he was set to substitute for Kyle Petty, injured at Talladega in May (Kendall had substituted for Petty at Sears Point earlier in the year). The track was then given a bus stop chicane placed slightly before the entrance of turn five, the section of track in question, and a gravel trap (since paved over after research into motorsport safety proved the advantage of a tarmac runoff), for the 1992 season. Also, at the time, basilar skull fractures were the subject of developing research by Jim Downing and Bob Hubbard into a head and neck restraint for motorsport. Downing, a champion sports car racer, and his brother-in-law Hubbard, were in the process of developing the HANS device, which had just begun production.

In humans, sound waves funnel into the ear via the external ear canal and reach the eardrum (tympanic membrane). The compression and rarefaction of these waves set this thin membrane in motion, causing sympathetic vibration through the middle ear bones (the ossicles: malleus, incus, and stapes), the basilar fluid in the cochlea, and the hairs within it, called stereocilia. These hairs line the cochlea from base to apex, and the part stimulated and the intensity of stimulation gives an indication of the nature of the sound. Information gathered from the hair cells is sent via the auditory nerve for processing in the brain. The commonly stated range of human hearing is 20 to 20,000 Hz.20 to 20,000 Hz corresponds to sound waves in air at 20°C with wavelengths of 17 meters to 1.7 cm (56 ft to 0.7 inch). Under ideal laboratory conditions, humans can hear sound as low as 12 Hz and as high as 28 kHz, though the threshold increases sharply at 15 kHz in adults, corresponding to the last auditory channel of the cochlea.

Several indirect measurements on CT can be used to assess ligamentous integrity at the craniocervical junction. The Wackenheim line, a straight line extending along the posterior margin of the clivus through the dens, should not intersect the dens on plain film, with violation of this relationship raising concern for basilar invagination. The basion to axion interval, or BAI, is also used, which is determined by measuring the distance between an imaginary vertical line at the anterior skull base, or basion, at the foramen magnum, and the axis of the cervical spine along its posterior margin, which should measure 12 mm, an assessment more reliable on radiograph than CT. The distance between the atlas and the occipital condyles, the atlanto-occipital interval (AOI), should measure less than 4 mm, and is better assessed on coronal images. The distances between the dens and surrounding structures are also key features that can suggest the diagnosis, with the normal distance between the dens and basion (BDI) measuring less than 9 mm on CT, and the distance between the dens and atlas (ADI) measuring less than 3 mm on CT, although this can be increased in cases of rheumatoid arthritis due to pannus formation.