![]() Managing oculomotor nerve palsy.Arch Ophthalmol.1998 116(6):798. Early progression of ophthalmoplegia in patients with ischemic oculomotor nerve palsies.Arch Ophthalmol.1995 113(12):1535–1537. Therefore, a “blown” pupil is treated emergently and requires neuro-imaging, but the lack of this sign does not exclude an acute space-occupying pathology.Īdditional etiologies of 3 rd nerve palsy to consider include Myasthenia Gravis, Thyroid disease, internuclear ophthalmoplegia, orbital tumor or pseudotumor, and temporal arteritis (giant cell arteritis). Retrospective review studies have shown that we cannot completely rely upon the pupil to differentiate vascular from compressive causes because numerous exceptions have occurred. In fact, an acutely “blown” pupil in conjunction with the above mentioned ptosis and motility deficits may be an ominous sign of a growing aneurysm. However, a compressive or space-occupying lesion such as an aneurysm or tumor would cause disruption of the parasympathetic fibers because of their superficial location on the outside of CN III. Pretectal neurons project excitatory synapses to the ipsilateral and contralateral EdingerWestphal nucleus, which contains parasympathetic preganglionic. These presentations typically have ptosis, a down-and-out eye but a normal pupil. Most lesions of the 3 rd cranial nerve are from vascular insults causing ischemia and can be attributed to known vascular risk factors such as diabetes or hypertension. Understanding the anatomy of CN III is important to deciphering important the etiology of a CN III palsy. A dilated pupil (mydriasis) resulting from disruption of the parasympathetic fibers are the result of denervation of the sphincter pupillae. The levator palpebrae superioris muscle, which is the primary muscle in elevating the eyelid is innervated by the superior division of CN III.Ī complete lesion of CN III would result in ipsilateral ptosis (droopy eyelid) and a “down and out” eye due to denervation of most extraocular muscles leaving the lateral rectus (innervated by CN VI, abducts) and superior oblique (innervated by CN IV, depresses) unopposed. causing pupillary constriction when activated. ![]() Parasympathetic nerve fibers originating from the Edinger-Westphal nucleus travel circumferentially with CN III to the pupil. The third cranial nerve innervates four of the six extraocular muscles: medial rectus, superior rectus, inferior rectus, and inferior oblique. Adie syndrome.Home / Basic Ophthalmology Review / Extraocular Muscles / MotilityĪuthor: Patrick Commiskey, 4 th Year Medical Student, University of Michigan Medical Schoolĭescription: The 3 rd cranial nerve (CN III), or oculomotor nerve, is a motor nerve responsible for many eye-related functions. National Organization for Rare Disorders. Exits via Superior Orbital Fissure (with IV, V1, VI). Parasympathetic innervation to the head and neck. Pupillary constriction (sphincter pupillae: Edinger Westphal nucleus), accommodation, eyelid opening (levator palpebrae). Overview of the anatomy, physiology, and pharmacology of the autonomic nervous system. The autonomic portion of CNIII originates from the Edinger-Westphal subnucleus. The levator palpebrae superioris muscle, which is the primary muscle in elevating the eyelid is innervated by the superior division of CN III. ![]() Anatomical variations of the ciliary ganglion with an emphasis on the location in the orbit. All fibers from the midbrain and anterior now serve the same side of the body. Parasympathetic nerve fibers originating from the Edinger-Westphal nucleus travel circumferentially with CN III to the pupil. The parasympathetic pathway for pupillary constriction begins in the Edinger-Westphal nucleus in the. 9 Neurophysiology Pupillary light reflex This section needs expansion. In our review of the literature, we have not found any other such case. Walsh and Hoyt's clinical neuro-ophthalmology, 6th ed. Lippincott Williams & Wilkins 2005:673-674. Reason for referral to ophthalmology: Dilated pupil. The EdingerWestphal nucleus supplies preganglionic parasympathetic fibers to the eye, constricting the pupil, accommodating the lens, and convergence of the eyes. We describe the clinical observation of isolated pupil involvement, attributed to a lesion of the Edinger-Westphal nucleus as a consequence of a mesencephalic haematoma in the context of closed craneo-encephalic trauma. Kardon R. Chapter 14: Anatomy and physiology of the autonomic nervous system. In: Miller NR, Newman NJ, Biousse V, Kerrison JB, eds. Anatomical study of the roots of cranial parasympathetic ganglia: a contribution to medical education. 4 The midline unpaired complex contains the parasympathetic Edinger-Westphal nucleus rostrally, which supplies pupillary constrictor fibers. Lovasova K, Sulla IJ, Bolekova A, Sulla I, Kluchova D. ![]()
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