Oculomotor nucleus

Oculomotor nucleus

The oculomotor nucleus is a cluster of neurons found in the midbrain that plays a crucial role in eye movement. It is responsible for the motor innervation of the majority of the muscles controlling the movements of the eye, except for the superior oblique muscle and the lateral rectus muscle.

Anatomy

The oculomotor nucleus is located in the midbrain, at the level of the superior colliculus. It is situated near the midline, in the gray matter of the floor of the cerebral aqueduct. The nucleus is divided into several subnuclei, each supplying different extraocular muscles.

Function

The primary function of the oculomotor nucleus is to control most of the eye's movements by supplying the extraocular muscles. These muscles include the superior rectus muscle, inferior rectus muscle, medial rectus muscle, inferior oblique muscle, and the levator palpebrae superioris.

The oculomotor nucleus also plays a role in the parasympathetic control of the pupil and the lens of the eye. The Edinger-Westphal nucleus, a part of the oculomotor nucleus, provides parasympathetic fibers to the eye, constricting the pupil and controlling the shape of the lens.

Clinical significance

Damage to the oculomotor nucleus can result in oculomotor nerve palsy, a condition characterized by drooping of the eyelid (ptosis), dilated pupil (mydriasis), double vision (diplopia), and inability to coordinate the movements of both eyes (strabismus). This condition can be caused by various factors, including stroke, brain tumor, aneurysm, or diabetes mellitus.

See also

• Oculomotor nerve
• Midbrain
• Extraocular muscles
• Eye movement