Contemplate the ideal smile as recounted by one clinician in the Journal of Clinical Orthodontics: An optimal smile is characterized by an upper lip that reaches the gingival margins, with an upward or straight curvature between the philtrum and commissures; an upper incisal line coincident with the border of the lower lip; minimal or no lateral negative space; a commissural line and occlusal frontal plane parallel to the pupillary line; and harmoniously integrated dental and gingival components.
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Torsion created a condition in the cerebrovisceral commissures called streptoneury. Secondarily, some gastropod lineages detorted: they reversed the torsion event and straightened out their internal organs, uncrossing the commissures in the process. It is this second state, one in which the commissures have once again become untwisted, that is called euthyneury. The Opisthobranchia represent one of the more prominent gastropod lineages that have undergone euthyneury.
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Gastropods that were placed in this taxon have bifurcate tentacle nerves and two pedal commissures.
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Commissural tracts connect corresponding cortical areas in the two hemispheres. They cross from one cerebral hemisphere to the other through bridges called commissures. The great majority of commissural tracts pass through the largest commissure the corpus callosum. A few tracts pass through the much smaller anterior and posterior commissures.
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Hilar mossy cells and CA3 Pyramidal cells are the main origins of hippocampal commissural fibers. They pass through hippocampal commissures to reach contralateral regions of hippocampus. Hippocampal commissures have dorsal and ventral segments. Dorsal commissural fibers consists mainly of entorhinal and presubicular fibers to or from the hippocampus and dentate gyrus.
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When this gene is mutated or any of its interactions are altered phenotypes such as fused commissures can be seen as a result of improper segregation.
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Commissural tracts enable the left and right sides of the cerebrum to communicate with each other. Other commissures are the hippocampal commissure, and the habenular commissure.
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Smaller commissures, including the anterior commissure, the posterior commissure and the fornix, also join the hemispheres and these are also present in other vertebrates. These commissures transfer information between the two hemispheres to coordinate localized functions. There are three known poles of the cerebral hemispheres: the occipital pole, the frontal pole, and the temporal pole. The central sulcus is a prominent fissure which separates the parietal lobe from the frontal lobe and the primary motor cortex from the primary somatosensory cortex.
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In tests, memory in either hemisphere of split-brained patients is generally lower than normal, though better than in patients with amnesia, suggesting that the forebrain commissures are important for the formation of some kinds of memory. This suggests that posterior callosal sections that include the hippocampal commissures cause a mild memory deficit (in standardised free- field testing) involving recognition.Tramo MJ, Baynes K, Fendrich R, Mangun GR, Phelps EA, Reuter- Lorenz PA, Gazzaniga MS (1995): Hemispheric specialization and interhemispheric integration: Insights from experiments with commissurotomy patients. In: Epilepsy and the Corpus Callosum 2.
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The stigmas are decurrent along the commissures of the ovary and sometimes extended above, to form false styles called stylodia. The stigmatic areas are dry. The megagametophyte is of the Polygonum type. The fruit is an erect, membranous capsule, which opens at the apex only.
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Disruption of the circular nature of this muscle can have a significant effect on oral function. In addition, there are other muscles both above and below the lips that attach either to the orbicularis oris or to the fibrous bands extending from the commissures.
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In the corner lift procedure (external angle oral commissuroplasty), triangles of tissue are resected from above the commissures, thereby elevating the corners of the mouth. A descending wedge of tissue can also be removed to add contour to the Cupid's bow or to reduce bulky lips.
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Canthus (pl. canthi, palpebral commissures) is either corner of the eye where the upper and lower eyelids meet. More specifically, the inner and outer canthi are, respectively, the medial and lateral ends/angles of the palpebral fissure. The bicanthal plane is the transversal plane linking both canthi and defines the upper boundary of the midface.
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The "brain" of adult articulates consists of two ganglia, one above and the other below the oesophagus. Adult inarticulates have only the lower ganglion. From the ganglia and the commissures where they join, nerves run to the lophophore, the mantle lobes and the muscles that operate the valves. The edge of the mantle has probably the greatest concentration of sensors.
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It is caused by an autoimmune reaction to Group A β-hemolytic streptococci (GAS) that results in valvular damage. Fibrosis and scarring of valve leaflets, commissures and cusps leads to abnormalities that can result in valve stenosis or regurgitation. The inflammation caused by rheumatic fever, usually during childhood, is referred to as rheumatic valvulitis. About half of patients with rheumatic fever develop inflammation involving valvular endothelium.
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The superior part of the posterior border constitutes the habenular commissure, while more centrally it the pineal gland, which regulates sleep and reacts to light levels. Caudal of the pineal gland is the posterior commissure; nerve fibres reach the posterior commissure from the adjacent midbrain, but their onward connection is currently uncertain. The commissures create concavity to the shape of the posterior ventricle border, causing the suprapineal recess above the habenular, and the deeper pineal recess between the habenular and posterior commissures; the recesses being so-named due to the pineal recess being bordered by the pineal gland. The hypothalmic portion of the third ventricle (upper right), and surrounding structures The anterior wall of the ventricle forms the lamina terminalis, within which the vascular organ monitors and regulates the osmotic concentration of the blood; the cerebrum lies beyond the lamina, and causes it to have a slightly concave shape.
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Preganglionic nerve cells in the sympathetic nervous system (all of which come from the lateral grey column), use the neurotransmitter acetylcholine, while postganglionic sympathetic nerve cells use norepinephrine. Grey matter in the brain and spinal cord is any accumulation of cell bodies and neuropil (neuropil is tissue rich in nerve cell bodies and dendrites). White matter consists of nerve tracts (groups of axons) and commissures (tracts that cross the brain's midline).
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AC almost always affects the lower lip and only rarely the upper lip, probably because the lower lip is more exposed to the sun. In the unusual cases reported where it affects the upper lip, this may be due to upper lip prominence. The commissures (corners of the mouth) are not usually involved. Affected individuals may experience symptoms such as a dry sensation and cracking of the lips.
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Upon CNS injury astrocytes will proliferate, causing gliosis, a form of neuronal scar tissue, lacking in functional neurons. The brain (cerebrum as well as midbrain and hindbrain) consists of a cortex, composed of neuron- bodies constituting gray matter, while internally there is more white matter that form tracts and commissures. Apart from cortical gray matter there is also subcortical gray matter making up a large number of different nuclei.
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113–114 These muscles, collectively, are the meat for which prawns are commercially fished and farmed.Kanduri & Eckhardt, 2002, p. 42 The nervous system of prawns comprises a dorsal brain, and a ventral nerve cord, connected by two commissures around the oesophagus.Tavares & Martin, 2010, p. 114 The chief sensory inputs are visual input from the eyes, chemoreceptors on the antennae and in the mouth, and mechanoreceptors on the antennae and elsewhere.
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Callosal disconnection syndrome is characterized by left ideomotor apraxia and left-hand agraphia and/or tactile anomia, and is relatively rare. Other examples include commissurotomy, the surgical cutting of cerebral commissures to treat epilepsy and callosal agenesis which is when individuals are born without a corpus callosum. Those with callosal agenesis can still perform interhemispheric comparisons of visual and tactile information but with deficits in processing complex information when performing the respective tasks.
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Despite the presence of eyes, there appears to be no optic nerve. The pedal ganglia each send one nerve anteriorly and two posteriorly to control the foot. These ganglia are separated by a long, thin commissure and have one statocyst and statolith each, attached dorsally. It has one subintestinal ganglion, one visceral ganglion, one osphradial ganglion, two gastro- esophageal ganglia, one left parietal ganglion, and two buccal ganglia, along with the necessary commissures and connectives.
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Laryngeal cancers are mostly squamous cell carcinomas, reflecting their origin from the skin of the larynx. Cancer can develop in any part of the larynx, but the cure rate is affected by the location of the tumour. For the purposes of staging, the larynx is divided into three anatomical regions: the glottis (true vocal cords, anterior and posterior commissures); the supraglottis (epiglottis, arytenoids and aryepiglottic folds, and false cords); and the subglottis. Most laryngeal cancers originate in the glottis.
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Aspidogastreans have a nervous system of extraordinary complexity, greater than that of related free-living forms, and a great number of sensory receptors of many different types. The nervous system is of great complexity, consisting of a great number of longitudinal nerves (connectives) connected by circular commissures. The brain (cerebral commissure) is located dorsally, in the anterior part of the body, the eyes dorsally attached to it. A nerve from the main connective enters the pharynx and also supplies the intestine.
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Bundles of myelinated axons make up the nerve tracts in the CNS. Where these tracts cross the midline of the brain to connect opposite regions they are called commissures. The largest of these is the corpus callosum that connects the two cerebral hemispheres, and this has around 20 million axons. The structure of a neuron is seen to consist of two separate functional regions, or compartments – the cell body together with the dendrites as one region, and the axonal region as the other.
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Connecting each of the hemispheres is the corpus callosum as well as several additional commissures. One of the most important parts of the cerebral hemispheres is the cortex, made up of gray matter covering the surface of the brain. Functionally, the cerebral cortex is involved in planning and carrying out of everyday tasks. The hippocampus is involved in storage of memories, the amygdala plays a role in perception and communication of emotion, while the basal ganglia play a major role in the coordination of voluntary movement.
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The Talairach coordinate system is defined by making two anchors, the anterior commissure and posterior commissure, lie on a straight horizontal line. Since these two points lie on the midsagittal plane, the coordinate system is completely defined by requiring this plane to be vertical. Distances in Talairach coordinates are measured from the anterior commissure as the origin (as defined in the 1998 edition). The y-axis points posterior and anterior to the commissures, the left and right is the x-axis, and the z-axis is in the ventral-dorsal (down and up) directions.
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The mitral valve is a bileaflet valve sited between the left atrium and left ventricle, responsible for preventing blood flowing from the atrium to the ventricle when the heart contracts. It is elliptical, and its area varies from 5.0 to 11.4 cm2. The valve leaflets are separated by two commissures, and each leaflet of the valve (anterior leaflet, the large one, and posterior leaflet, the small one) has three sections (p1, p2, p3). Histologically, each leaflet is composed of the solid fibrosa, the spongiosa at the atrial surface and another fibroelastic layer covering the leaflets.
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A technical variant of the gull-wing lip lift is the sub-nasal lip lift (bull- horn lip lift), which involves the removal of either an ellipse or a curved- edge ellipse of tissue from under the nose. The skin then is raised, and sutured to lift the lip and expose more of the upper-lip vermilion.Greenwald AE. 1987. Depending upon the indications of the patient, this technique can increase the drooping the corners of the mouth (commissures); thus, the sub- nasal lip lift often includes a corner-lift surgical step.
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For example, nowadays a neurosurgical team that performs the procedure can use an MRI to identify the location of the anterior and posterior commissures. This approach allows neurosurgeons to obtain a number of coronal images, which are then used to calculate the stereotactic coordinates of the place in the anterior cingulate cortex, where lesions need to be created. Moreover, the MRI enables to differentiate more precisely the cell composition, and thus easily identify the gray matter in that region. This can then be further confirmed with the help of microelectrode recordings.
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Singer was born in Munich and studied medicine at the Ludwig Maximilian University of Munich (LMU Munich) from 1965 onwards (as a scholarship holder of the German Academic Scholarship Foundation) and 1965/66 two semesters at the Sorbonne in Paris. In 1968, he received his Ph.D. from Ludwig Maximilian University with his doctoral thesis on "The role of telencephalic commissures in bilateral EEG-synchrony." His doctoral supervisor was Otto Detlev Creutzfeldt of the Max Planck Institute for Psychiatry. During his advanced training in neurophysiology, he spent a year at the University of Sussex in England.
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Major gyri and sulci on the lateral surface of the cortex Lobes of the brain The cerebrum is the largest part of the brain, and is divided into nearly symmetrical left and right hemispheres by a deep groove, the longitudinal fissure. Asymmetry between the lobes is noted as a petalia. The hemispheres are connected by five commissures that span the longitudinal fissure, the largest of these is the corpus callosum. Each hemisphere is conventionally divided into four main lobes; the frontal lobe, parietal lobe, temporal lobe, and occipital lobe, named according to the skull bones that overlie them.
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It takes about one day for a stamen to complete its motions, and the order in which they do so varies from one flower to another. The area that is receptive to pollen, the stigmatic area, is not confined to the apex of the ovary or mounted on a style as in most flowers, but extends in bands down the sides of the ovary along the commissures, the seams where the carpels that compose the ovary are joined together. Such commissural stigmas have been discovered in Celastraceae,Merran L. Matthews and Peter K. Endress (2005). "Comparative floral structure and systematics in Celastrales".
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The central component of the nautilus nervous system is the oesophageal nerve ring which is a collection of ganglia, commissures, and connectives that together form a ring around the animal's oesophagus. From this ring extend all of the nerves forward to the mouth, tentacles, and funnel; laterally to the eyes and rhinophores; and posteriorly to the remaining organs. The nerve ring does not constitute what is typically considered a cephalopod "brain": the upper portion of the nerve ring lacks differentiated lobes, and most of the nervous tissue appears to focus on finding and consuming food (i.e., it lacks a "higher learning" center).
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The preoperative targeting of proper implantation sites can be accomplished by the indirect and direct methods. The indirect method uses computer tomography, magnetic resonance imaging, or ventriculography to locate the anterior and posterior commissures and then employs predetermined coordinates and distances from the intercommissural line to define the target area. Subsequent histologically defined atlas maps can also be used to verify the target area. The direct method provides visualization and targeting of deep nuclei by applying stereotactic preoperative MRI, which unlike the indirect method, takes into account the anatomic variation of the nuclei’s size, position, and functional segregation amongst individuals.
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Chronic rheumatic heart disease mostly affects the mitral valve, which can become thickened with calcification of the leaflets, often causing fusion of the commissures and chordae tendineae. Other findings of ARF include erythema marginatum (usually over the spine or other bony areas) and a red expanding rash on the trunk and extremities that recurs over weeks to months. Because of the different ways ARF presents itself, the disease may be difficult to diagnose. A neurological disorder, Sydenham chorea, can occur months after an initial attack, causing jerky involuntary movements, muscle weakness, slurred speech, and personality changes.
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When an individual's mouth is at rest, the teeth in the opposing jaws are nearly touching; there is what is referred to as a "freeway space" of roughly 2–3 mm. However, this distance is partially maintained as a result of the teeth limiting any further closure past the point of maximum intercuspidation. When there are no teeth present in the mouth, the natural vertical dimension of occlusion is lost and the mouth has a tendency to overclose. This causes the cheeks to exhibit a "sunken-in" appearance and wrinkle lines to form at the commissures.
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Once the brain is reoriented to these axes, the researchers must also outline the six cortical outlines of the brain: anterior, posterior, left, right, inferior, and superior. In the 1967 atlas the left is with positive coordinates while in the 1988 atlas the left has negative coordinates. By defining standard anatomical landmarks that could be identified on different subjects (the anterior and posterior commissures), it became easier to spatially warp an individual brain image obtained through Magnetic Resonance Imaging (MRI), positron emission tomography (PET) and other imaging methods to this standard Talairach space. One can then make inferences about tissue identity at a specific location by referring to the atlas.
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Simplified diagram of the mollusc nervous system The cephalic molluscs have two pairs of main nerve cords organized around a number of paired ganglia, the visceral cords serving the internal organs and the pedal ones serving the foot. Most pairs of corresponding ganglia on both sides of the body are linked by commissures (relatively large bundles of nerves). The ganglia above the gut are the cerebral, the pleural, and the visceral, which are located above the esophagus (gullet). The pedal ganglia, which control the foot, are below the esophagus and their commissure and connectives to the cerebral and pleural ganglia surround the esophagus in a circumesophageal nerve ring or nerve collar.
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Angular cheilitis Angular cheilitis is inflammation at the corners (angles) of the mouth, very commonly involving Candida species, when sometimes the terms "Candida-associated angular cheilitis", or less commonly "monilial perlèche" are used. Candida organisms alone are responsible for about 20% of cases, and a mixed infection of C. albicans and Staphylococcus aureus for about 60% of cases. Signs and symptoms include soreness, erythema (redness), and fissuring of one, or more commonly both the angles of the mouth, with edema (swelling) seen intraorally on the commissures (inside the corners of the mouth). Angular cheilitis generally occurs in elderly people and is associated with denture related stomatitis.
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This is referred to as a negative cortical tropism because eliciting sensory stimuli, such as would result from tactile contact on the volar aspect of the fingers and palm of the hand, are linked to the activation of movement that reduces or eliminates the eliciting stimulation through a negative feedback connection (see discussion above in section entitled "Parietal and Occipital Lobes"). Each intrahemispheric agency system has the potential capability of acting autonomously in its control over the contralateral limb although unitary integrative control of the two hands is maintained through interhemispheric communication between these systems via the projections traversing the corpus callosum at the cortical level and other interhemispheric commissures linking the two hemispheres at the subcortical level.
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Like most molluscs, B. secunda has a circumesophageal nerve ring or nerve collar composed of its pleural and pedal ganglia and their commissures and connectives within the region of the head. The esophagus passes through this nerve ring on its way back to the stomach; the esophageal pouches and salivary glands are located entirely before it. The cerebral ganglia are also located forward of the ring. Behind the nerve ring, the commissure of the pleural ganglia performs a characteristic "twist" common to many gastropods, the evolutionary result of torsion which placed the anus and the openings of the kidneys ("nephridial openings") near the head of the animal in order to accommodate the ancestral presence of a twisted shell (B.
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In nematodes, the ring consists of only two to four large associative cells connected to two paired lateral ganglia, two ventral ganglia, and a single unpaired dorsal ganglion. Among arthropods, the usual arrangement is a single ganglion (the cerebral) positioned above the esophagus, a single ganglion or nerve mass (the subesophageal) below it, and commissures connecting the two in a ring. Among the gastropods, the evolutionary torsion event which relocates the anus to near the head of the animal and allowing it to withdraw into its shell has relocated the commissure of the pleural ganglia into a "twist" (the right ganglion has relocated to the left side, and the left ganglion to the right).
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Sharpirhynchia sharpi has a small shell, subtrigonal to transverse or laterally elongate in adults; unequally biconvex, dorsal valve more convex than ventral one, subglobose in profile. Lateral commissures oblique ventrally; anterior commissure narrowly uniplicate; linguiform extension developed variably, generally low and U-shaped. No clear sulcation on dorsal umbone. Beak relatively long, acute, and suberect, with slightly incurved tip in adult; foramen big, oval, hypothyridid, with well developed rim; deltidial plates narrow, disjunct to just conjunct; beak ridges subangular; interareas small, but well defined and slightly concave, with fine and clear transverse lines. Ventral valve moderately convex; sulcus shallow and wide, well separated from slopes and with rounded bottom, occurring at posterior 1/3 to 1/2 of valve.
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The VNC contains ascending and descending neurons that relay information to and from the brain, motor neurons that project into the body and synapse onto muscles, sensory neurons that receive information from the body and environment, and interneurons that coordinate circuitry of all of these neurons. The neurons of the VNC are organized into segmental ganglia with the nerve cords running down the ventral ("belly", as opposed to back) plane of the organism. Ventral nerve cords from anterior to posterior (the thoracic and abdominal tagma in the arthropods) are made up of segmental ganglia that are connected by a tract of nerve fibers passing from one side to the other of the nerve cord called commissures. The complete system bears some likeness to a rope ladder.
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Living arthropods have paired main nerve cords running along their bodies below the gut, and in each segment the cords form a pair of ganglia from which sensory and motor nerves run to other parts of the segment. Although the pairs of ganglia in each segment often appear physically fused, they are connected by commissures (relatively large bundles of nerves), which give arthropod nervous systems a characteristic "ladder- like" appearance. The brain is in the head, encircling and mainly above the esophagus. It consists of the fused ganglia of the acron and one or two of the foremost segments that form the head – a total of three pairs of ganglia in most arthropods, but only two in chelicerates, which do not have antennae or the ganglion connected to them.
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The number and nature of the post-oral segments in the insect head have rarely been questioned. A much more difficult area, however, has been the nature of the preoral region. The obvious contradiction between a theory that no-preoral structures are segmental, and evidence, such as for the first antennae of crustaceans, that some such structures clearly are, led workers as long ago as Lankester to posit that there has been forward migration of segments in front of the mouth. Indeed, such a process can be seen in ontogeny of the tritocerebrum, which can be seen to migrate forward as the brain develops; furthermore, although in most insects and crustaceans its ganglia are part of the brain, its commissures still loop behind it, suggesting derivation from a more posterior position.
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The "gull-wing lift" is an effective surgical technique for increasing the prominence (display) of the vermilion coloring of the lips, by removing skin (and other tissues) as required, ether directly from or from above the white line of skin that borders onto, and sets off, the vermilion of the lips (the white roll). The incisions remove tissue and significantly alter the shape of the lips by moving up the vermilion from both peaks of the Cupid's bow outwards to the commissures, the corners of the mouth. Incisions are also made below the lower lip to increase the projection of the vermilion of the lower lip. This gull-wing lip lift usually requires an OR time of approximately 20 minutes; post-operatively, the swelling of the lips subsides at 1–2 weeks and the tightness subsides at 2–4 months.
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The parotid salivary glands appear early in the sixth week of the prenatal development and are the first major salivary glands formed. The epithelial buds of these glands are located on the inner part of the cheek, near the labial commissures of the primitive mouth (from ectodermal lining near angles of the stomodeum in the 1st/2nd pharyngeal arches; the stomodeum itself is created from the rupturing of the oropharyngeal membrane at about 26 days.) These buds grow posteriorly toward the otic placodes of the ears and branch to form solid cords with rounded terminal ends near the developing facial nerve. Later, at around 10 weeks of prenatal development, these cords are canalized and form ducts, with the largest becoming the parotid duct for the parotid gland. The rounded terminal ends of the cords form the acini of the glands.
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Rhynchonelloidella alemanica has small sized shells, subtrigonal to slightly subpentagonal in outline, with wide hinge line; inequivalve, almost plano-convex; dorsal valve markedly everted anteriorly, giving shell subcynocephalous to cynocephalus profile. Lateral commissures deflected ventrally at 15 to 30 degrees; anterior commissure highly uniplicate; linguiform extension high and narrow, top truncated. Beak short, pointed, substraight to suberect; foramen large, oval in shape, hypothyridid, with well developed rim; deltidial plates wide, disjunct to just conjunct; beak ridges angular, extending laterally; interareas well defined and slightly concave with fine growth lines. Ventral valve gently convex at posterior and flattened anteriorly; sulcus well developed, deep and narrow, with flat bottom, occurring at about posterior 1/3 of valve, abruptly separated from slopes and turning over towards dorsal valve sharply at frontal margin, resulting in high linguiform extension. Dorsal valve moderately convex at umbonal region, but less tumid than in Rhynchonelloidella smithi, norelliform stage feebly recognizable, sulcation short or even absent; fold eminent, narrow and well elevated over slopes with steep flanks, occurring at about posterior 1/3 to 1/2 of valve and making valve trilobate anteriorly.
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