Bicolored, widowed,male by male, dragged Caudally, reclusivelyinto jellyfish and coelenterates, Anemones brimming overwith pearly powder, uncertainty's Nectar and fear floatingbetween cold water and heat of lip.
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Specimen 1912VIII64 was opisthocoelous, pleurocoelous, and caudally wider than tall, as in Epachthosaurus and Pellegrinisaurus, and may pertain to Paralititan.
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As in Archaeopteryx, the skull of Sinornis has a proportionately short, toothed snout. There are broad nasal bones that expands caudally to the external nares, with a triangular caudal margin. The dorsal and central margins of the caudal half of the maxilla run parallel while its jugal ramus does not taper caudally. The postcranial skeleton features a separate carpus and manus in the forelimb.
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Collar bones are very much reduced, and one incisor, one premolar and three molars are present in each quadrant. The male's penis is directed caudally when not erect.
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All juvenile and most adult specimens have gently recurved anterior and posterior margins resulting in most horns having an apex that is oriented at least slightly caudally (backwards).
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Thus, it is bounded caudally by the inferior precentral sulcus (H) and rostrally by the anterior ascending limb of lateral sulcus (H). It surrounds the diagonal sulcus (H). In the depth of the lateral sulcus it borders on the insula. Cytoarchitectonically it is bounded caudally and dorsally by the agranular frontal area 6, dorsally by the granular frontal area 9 and rostrally by the triangular part of inferior frontal gyrus (Brodmann area 45 BA 45).
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This results in a "bundle"-like structure of nerve fibers that extends caudally from the end of the spinal cord, gradually declining in number further down as individual pairs leave the spinal column.
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Cytoarchitecturally it is bounded medially by the ectorhinal area 36 (H), laterally by the middle temporal area 21, rostrally by the temporopolar area 38 (H) and caudally by the occipitotemporal area 37 (H) (Brodmann-1909).
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In the outer part of the intermediate mesoderm, immediately under the ectoderm, in the region from the fifth cervical segment to the third thoracic segment, a series of short evaginations from each segment grows dorsally and extends caudally, fusing successively from before backward to form the pronephric duct. This continues to grow caudally until it opens into the ventral part of the cloaca; beyond the pronephros it is termed the mesonephric duct. Thus, the mesonephric duct remains after the atrophy of the pronephros duct.
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The holotype is a nearly complete caudally located cervical vertebra (a cervical vertebra located near the base of the neck), specimen number IPS SRA-1. Another cervical, a humerus, and an ulna were designated the paratype specimens.
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In the outer part of the intermediate mesoderm, immediately under the ectoderm, in the region from the fifth cervical segment to the third thoracic segment, a series of short evaginations from each segment grows dorsally and extends caudally, fusing successively from before backward to form the pronephric duct. This continues to grow caudally until it opens into the ventral part of the cloaca; beyond the pronephros it is termed the Wolffian duct. Thus, the Wolffian duct is what remains of the pronephric duct after the atrophy of the pronephros.
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In mammals, the Bötzinger complex (BötC) is a group of neurons located in the rostral ventrolateral medulla, and ventral respiratory column. In the medulla, this group is located caudally to the facial nucleus and ventral to nucleus ambiguus.
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It is innervated by the accessory nerve. Sternohyoideus: originates on the sternum and inserts on the basihyoid bone. Its function is to move the tongue caudally. It is innervated by the ventral branches of the cervical spinal nerves.
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Cytoarchitecturally it is bounded rostrally by the ventral anterior cingulate area 24, ventrally by the ventral posterior cingulate area 23, dorsally by the gigantopyramidal area 4 and preparietal area 5 and caudally by the superior parietal area 7 (H) (Brodmann-1909).
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All species within this order have specialized forelimbs and a center of gravity shifted caudally towards the pelvis from other quadrupeds, but rostrally when compared to fully bipedal humans. The lumbar vertebrae are said to be xenarthrous, the eponymous characteristic of the magnorder, and that means that they come into contact with each other at more points to stabilize the pelvis and the bulk of the caudally shifted mass. It would have been unable to gallop. In humans, pelvic bones are not fused together in a solid block, and this allows us greater variability of motion from side to side.
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In terms of cytoarchitecture, it is bounded caudally by the opercular part of inferior frontal gyrus (Brodmann area 44 (BA44)), rostrodorsally by the middle frontal area 46 (BA46), and ventrally by the orbital part of inferior frontal gyrus (Brodmann area 47 BA47).
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It is bounded dorsally approximately by the intraparietal sulcus. In terms of its cytoarchitecture, it is bounded rostrally by the supramarginal area 40 (H), dorsally and caudally by the peristriate area 19, and ventrally by the occipitotemporal area 37 (H) (Brodmann-1909).
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587 Pp. Smithsonian Institution Press, , Birds and reptiles have bony uncinate processes on their ribs that project caudally from the vertical section of each rib. These serve to attach sacral muscles and also aid in allowing greater inspiration. Crocodiles have cartilaginous uncinate processes.
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The cheeks are covered externally by hairy skin, and internally by stratified squamous epithelium. This is mostly smooth, but may have caudally directed papillae (e.g., in ruminants). The mucosa is supplied with secretions from the Buccal glands, which are arranged in superior and inferior groups.
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The CNS consists of the two major structures: the brain and spinal cord. The brain is encased in the skull, and protected by the cranium. The spinal cord is continuous with the brain and lies caudally to the brain. It is protected by the vertebrae.
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The tendon is reflected caudally, laterally, and inferiorly beneath the superior rectus to the lateral part of the bulb of the eye, and is inserted onto the scleral surface, behind the equator of the eyeball, the insertion of the muscle lying between the superior rectus and lateral rectus.
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Group A8 is a small group of dopaminergic cells in rodents and primates. It is located in the midbrain reticular formation dorsolateral to the substantia nigra at the level of the red nucleus and caudally. In the mouse it is identified with the retrorubral field as defined by classical stains.
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Brainstem (dorsal view). A:Thalamus B:Midbrain C:Pons D:Medulla oblongata 7 and 8 are the colliculi. The principal regions of the midbrain are the tectum, the cerebral aqueduct, tegmentum, and the cerebral peduncles. Rostrally the midbrain adjoins the diencephalon (thalamus, hypothalamus, etc.), while caudally it adjoins the hindbrain (pons, medulla and cerebellum).
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Sternothyoideus: originates on the first coastal cartilage and inserts on the thyroid cartilage. Its function is also to move the tongue caudally. It is innervated by the ventral branches of the cervical spinal nerves. Omotransversarius: originates on the spine of the scapula and inserts on the wing of the atlas.
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This is reported to cause collateral flow paths to open up to drain the left kidney i.e. reversed flow (reflux caudally) in the left renal vein. Pelvic Congestion Syndrome, vaginal and vulval varices, lower limb varices are clinical sequelae. Virtually all such patient are female and have been pregnant, often multiply.
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Archaeichnium also has latitudinal restrictions that organize it into approximately three sections cranio-caudally. When cross-sectioned, the tube lacks septae. The fossil is typically found in cross-bedded sandstone that is interpreted as a shallow marine depositional environment. Walls of the tube are typically agglutinated with small quartz grains.
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The intermediate mesoderm connects the paraxial mesoderm with the lateral plate and differentiates into urogenital structures. In upper thoracic and cervical regions this forms the nephrotomes, and in caudally regions this forms the nephrogenic cord. It also helps to develop the excretory units of the urinary system and the gonads.
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One autapomorphy (unique characteristic) of Ratchasimasaurus is its elongated and flat ramus of the dentary. Ratchasimasaurus shows both primitive and derived characters for Iguanodontia, such as "a caudally inclined coronoid process and alveolar trough with a primitive crown impression, and a derived buccal shelf between the tooth row and the coronoid process".
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All inputs into the VB are contralateral and have two different receptive fields within the VB. The VPM receptive field receives input from the contralateral trigeminal nerve and the VPL receptive field receives input from the contralateral spinal nerve. Each have NS and WDR neurons but terminate either caudally or rostrally respectively.
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There are four different orientations for the coccyx, as described by Postacchini and Massobrio. In type I the coccyx is curved anteriorly with its apex facing downward and caudally. In type II this forward curvature is more dramatic and the apex extends forward. Type III is where the coccyx angles forward sharply.
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The specific rhombomeres from which the cerebellum forms are rhombomere 1 (Rh.1) caudally (near the tail) and the "isthmus" rostrally (near the front). Two primary regions are thought to give rise to the neurons that make up the cerebellum. The first region is the ventricular zone in the roof of the fourth ventricle.
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It also possesses one to three Y-shaped dark bands in the posterior portion of the body. Interband contrast increases ventrally and caudally, and is particularly pronounced in small specimens. The anterior 80% of its dorsum is without banding. Three bands from either side meet on its ventral midline, between the anus and anal fin.
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Prefrontal and agranular cingulate projections to the dorsal premotor areas F2 and F7 in the macaque monkey (Fig. 3). European Journal of Neuroscience, 17(3), 559-578. Based on single unit recording and microstimulation it has been established that the SEF is caudally contiguous with the parts of the SMA which represent orofacial, and forelimb movements.Schall, J. D. (1991).
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Group A15 exists in a few species, such as sheep, and immunoreactive for tyrosine hydroxylase, a precursor of dopamine, in many other species including rodents and primates. It is located in ventral and dorsal components within the preoptic periventricular nucleus and adjacent parts of the anterior hypothalamic region. It is continuous caudally with the dopaminergic group A14.
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This continues both cranially (toward the head) and caudally (toward the tail). The openings that are formed at the cranial and caudal regions are termed the cranial and caudal neuropores. In human embryos, the cranial neuropore closes approximately on day 24 and the caudal neuropore on day 28.Youman's Neurological Surgery, H Richard Winn, 6th ed.
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Cheesewiring is commonly used in the endovascular repair. The cheesewire technique can be used to fenestrate an intimal flap, alleviating malperfusion in aortic dissection. Pulling both ends of a guide wire in a caudally sawing motion down through the infrarenal neck and into the aneurysm sac completes the technique. This process shears the flap with minimal damage.
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Ancorae present, with bulbous swelling when viewed dorso-caudally narrowing to an inwardly directed point. Dorsal sclerite well developed as in other members of this genus, with broad lateral arms converging to form a broad, blunt, upturned projection with swelling at apex projecting caudal. Large swollen shell-shaped supraramus closely flanking the aedeagus. Dorsal aedeagal sclerites large and swollen, ventral aedeagal sclerites long.
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The ventral tegmental area is in the midbrain between several other major areas, some of which are described here. The mammillary bodies and the posterior hypothalamus, both included in the diencephalon, extend rostrally from the VTA. The red nucleus is situated laterally and oculomotor fibers are situated ventromedially to the VTA. The pons and the hindbrain lie caudally to the VTA.
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The alar fascia is a layer of fascia, sometimes described as part of the prevertebral fascia, and sometimes as in front of it. Cranially, it reaches the skull, and caudally, it reaches the second thoracic vertebra. It is the posterior border of the retropharyngeal space. In 2015, the anatomy of the alar fascia was revisited using dissection in conjunction with E12 plastination.
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The diaphragm is the major muscle responsible for breathing. It is a thin, dome-shaped muscle that separates the abdominal cavity from the thoracic cavity. During inhalation, the diaphragm contracts, so that its center moves caudally (downward) and its edges move cranially (upward). This compresses the abdominal cavity, raises the ribs upward and outward and thus expands the thoracic cavity.
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In the human brain, the entorhinal cortex appears as a longitudinal elevation anterior to the parahippocampal gyrus, with a corresponding internal furrow, the external rhinal sulcus (or rhinal fissure), separating it from the inferiolateral surface of the hemisphere close to the lamina terminalis. It is analogous to the collateral fissure found further caudally in the inferior part of the temporal lobe.
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There are two types of nociceptive neurons that provide input to the VB: nociceptive specific (NS) neurons and wide dynamic range neuron (WDR). NS neurons respond specifically to a noxious mechanical stimulus, whereas WDR neurons respond to a graded mechanical stimulus. NS and WDR neurons within the VB are somatotopically organized. NS neurons are located more caudally in the VB, while WDR neurons are located more rostrally.
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Brindled madtoms are approximately long. The brindled madtom, like other Noturus species, has a caudally-fused adipose fin which extends from the caudal fin and runs nearly to the dorsal fin. The caudal fin spreads around the caudal peduncle, terminating just prior to the anal fin. The species has smooth skin without scales and possesses four pairs of barbels along the premaxilla and dentary.
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Cytoarchitecturally it is bounded dorsally by the granular frontal area 9, caudally by the middle frontal area 46, and ventrally by the orbital area 47 and by the rostral area 12 or, in an early version of Brodmann's cortical map (Brodmann-1909), the prefrontal Brodmann area 11-1909. Area 10 lies on top of a bony air sinus which has limited Electrophysiology research upon it.
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With its medial boundary corresponding approximately to the rhinal sulcus it is located primarily in the fusiform gyrus. Cytoarchitecturally it is bounded laterally and caudally by the inferior temporal area 20, medially by the area 35 and rostrally by the temporopolar area 38 (H) (Brodmann-1909). Its function is part of the formation/consolidation and retrieval of declarative/hippocampal memory amongst others for faces.
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The perirhinal cortex is a cortical region in the medial temporal lobe that is made up of Brodmann areas 35 and 36. It receives highly processed sensory information from all sensory regions, and is generally accepted to be an important region for memory. It is bordered caudally by postrhinal cortex or parahippocampal cortex (homologous regions in rodents and primates, respectively) and ventrally and medially by entorhinal cortex.
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Since this is a dosage dependent gene, the different amounts of gene present in certain location can cause different outcomes. FGF8 is affected by the different dosages in the location it is expressed. The absence of GBX2 causes FGF8 expression is shifted caudally and over expression of GBX2 causes FGF8 expression to be shifted rostrally. Not all of the rhombomeres GBX2 is expressed in require the same strictness of dose regulation.
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Noradrenergic cell group A4 is a group of cells exhibiting noradrenergic fluorescence that, in the rat, are located in the Tegmen ventriculi quarti (roof of the fourth ventricle) ventral to the cerebellar nuclei, and in the macaque, are found at the edge of the lateral recess of the fourth ventricle caudally, extending to beneath the floor of the ventricle where they merge with the noradrenergic group A6, the locus ceruleus.
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Ventricular system anatomy showing the cerebral aqueduct, labelled centre right. The cerebral aqueduct is the part of the ventricular system which links the third ventricle (rostrally) with the fourth ventricle (caudally); as such it is responsible for continuing the circulation of cerebrospinal fluid. The cerebral aqueduct is a narrow channel located between the tectum and the tegmentum, and is surrounded by the periaqueductal grey,Martin. Neuroanatomy Text and Atlas, Second edition.
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Dentaries AENM 2/846 (A-B) and AENM 2/902 (C-D). Kundurosaurus is a saurolophine diagnosed by four autapomorphies, unique derived traits. It has a prominent and thick ridge on the lateral side of the nasal that borders caudally the circumnasal depression and invades the caudal plate of the nasal. Its caudal buttress of the proximal head of the scapula is oriented quite laterally, parallel to the pseudoacromial process.
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Jinguofortisidae is distinguished from other non-ornithothoracine birds by the following features: the scapula and coracoid fused into a scapulocoracoid; a boomeranged-shaped furcula without a hypocleidium; proximal margin of humerus concave centrally; deltopectoral crest large and not perforated; minor metacarpal markedly bowed caudally; alular digit terminating at the level of the distal end of major metacarpal; and proximal phalanx of the major digit longer than the intermediate phalanx.
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This area is also known as middle temporal area 21. It is a subdivision of the cytoarchitecturally defined temporal region of cerebral cortex. In the human it corresponds approximately to the middle temporal gyrus. It is bounded rostrally by the temporopolar area 38 (H), ventrally by the inferior temporal area 20, caudally by the occipitotemporal area 37 (H), and dorsally by the superior temporal area 22 (Brodmann-1909).
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It is located primarily in the caudal portions of the fusiform gyrus and inferior temporal gyrus on the mediobasal and lateral surfaces at the caudal extreme of the temporal lobe. Cytoarchitecturally, it is bounded caudally by the peristriate Brodmann area 19, rostrally by the inferior temporal area 20 and middle temporal area 21, and dorsally on the lateral aspect of the hemisphere by the angular area 39 (H) (Brodmann-1909).
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After inducing the metanephric mesenchyme the lower portions of the nephric duct will migrate caudally (downward) and connect with the bladder, thereby forming the ureters. The ureters will carry urine from the kidneys to the bladder for excretion from the fetus into the amniotic sac. As the fetus develops, the torso elongates and the kidneys rotate and migrate upwards within the abdomen which causes the length of the ureters to increase.
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The paramesonephric ducts are formed by the craniocaudal invagination of a ribbon of thickened coelomic epithelium that extends from the third thoracic segment caudally to the posterior wall of the urogenital sinus. The caudal parts of the paramesonephric ducts fuse into a single tube, known as the uterovaginal primordium, before flowing into the dorsal aspect of the urogenital sinus at the sinus tubercle directly medial to the mesonephric ducts.
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This process points dorsally and caudally from the junction of the laminae. The spinous process serves to attach muscles and ligaments. The two transverse processes, one on each side of the vertebral body, project from either side at the point where the lamina joins the pedicle, between the superior and inferior articular processes. They also serve for the attachment of muscles and ligaments, in particular the intertransverse ligaments.
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Brodmann area 31, also known as dorsal posterior cingulate area 31, is a subdivision of the cytoarchitecturally defined cingulate region of the cerebral cortex. In the human it occupies portions of the posterior cingulate gyrus and medial aspect of the parietal lobe. Approximate boundaries are the cingulate sulcus dorsally and the parieto-occipital sulcus caudally. It partially surrounds the subparietal sulcus, the ventral continuation of the cingulate sulcus in the parietal lobe.
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The AON plays a pivotal but relatively poorly understood role in the processing of odor information. Odors enter the nose (or olfactory rosette in fishes) and interact with the cilia of olfactory receptor neurons. The information is sent via the olfactory nerve (Cranial Nerve I) to the olfactory bulb. After the processing in the bulb the signal is transmitted caudally via the axons of mitral and tufted cells in the lateral olfactory tract.
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Averianov had in 2002 proposed three traits in which A. archibaldi differed from A. magnus. Its braincase has three exits for the Nervus hypoglossus (cranial nerve XII) instead of two. It also has a more limited angle of 90° between the ventral surfaces of the basioccipital and the basisphenoid, and more caudally, to the rear, situated basipterygoid processes. In 2004, these were no longer considered unique traits but the triple exits were seen as rare.
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Principal connections of the tectum The tectum (Latin for roof) is the dorsal side of the midbrain. The position of the tectum is contrasted with the tegmentum, which refers to the region in front of the ventricular system, or floor of the midbrain. It is involved in certain reflexes in response to visual or auditory stimuli. The reticulospinal tract, which exerts some control over alertness, takes input from the tectum, and travels both rostrally and caudally from it.
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Paguma larvata (Hamilton-Smith).. In: The Fauna of British India, Including Ceylon and Burma: Mammalia Volume 1. Taylor and Francis, London. The mask consists of a prominent white stripe stretching from nose to forehead (sometimes extends farther but has greatly reduced thickness) that halves a black mask that extends laterally to the far edges of the cheeks and caudally up the forehead, past the ears, and down the back of the neck before stopping just under the shoulder blades.
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The development of the pronephric duct proceeds in a cranial-to-caudal direction. As it elongates caudally, the pronephric duct induces nearby intermediate mesoderm in the thoracolumbar area to become epithelial tubules called mesonephric tubules. Each mesonephric tubule receives a blood supply from a branch of the aorta, ending in a capillary tuft analogous to the glomerulus of the definitive nephron. The mesonephric tubule forms a capsule around the capillary tuft, allowing for filtration of blood.
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Sometimes these patients are described as having a 'Chiari [type] 0'. There are many suspected causes of tonsillar herniation including: decreased or malformed posterior fossa (the lower, back part of the skull) not providing enough room for the cerebellum; hydrocephalus or abnormal CSF volume pushing the tonsils out; or dural tension pulling the brain caudally. Connective tissue disorders, such as Ehlers Danlos syndrome, can be associated. For further evaluation of tonsillar herniation, CINE flow studies are used.
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Laterally, the septum verum reaches the lower part of the lateral ventricles, with the septal nuclei forming a bulge into the medial side of the ventricles. Dorsally can be found the septum pellucidum, a thin membrane of glial cells and fibres that separate the ventricles, and anteriorly is the lamina terminalis. It continues caudally as the pre-optic area and hypothalamus. The subfornical organ (SFO) can also be found in this area, between the ventral side of the fornix and the interventricular foramina.
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Cytoarchitectonically it is bounded caudally by the triangular area 45, medially by the prefrontal area 11 of Brodmann-1909, and rostrally by the frontopolar area 10 (Brodmann-1909). It incorporates the region that Brodmann identified as "Area 12" in the monkey, and therefore, following the suggestion of Michael Petrides, some contemporary neuroscientists refer to the region as "BA47/12". BA47 has been implicated in the processing of syntax in oral and sign languages, musical syntax, and semantic aspects of language.
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The supramarginal gyrus is located just anterior to the angular gyrus allowing these two structures (which compose the inferior parietal lobule) to form a multimodal complex that receives somatosensory, visual, and auditory inputs from the brain. Although the supramarginal gyrus is not considered a major portion of the language circuit, it still works with the angular gyrus to attempt to link words with meanings. It is also bound caudally by the lateral sulcus, one of the most prominent structures found in the brain.
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Each kidney is about long, wide, and divided into a cranial, middle, and caudal sections by large veins. The caudal section is the largest, extends into the middle of the pelvis. The ureters leave the ventral caudomedial surface and continue caudally, near the midline into the opening of the urodeum of the cloaca. Although there is no bladder, a dilated pouch of ureter stores the urine until it is secreted continuously down from the ureters to the urodeum until discharged.
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Skates are cartilaginous fishes like other Chondrichthyes, however, skates, like rays and other Rajiformes, have a flat body shape with flat pectoral fins that extend the length of their body. A large portion of the skate's dorsal body is covered by rough skin made of placoid scales. Placoid scales have a pointed tip that is oriented caudally and are homologous to teeth. Their mouths are located on the underside of the body, with a jaw suspension common to Batoids known as euhyostyly.
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During early development (approximately day 22 in humans), the pronephric duct forms from the intermediate mesoderm, ventral to the anterior somites. The cells of the pronephric duct migrate caudally whilst inducing adjacent mesenchyme to form the tubules of the initial kidney-like structure called the pronephros. This process is regulated by Pax2/8 markers. The pronephros is active in adult forms of some primitive fish and acts as the primary excretory system in amphibious larvae and embryonic forms of more advanced fish.
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The structure contains a high proportion of multisensory neurons and plays a role in the motor control of orientation behaviours of the eyes, ears and head. Receptive fields from somatosensory, visual and auditory modalities converge in the deeper layers to form a two-dimensional multisensory map of the external world. Here, objects straight ahead are represented caudally and objects on the periphery are represented rosterally. Similarly, locations in superior sensory space are represented medially, and inferior locations are represented laterally.
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In the human this area is known as ventral anterior cingulate area 24, and it refers to a subdivision of the cytoarchitecturally defined cingulate cortex region of cerebral cortex (area cingularis anterior ventralis). It occupies most of the anterior cingulate gyrus in an arc around the genu of the corpus callosum. Its outer border corresponds approximately to the cingulate sulcus. Cytoarchitecturally it is bounded internally by the pregenual area 33, externally by the dorsal anterior cingulate area 32, and caudally by the ventral posterior cingulate area 23 and the dorsal posterior cingulate area 31.
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Brodmann area 46 roughly corresponds with the dorsolateral prefrontal cortex (DLPFC), although the borders of area 46 are based on cytoarchitecture rather than function. The DLPFC also encompasses part of granular frontal area 9, directly adjacent on the dorsal surface of the cortex. Cytoarchitecturally, BA46 is bounded dorsally by the granular frontal area 9, rostroventrally by the frontopolar area 10 and caudally by the triangular area 45 (Brodmann-1909). There is some discrepancy between the extent of BA8 (Brodmann-1905) and the same area as described by Walker (1940).
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Brodmann area 45 (BA45), is part of the frontal cortex in the human brain. It is situated on the lateral surface, inferior to BA9 and adjacent to BA46. This area in humans occupies the triangular part of inferior frontal gyrus (H) and, surrounding the anterior horizontal limb of the lateral sulcus (H), a portion of the orbital part of the inferior frontal gyrus (H). Bounded caudally by the anterior ascending limb of the lateral sulcus (H), it borders on the insula in the depth of the lateral sulcus.
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It is a subdivision of the cytoarchitecturally defined precentral region of cerebral cortex. In the human brain, it is located on the portions of the precentral gyrus that are not occupied by Brodmann area 4; furthermore, BA6 extends onto the caudal portions of the superior frontal and middle frontal gyri. It extends from the cingulate sulcus on the medial aspect of the hemisphere to the lateral sulcus on the lateral aspect. It is bounded rostrally by the granular frontal region and caudally by the gigantopyramidal area 4 (Brodmann, 1909).
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In the human subcentral area 43, a sub area of the cytoarchitecture is defined in the postcentral region of the cerebral cortex. It occupies the postcentral gyrus, which is between the ventrolateral extreme of the central sulcus and the depth of the lateral sulcus, at the insula. Its rostral and caudal borders are approximated by the anterior subcentral sulcus and the posterior subcentral sulcus, respectively. Cytoarchitecturally, it is bounded rostrally, by the agranular frontal area 6, and caudally, for the most part, by the caudal postcentral area 2 and the supramarginal area 40.
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Also, the brain is relatively larger and fills more of the cranial cavity in juveniles compared to adults. The mouth is initially terminal, but shifts back as the fish grows. The dorsal fin typically reaches to the back of the head in young juveniles, and gradually moves caudally until it only extends to the mid-dorsal region in adults. They show a gradual change in body form as they develop, but no metamorphosis is externally detectable and no obvious point occurs at which they can be termed adult.
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There are two main methods of upper forelimb flexion. The first method involves pulling the limb forward, so that the elbow flexes and the shoulder extends. This method tends to place more strain on the structures of the caudal elbow and cranial shoulder, and is best at localizing lameness to the bicipital bursa or the supraglenoid tubercle of the scapula, but also places strain on the biceps and triceps muscles and tendons, and the olecranon. The alternative method involves pulling the limb caudally, which flexes the shoulder and extends the elbow.
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Cribbing, or crib biting, involves a horse grasping a solid object such as the stall door or fence rail with its incisor teeth, arching its neck, and contracting the lower neck muscles to retract the larynx caudally. This movement is coincided with an in-rush of air through the crico- pharynx into the oesophagus producing the characteristic cribbing sound or grunt. Usually, air is not swallowed but returns to the pharynx. It is considered to be an abnormal, compulsive behavior or stereotypy, and often labelled as a stable vice.
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Cytoarchitecturally it is bounded caudally by the inferior temporal area 20, the middle temporal area 21, the superior temporal area 22 and the ectorhinal area 36 (Brodmann-1909). Cytoarchitectonic and chemoarchitectonic studies find that it contains at least seven subareas, one of which, "TG", is unique to humans. The temporal pole is a paralimbic region involved in high level semantic representation and socio-emotional processing. The uncinate fasciculus provides a direct bidirectional path to the orbitofrontal cortex, allowing mnemonic representations stored in the temporal pole to bias decision making in the frontal lobe.
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The orbital part of inferior frontal gyrus also known as the pars orbitalis is the orbital part of the inferior frontal gyrus. In humans, this region is bordered by the triangular part of the inferior frontal gyrus (pars triangularis) and, surrounding the anterior horizontal limb of the lateral sulcus, a portion of the opercular part of inferior frontal gyrus (pars opercularis). Bounded caudally by the anterior ascending limb of the lateral sulcus, it borders on the insula in the depth of the lateral sulcus. It is bordered anteriorly/inferiorly by the lateral orbital sulcus.
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The embryonic disc begins flat and round, but eventually elongates to have a wider cephalic part and narrow-shaped caudal end. At the beginning, the primitive line extends in cephalic direction and 18 days after fertilization returns caudally until it disappears. In the cephalic portion, the germ layer shows specific differentiation at the beginning of the 4th week, while in the caudal portion it occurs at the end of the 4th week. Cranial and caudal neuropores become progressively smaller until they close completely (by day 26) forming the neural tube.
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Howard (1957), Hopson (1964), Brodkorb (1967: p. 142), Wetmore (1917), Bourdon (2005), Mayr (2008, 2009), Mayr et al. (2008), TZ [2009] While the authors claim it is beyond the paper's scope, the study describing Protodontopteryx suggests that the proposed pro-galloansere traits might actually be plesiomorphic in relation to Aves. It also notes "striking" similarities between pelagornithids and Ichthyornis in terms of jaw anatomy, but still classifies them as neognaths due to the well-developed hypotarsal crests, a supratendineal bridge on the distal tibiotarsus and the caudally closed ilioischiadic foramen.
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Traumatic subarachnoid pneumorrhachis is almost always secondary to major trauma and is a marker of a severe injury. The pathophysiology described for it states that the penetrated air, which had led to the formation of pneumocephalus might have been forced caudally due to the raised intracranial pressure as a consequence of severe brain injury and patient's horizontal position allowing the entrapped air to pass through the foramen magnum into the spinal canal. Due to its rareness, asymptomatic presentation and myriad etiologies, no guidelines for its treatment or care has been described. Pneumorrhachis typically resolves spontaneously but occasionally it can have serious complications.
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Brodmann area 40 (BA40) is part of the parietal cortex in the human brain. The inferior part of BA40 is in the area of the supramarginal gyrus, which lies at the posterior end of the lateral fissure, in the inferior lateral part of the parietal lobe. It is bounded approximately by the intraparietal sulcus, the inferior postcentral sulcus, the posterior subcentral sulcus and the lateral sulcus. It is bounded caudally by the angular area 39 (H), rostrally and dorsally by the caudal postcentral area 2, and ventrally by the subcentral area 43 and the superior temporal area 22 (Brodmann-1909).
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Brodmann areas 3, 1, and 2 make up the primary somatosensory cortex of the human brain (or S1). Because Brodmann sliced the brain somewhat obliquely, he encountered area 1 first; however, from anterior to posterior, the Brodmann designations are 3, 1, and 2, respectively. Brodmann area (BA) 3 is subdivided into areas 3a and 3b. Where BA 1 occupies the apex of the postcentral gyrus, the rostral border of BA 3a is in the nadir of the Central sulcus, and is caudally followed by BA 3b, then BA 1, with BA 2 following and ending in the nadir of the postcentral sulcus.
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The telencephalon gradually expands laterally to a much greater extent than it does dorsally or ventrally, and its connection to the remainder of the neural tube reduces to the interventricula foramina. The diencephalon expands more evenly, but caudally of the diencephalon the canal remains narrow. The third ventricle is the space formed by the expanding canal of the diencephalon. The hypothalamic region of the ventricle develops from the ventral portion of the neural tube, while the thalamic region develops from the dorsal portion; the wall of the tube thickens and becomes the hypothalamus and thalamus respectively.
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The evolutionary diversifications and specialization in functions of the dorsal pallium have been more difficult to decipher. It is widely believed to be the progenitor of the bulk of the mammalian cerebral cortex, although the evidence for this is considered by some anatomists not yet to be conclusive. Importantly, the lateral and ventral parts of the pallium produce also deep to their respective sectors of subpial olfactory cortex sets of pallial nuclei, the neurons entering the claustrum, rostrally, and the pallial amygdala, caudally. The concept of hypopallium refers to this histogenetically unitary complex of olfactory (piriform) cortex and deep pallial nuclei.
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The main function of the SCO is the secretion of the glycoprotein SCO-spondin, which is released into the third ventricle where it aggregates to create Reissner's fiber (RF). Reissner's fiber is a long fibrous projection that travels caudally through the Sylvian aqueduct and terminates in the spinal cord. This fiber is thought to contribute to the maintenance of the patency of the sylvian aqueduct. While the function of the subcommissural organ is still under investigation, it has been hypothesized that it is also part of the mechanism of aldosterone secretion and CSF detoxification, along with osmoregulation.
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This stylised bird skeleton highlights the uncinate processes The uncinate processes of the ribs are extensions of bone that project caudally from the vertical segment of each rib. (Uncinate means hooked from Latin uncinatus, from uncinus, barb, from uncus, hook.) They are found in birds (except for screamers), reptiles, and the early amphibian Ichthyostega. These processes can serve to attach scapula muscles, and help to strengthen the rib cage overlapping with the rib behind them. They are also shown to have a role in respiration by increasing the effectiveness of muscles involved in inspiration including the appendicocostal muscles.
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Axial section of the Brainstem (Pons) at the level of the Facial Colliculus The abducens nucleus is located in the pons, on the floor of the fourth ventricle, at the level of the facial colliculus. Axons from the facial nerve loop around the abducens nucleus, creating a slight bulge (the facial colliculus) that is visible on the dorsal surface of the floor of the fourth ventricle. The abducens nucleus is close to the midline, like the other motor nuclei that control eye movements (the oculomotor and trochlear nuclei). Motor axons leaving the abducens nucleus run ventrally and caudally through the pons.
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As in the brainstem, higher segments of the spinal cord contain α-MNs that innervate muscles higher on the body. For example, the biceps brachii muscle, a muscle of the arm, is innervated by α-MNs in spinal cord segments C5, C6, and C7, which are found rostrally in the spinal cord. On the other hand, the gastrocnemius muscle, one of the muscles of the leg, is innervated by α-MNs within segments S1 and S2, which are found caudally in the spinal cord. Alpha motor neurons are located in a specific region of the spinal cord's gray matter.
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The medial reticular formation and lateral reticular formation are two columns of nuclei with ill-defined boundaries that send projections through the medulla and into the midbrain. The nuclei can be differentiated by function, cell type, and projections of efferent or afferent nerves. Moving caudally from the rostral midbrain, at the site of the rostral pons and the midbrain, the medial RF becomes less prominent, and the lateral RF becomes more prominent. Existing on the sides of the medial reticular formation is its lateral cousin, which is particularly pronounced in the rostral medulla and caudal pons.
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It occupies the medial part of the base of the posterior grey column and appears on the transverse section as a well-defined oval area. It begins caudally at the level of the second or third lumbar nerve, and reaches its maximum size opposite the twelfth thoracic nerve. Above the level of the eight thoracic nerve its size diminishes, and the column ends opposite the last cervical or first thoracic nerve. It is represented, however, in the other regions by scattered cells, which become aggregated to form a cervical nucleus opposite the third cervical nerve, and a sacral nucleus in the middle and lower part of the sacral region.
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Granular insular cortex (or visceral area) refers to a portion of the cerebral cortex defined on the basis of internal structure in the human and macaque, the rat, and the mouse. Classified as neocortex, it is in primates distinguished from adjacent allocortex (periallocortex) by the presence of granular layers – external granular layer (II) and internal granular layer (IV) – and by differentiation of the external pyramidal layer (III) into sublayers. In primates it occupies the posterior part of the insula. In rodents it is located on the lateral surface of the cortex rostrally, dorsal to the gustatory area or, more caudally, dorsal to the agranular insula.
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However, better preparation of the holotype specimen MGB 512, a nearly complete articulated skeleton embedded in a limestone matrix now housed in the Museu de Ciències Naturals de Barcelona, allowed for a revision of the species in 1990 in which the name Montsecosuchus was first used. Holotipe of Montsecosuchus genus Montsecosuchus differs in several ways from other atoposaurids such as Alligatorium, Alligatorellus, and Theriosuchus. Several characteristics of the skull including the presence of an ungrooved parietal- squamosal suture and a caudally projecting retroarticular process distinguish Montsecosuchus from these genera. Both Montsecosuchus and Alligatorellus possess three sacral vertebrae; this may be a shared synapomorphy of the two genera.
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A Type I Chiari malformation is a congenital anomaly of the brain in which the cerebellar tonsils are elongated and pushed down through the opening of the base of the skull (see foramen magnum), blocking the flow of cerebrospinal fluid (CSF) as it exits through the medial and lateral apertures of the fourth ventricle. Also called cerebellar tonsillar ectopia, or tonsillar herniation. Although often congenital, Chiari malformation symptoms can also be induced due to physical head trauma, commonly from raised intracranial pressure secondary to a hematoma, or increased dural strain pulling the brain caudally into the foramen magnum. Head trauma increases risk of cerebellar tonsillar ectopia by a factor of 4.
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Although the spinal cord cell bodies end around the L1/L2 vertebral level, the spinal nerves for each segment exit at the level of the corresponding vertebra. For the nerves of the lower spinal cord, this means that they exit the vertebral column much lower (more caudally) than their roots. As these nerves travel from their respective roots to their point of exit from the vertebral column, the nerves of the lower spinal segments form a bundle called the cauda equina. There are two regions where the spinal cord enlarges: Cervical enlargement - corresponds roughly to the brachial plexus nerves, which innervate the upper limb.
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It has been suggested that caudal luring was involved in the evolution of the tail vibration rattle of rattlesnakes, a warning signal and a way of auditory communication, though this has been challenged. Prey luring, in general, is confounded by false interpretation, as the wiggling of an appendage could have other behavioral meanings including aposematism, defence, or nervous release, and experimental evidence has been weak. Caudal luring is thought to have evolved from a caudally localized intention movement (a behavior derived from locomotor movements). Essentially, the act of remaining stationary while sensing prey produces general nervous system excitation that gets released in the form of tail movements.
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Area 11 is a subdivision of the cytoarchitecturally defined frontal region of cerebral cortex of the human. As illustrated in Brodmann-10, It constitutes most of the orbital gyri, gyrus rectus and the most rostral portion of the superior frontal gyrus. It is bounded medially by the inferior rostral sulcus (H) and laterally approximately by the frontomarginal sulcus (H). Cytoarchitecturally it is bounded on the rostral and lateral aspects of the hemisphere by the frontopolar area 10, the orbital area 47, and the triangular area 45; on the medial surface it is bounded dorsally by the rostral area 12 and caudally by the subgenual area 25.
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The development of the pronephric duct is a part of the development of the urinary system, and the development of the reproductive system. In the outer part of the intermediate mesoderm, immediately under the ectoderm, in the region from the fifth cervical segment to the third thoracic segment, a series of short evaginations from each segment grows dorsally and extends caudally, fusing successively from before backward to form the pronephric duct. This continues to grow caudalward until it opens into the ventral part of the cloaca; beyond the pronephros it is termed the mesonephric duct. Thus, the mesonephric duct remains after the atrophy of the pronephros.
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The verumontanum is an important anatomic landmark for pathology in a congenital anomaly known as posterior urethral valves, in which there is a developmental obstruction of the urethra in newborn male infants. Urethral carcinoid tumors have been reported at the verumontanum.Maxwell Smith, M Scott Lucia, Priya N Werahera and Francisco G La Rosa Carcinoid tumor of the verumontanum (colliculus seminalis) of the prostatic urethra with a coexisting prostatic adenocarcinoma: a case report Journal of Medical Case Reports 2010, 4:16 The structure tends to migrate caudally, or downward, in hypospadia disorders and is then seen in the bulbous, or penile portion of the urethra.F Ikoma, H Shima. 1991.
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In the superior region of the pons is the locus coeruleus, which due to its concentration of noradrenaline has a sky blue appearance, visible (in a colour closer to teal) through the floor of the ventricle, superiorly to the superior fovea. The internal part of the facial nerve bulges into the ventricle, forming the facial colliculus, in the process of looping around the abducens nucleus within the inferior region of the Pons. The medulla oblongata is located behind the inferior portion of the floor (and continues caudally of the ventricle). Medullary striae emerge via the median sulcus and run transversely across the floor to become part of the inferior cerebellar peduncle.
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The rostral neuropore or anterior neuropore is a region corresponding to the opening of the embryonic neural tube in the anterior portion of the developing prosencephalon. The central nervous system develops from the neural tube, which initially starts as a plate of cells in the ectoderm and this is called the neural plate, the neural plate then undergoes folding and starts closing from the center of the developing fetus, this leads to two open ends, one situated cranially/rostrally and the other caudally. Bending of the neural plate begins on day 22,Human Embryology, 4th edition, PA and the cranial neuropore closes on day 24.O'Rahilly R, Müller F. Bidirectional closure of the rostral neuropore in the human embryo].
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Sometimes called the olfactory cortex, olfactory lobe or paleopallium, piriform cortical regions are present in the brains of amphibians, reptiles and mammals. The piriform cortex is among three areas that emerge in the telencephalon of amphibians, situated caudally to a dorsal area, which is caudal to a hippocampal area. Further along the phylogenic timeline, the telencephalic bulb of reptiles as viewed in a cross section of the transverse plane extends with the archipallial hippocampus folding toward the midline and down as the dorsal area begins to form a recognizable cortex. As mammalian brains developed, volume of the dorsal cortex increased in slightly greater proportion, as compared proportionally with increased overall brain volume, until it enveloped the hippocampal regions.
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1996, pp. 522-525. which has a role in analgesia, quiescence, and bonding. The dorsal raphe nucleus (which releases serotonin in response to certain neural activity) is located at the ventral side of the periaqueductal grey, at the level of the inferior colliculus. The nuclei of two pairs of cranial nerves are similarly located at the ventral side of the periaqueductal grey – the pair of oculomotor nuclei (which control the eyelid, and most eye movements) is located at the level of the superior colliculus, while the pair of trochlear nuclei (which helps focus vision on more proximal objects) is located caudally to that, at the level of the inferior colliculus, immediatetly lateral to the dorsal raphe nucleus.
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The olfactory system is made up in part of the RMS which stretches from the subventricular zone in the wall of the lateral ventricle, through the basal forebrain, to the olfactory bulb (OB). VONS is the name given to this pathway, and it consists of the subventricular zone, the RMS, the olfactory tract and the olfactory bulb. Developing neurons leave the subventricular zone and enter the RMS and travel caudally and ventrally along the undersurface of the caudate nucleus; this is referred to as the descending limb. Upon reaching the ventral side of the caudate nucleus, the neurons follow the rostral limb and travel ventrally and rostrally, entering the anterior olfactory cortex (AOC).
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The mammary ridge is primordial for the mammary gland on the breast in humans, and is associated with mammary gland and breast development. In human embryogenesis the mammary ridge usually appears as a narrow, microscopic ectodermal thickening during the first seven weeks of pregnancy and grows caudally as a narrow, linear ridge. In many mammals, these glands first appear as elevated ridges along the milk lines, which then separate into individual buds located in regions lateral to the ventral midline. The location of these buds varies according to species: they are located in the thoracic region in primates, in the inguinal area in ungulates, and along the entire length of the trunk in rodents and pigs.
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In birds, the primitive streak formation is generated by a thickening of the epiblast called the Koller's sickle The Koller's sickle is created at the posterior edge of the area pellucida while the rest of the cells of the area pellucida remain at the surface, forming the epiblast. In chicks, the mesoderm cells don't invaginate like in amphibians, but they migrate medially and caudally from both sides and create a midline thickening called primitive streak. Which grows rapidly in length as more and more presumptive mesoderm cells continue to aggregate inward. Gastrulation begins in the area pellucida next to the posterior marginal zone, as the hypoblast and primitive streak both start there.
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Prior to pervasive use and availability of advanced methods of neuroimaging, it is possible that the rate of incidence of congenital dermal sinus has been supplemented by the incidence of coccygeal pits. Coccygeal pits are distinct from congenital dermal sinus as they are found within the gluteal cleft, rather than above the gluteal cleft. The caudally orientated coccygeal pits are not associated with intradural pathology and do not need to be excised, unlike the cephalically oriented tracts of the congenital dermal sinus which confer great intradural pathology and require surgical intervention. While coccygeal pits occur in 4% of neonate population, congenital dermal sinus is only found in 1 in 2500 live births.
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After removing these soft tissue attachments to the pelvis, dissection is continued dorsally (on top of the penis) to remove the dorsal retractor penile muscle and other soft tissue covering the site of the required urethral incision. All of these dissection steps are necessary to free the penis from the pelvis, allowing the veterinarian to move the significantly wider pelvic urethra caudally (or rearward) so it can be attached to the skin. After the penile body is freed, a dorsal incision is started at the tip of the penis using either a small scalpel blade or fine ophthalmic scissors. This incision is extended to a level at or above the bulbourethral glands.
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A diagnosis is a statement of the anatomical features of an organism (or group) that collectively distinguish it from all other organisms. Some, but not all, of the features in a diagnosis are also autapomorphies. An autapomorphy is a distinctive anatomical feature that is unique to a given organism or group. According to Ezcurra (2007), and Bristowe and Raath (2004) Coelophysis can be distinguished based on the following features: the absence of an offset rostral process of the maxilla; the quadrate is strongly caudally; a small external mandibular fenestra, which is 9–10% of the mandibular length; and the anteroposterior length of the ventral lacrimal process is greater than 30% of its height.
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The mammillotegmental fasciculus (or mammillotegmental tract, mammillo- tegmental bundle of Gudden, or Fasciculus mammillotegmentalis) is a small bundle of efferent fibers from the hypothalamus running from the mammillary body to the tegmentum. Its functions are not well defined for humans, but based on animal studies it seems to be related to regulating visceral function and processing spatial information. The mammillotegmental fasciculus was first described by the German neuroanatomist, Bernhard von Gudden, from which it takes its alternate name, mammillo-tegmental bundle of Gudden. The mammillotegmental fasciculus emerges from the principal mammillary fasciculus of the mammillary body and travels dorsally together with the mammillothalamic tract before splitting off and turning caudally to enter the spinal column.
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The starry flounder has a multitude of well studied behaviors that are exhibited on a daily basis. At a normal resting position the dorsal and anal fins are angled so to prevent the body from resting upon the substrate, support being given by the fins, so as to create a cushion of water between the fish and the substrate. This is also for water to escape through an opening on the blind side, gill slit, of the fish and lessens the amount of effort needed to move. Movement of this fish has been described to look much like crawling, with the first few rays of the dorsal and anal fins moving in a rowing motion that progresses caudally along the fish creating a waving movement of the fins, propelling the fish forward.
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The telencephalic part of the rostral choroidal tela (roof plate continuous caudally with a diencephalic part) is inserted at the back of this commissure at a locus where mammals show the subfornical circumventricular organ, and extends laterally over the interventricular foramen into a wing-shaped medial telencephalic territory, the so-called choroidal fissure. Here the choroidal tissue is attached to the fimbria of the hippocampus (also known as the cortical hem area), bordering lengthwise the medial pallium. At its rostral and caudal ends, the medial pallium contacts the ventral pallium, which builds the pallial portion that contacts the subpallium across the pallio subpallial boundary, observed at the lateral telencephalic wall. Inside the ring formed thus by the medial and ventral pallium there is a sort of island that contains the dorsal and lateral pallial portions.
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With patient lying supine, the examination of the duodenum with high frequency ultrasound duodenography is performed with 7.5MHz probe placed in the right upper abdomen, and central epigastric successively; for high frequency ultrasound colonography, the ascending colon, is examined with starting point usually midway of an imaginary line running from the iliac crest to the umbilicus and proceeding cephalid through the right mid abdomen; for the descending colon, the examination begins from the left upper abdomen proceeding caudally and traversing the left mid abdomen and left lower abdomen, terminating at the sigmoid colon in the lower pelvic region. Color flow Doppler sonography is used to examine the localization of lesions in relation to vessels. All measurements of diameter and wall thickness are performed with built-in software. Measurements are taken between peristaltic waves.
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The actual blood flow caudally through these arteries, derived from the posterior cerebral circulation, is inadequate to maintain the spinal cord beyond the cervical segments. The major contribution to the arterial blood supply of the spinal cord below the cervical region comes from the radially arranged posterior and anterior radicular arteries, which run into the spinal cord alongside the dorsal and ventral nerve roots, but with one exception do not connect directly with any of the three longitudinal arteries. These intercostal and lumbar radicular arteries arise from the aorta, provide major anastomoses and supplement the blood flow to the spinal cord. In humans the largest of the anterior radicular arteries is known as the artery of Adamkiewicz, or anterior radicularis magna (ARM) artery, which usually arises between L1 and L2, but can arise anywhere from T9 to L5.
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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.
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The spinothalamic tract – another ribbon- like region of fibres – are located at the lateral edge of the tegmentum; at the level of the inferior colliculus it is immediately dorsal to the medial lemiscus, but due to the rostral widening of the tegmentum, is lateral of the medial lemiscus at the level of the superior colliculus. A prominent pair of round, reddish, regions – the red nuclei (which have a role in motor co- ordination) – are located in the rostral portion of the midbrain, somewhat medially, at the level of the superior colliculus. The rubrospinal tract emerges from the red nucleus and descends caudally, primarily heading to the cervical portion of the spine, to implement the red nuclei's decisions. The area between the red nuclei, on the ventral side – known as the ventral tegmental area – is the largest dopamine-producing area in the brain, and is heavily involved in the neural reward system.
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The development of the star-like appendages suggests precursors with proto-appendages on an ancestor's snout, which became elevated over successive generations. Although this theory lacks fossil evidence or supporting comparative data, nearly all extant moles have sheets of the Eimer’s organ making up the epidermis of their snout around the nares. Also, recent studies of Catania and colleagues identified one North American species (Scapanus townsendii) with a set of proto-appendages extending caudally on the snout which exhibit a striking resemblance to the embryonic stages of the star-nosed mole, although Scapanus townsendii has only eight subdivisions on its face, rather than the 22 appendages found on the star-nosed mole. Such change is of common occurrence in evolution and is explained by the advantage of efficiently adding modules to the body plan without need to reinvent the regulatory elements which produce each module.
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Reissner’s fiber (RF) is a complex and dynamic structure present in the third and fourth ventricles and in the central canal of the spinal cord, observed in almost all vertebrates. It is formed by the assembly of complex and variable high weight molecular glycoproteins secreted by the SCO that are released to the cerebrospinal fluid. At least five different proteins were found, of 630 kDa, 480 kDa, 390 kDa, 320 kDa and, the major constituent, 200kDa that is present in both RF and cerebrospinal fluid, CSF. One of the most important RF-glycoproteins secreted by the SCO has been named SCO-spondin and is of major importance especially during embryonic life. Reissner’s fiber grows caudally by the addition of those glycoproteins at its cephalic end and extends along the brain aqueduct (Aqueduct of Sylvius), and the entire length of the central canal of the spinal cord, growing continuously in the caudal direction.
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The only axon of the Mauthner cell reaches from the cell to the midline of the hindbrain, promptly crosses it to the contralateral side, and then descends caudally along the spinal cord. A single discharge of the M-cell achieves a whole set of parallel effects onto the spinal motor networks: 1) it monosynaptically excites large primary motoneurons at one side of the body; 2) disinaptically excites smaller motoneurons at the same side of the body; 3) initiates action potentials in inhibitory interneurons electrically coupled to the M-cell axon, and by their means inhibits a) inhibitory interneurons still at the same side of the body (to prevent them from interfering with the C-start), as well as b) motoneurons at the other side of the body. As a result of this pattern of activation the quick muscles at one side of the body contract simultaneously, while the muscles at the other side of the body relax.
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The triple tibial osteotomy was developed by a New Zealand veterinary orthopaedic specialist, Dr. Warrick Bruce, while he was working in Adelaide, South Australia. By changing the geometry of the forces of gravity and muscle contractions that act on the stifle during weight-bearing, it aims to neutralise the shear force that causes the cranial movement of the tibia with respect to the femur. This shear force develops because the canine tibial plateau – the weight-bearing aspect of the joint – is sloped caudally (downwards towards the back of the joint) and there is an acute angle between the tibial plateau slope and the patellar ligament. In the triple tibial osteotomy procedure, the tibia has three osteotomies (cuts into the bone with a bone saw) performed upon it with the aim of realigning the tibial plateau slope so that it ultimately becomes aligned at right angles to the patellar ligament instead of sloping backwards.
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Fourth ventricle location shown in red (E), pons (B); the floor of the ventricle is to the right, the roof to the left The fourth ventricle has a roof at its upper (posterior) surface and a floor at its lower (anterior) surface, and side walls formed by the cerebellar peduncles (nerve bundles joining the structure on the posterior side of the ventricle to the structures on the anterior side). The caudal tip of the fourth ventricle - where it becomes the central canal - is known as the obex; the obex is also a marker for the level of the foramen magnum of the skull and therefore is a marker for the imaginary dividing line between the medulla and spinal cord The superior portion of the roof (i.e. of the posterior edge) is a thin lamina - the superior medullary velum - connecting the left and right superior cerebellar peduncles together. The inferior portion of the roof - the inferior medullary velum - has a tricorn cross section, directed caudally and laterally, and is formed by the Cerebellum directly.
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