Where is oculomotor nerve

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Gross anatomy Nuclei There are two cranial nerve nuclei whose neurons contribute axons to the oculomotor nerve: The oculomotor nucleus lies in the midbrain anterior to the periaqueductal grey matter at the level of the superior colliculus anterior to the cerebral aqueduct. The fibers run through the tegmentum , red nucleus and medial aspect of the substantia nigra. The Edinger-Westphal nucleus contributes parasympathetic fibers to the oculomotor nerve which synapse at the ciliary ganglion.

It is a small nucleus located between the oculomotor nucleus and the periaqueductal grey matter. Cisternal portion The nerve emerges from the medial aspect of the cerebral peduncle to enter the interpeduncular cistern. Cavernous sinus portion Within the cavernous sinus the oculomotor nerve is located uppermost, above the trochlear nerve in the lateral wall of the sinus.

Orbital portion It enters the orbit via the superior orbital fissure as two branches: superior division and inferior division, with the nasociliary nerve a branch of the ophthalmic division of the trigeminal nerve between them and the abducens nerve CN VI below all three. Superior division The superior division, the smaller of the two, runs above the optic nerve and gives branches to superior rectus and levator palpebrae superioris muscles which it supplies with motor fibers.

Inferior division The inferior division supplies the inferior rectus , medial rectus this branch passes below the optic nerve , and the inferior oblique. Related pathology oculomotor nerve palsy. Quiz questions. Last's Anatomy. Churchill Livingstone. Read it at Google Books - Find it at Amazon 2. Clemente CD. Read it at Google Books - Find it at Amazon 3.

Clemente C. Anatomy of the human body. Read it at Google Books - Find it at Amazon. Related articles: Anatomy: Brain. Promoted articles advertising. Figure 1: midbrain anatomy Figure 1: midbrain anatomy. Figure 2: brain stem nuclei Figure 2: brain stem nuclei. As a mixed nerve, the oculomotor nerve supplies motor function and parasympathetic function. It does not have any sensory function, which has to do with sensation. Motor function means movement, and the oculomotor nerve is responsible for much of the movement associated with your eyes.

The muscles innervated by the superior branch and its offshoots are around your eye inside the orbital. The sympathetic fibers from the internal carotid plexus that travel with the oculomotor nerve provide motor function to the superior tarsal muscle , which keeps the eyelid open once the levator palpabrae superioris raises it.

The inferior branch and its offshoots innervate:. Parasympathetic function has to do with the parasympathetic nervous system, whose functions tend to oppose and balance those of the sympathetic nervous system. The sympathetic nervous system takes over during stressful or dangerous situations and is responsible for "fight or flight" functions, such as increasing your adrenaline levels and dilating your eyes.

When the parasympathetic nervous system is in control, it's often referred to as "rest and digest" mode. It lowers your heart rate to conserve energy, aids with optimal function of your intestines, and returns your pupils to their normal size. The parasympathetic fibers from the oculomotor nerve innervate two muscles inside the iris:. The oculomotor nerve can be damaged or paralyzed in numerous ways.

This is called acquired oculomotor palsy and is different from congenital oculomotor palsy, which was discussed above. Acquired oculomotor palsy can be caused by:.

Symptoms of damage to the oculomotor nerve include:. Depending on the cause, immediate treatment of oculomotor nerve palsy is typically conservative. Depending on the specific symptoms and the part s of the nerve that's damaged, it may include:. If this approach hasn't lead to much improvement after six months, surgery may be considered.

Surgery involves cutting and repositioning the muscles so that functional muscles can take over for those that aren't working properly. Sign up for our Health Tip of the Day newsletter, and receive daily tips that will help you live your healthiest life. JAMA Ophthalmol. Anatomy Next. Neuroanatomy, Cranial Nerve 3 Oculomotor. In: StatPearls [Internet].

Leanage N. TeachMe Anatomy. Updated March 13, Rubin M. Third Cranial Oculomotor Nerve Disorders. Merck Manual: Professional Version. Updated June, Your Privacy Rights. To change or withdraw your consent choices for VerywellHealth.

At any time, you can update your settings through the "EU Privacy" link at the bottom of any page. These choices will be signaled globally to our partners and will not affect browsing data. We and our partners process data to: Actively scan device characteristics for identification. I Accept Show Purposes. Table of Contents View All. Table of Contents. Associated Conditions. The 12 Cranial Nerves. When symptoms of congenital oculomotor palsy are present at birth, it may be a sign of other serious malformations, such as: PHACE syndrome, which is characterized by multiple congenital abnormalities Type 2 neurofibromatosis, which is characterized by the growth of noncancerous tumors in the nervous system Klippel-Trenaunay syndrome, a condition that affects the development of blood vessels, bones, skin, and muscles.

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