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By: Alexis Derby

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Friday, 11-May-2012 14:59 Email | Share | Bookmark
The Ocular Nerves Oculomotor, Trochlear plus Abducens Nerve

Ocular self-control are the oculomotor, the trochlear plus the abducens self-control. Because they function together inside the regulation of eye movements, they are regarded as ocular self-control and are examined together.The oculomotor nerve (Cranial Nerve III) \nThe Oculomotor nuclei comprise of several paired groups of nerve cells, adjacent to the midline, ventral to the aqueduct of sylvius at the amount of the superior colliculi. A centrally placed number of nerve cells, the Edinger-Westphal nucleus, innervate the pupillary sphincters and ciliary bodies. This is situated more dorsally, and constitutes the parasympathetic portion of the oculomotor nerve. The nerve cells that mediate the action of the ocular muscles display a certain dorso-ventral topographic representation. The nerve fibers program anteriorly from the mesencephalon, medial total he red nucleus, the substantia nigra plus the intellectual peduncle. The nerve emerges within the anterior aspect of the mid-brainsimply above the pons, between your superior cerebellar plus the back intellectual arteries.It penetrates the dura lateral and anterior to the back clinoid process and enters the lateral wall of cavernous sinus. From there, it enters the Orbit from the superior path fissure and provided the levator palpaebrae superioris, the inferior oblique plus the superior, medial and inferior recti muscles. The preganglionic parasympathetic fibers within the Edinger-Westphal nucleus pass as much as the ciliary ganglion, from where the postganglionic fibers provide the pupillary constrictors plus the ciliary muscles which function inside rental.The trochlear nerve (Cranial Nerve IV) \nthis is the smallest of all cranial self-control and is situated simply anterior to the aqueduct inside the mesencephalon instantly above the pons. The fibers bend posteriorly and caudally about the aqueduct and decussate inside the anterior medullary velum. This penetrates the dura posterolateral to the back clinoid process to enter the cavernous sinus where it happens to be lateral and inferior to another nerve. Through the superior Orbital fissure, it enters the Orbit to supply the superior oblique muscle. Paralysis of the nerve causes tiredness of downward and outward movement of the eye and extorsion (rotation of the eyeball outwards).The abducens nerve (Cranial Nerve VI)(Abducent nerve) \nThis nerve comes from the lower element of the pons inside the ground of the next ventricle. The nerve emerges within the brain stem at the pontomedullary junction. It has the longest intracranial program amidst all the cranial self-control and lies between your pons plus the clivus. This pierces the dura at the back sellae, between your back clinoid and apex of the petrous bone to enter the cavernous sinus, inferomedial to another nerve. This enters the Orbit from the superior Orbital fissure to supply the outside (lateral) rectus muscle.The medial long fasciculus: This fiber system unites the nuclei of third, 4th, 5th, 6th, 7th, 8th, 11th plus the 12th cranial self-control plus the engine nuclei of top cervical self-control. Owing to the interconnection isolated eye movments are not possible. Visual, auditory, sensory, vestibular, along with other stimuli produces conjugate change of the eyes and head.Sympathetic innervation: The sympathetic fibers which control oculopupillary action happen within the 8th cervical and first thoracic spinal segments. The preganglionic fibers visit the inferior, center, and superior sympathetic ganglia inside the cut. The postganglionic fibers follow the span of the inner carotid artery and travel along the Ophthalmic split of the third nerve into the orbit. Through the long ciliary self-control, they provide the pupillary dilators. The tarsal muscles, plus the orbital muscle of Muller.Cortical control: The back portion of the next and third frontal convolutions constitute the evolutional cortical control of conjugate ocular movements. A pontine center for lateral gaze has also been described inside the location of the abducens nerve- the parapontine gaze center.Cop\nbandeaux


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