Cranial nerve III

Cranial Nerve III

Cranial Nerve III, also known as the Oculomotor Nerve

The Cranial Nerve III, also known as the Oculomotor Nerve, is the third paired cranial nerve in the human body. It is responsible for the majority of the eye's movements and for the constriction of the pupil and maintaining an open eyelid.

Anatomy

The Oculomotor Nerve originates in the midbrain, which is located near the base of the brain. It then travels through the cavernous sinus and enters the orbit (eye socket) via the superior orbital fissure.

The path of the Oculomotor Nerve

Function

The Oculomotor Nerve is responsible for innervating the majority of the muscles controlling the movements of the eye. These muscles include the superior rectus, inferior rectus, medial rectus, inferior oblique, and levator palpebrae superioris. It also provides parasympathetic innervation to the pupil and the lens of the eye, controlling the constriction of the pupil and the shape of the lens.

Clinical Significance

Damage to the Oculomotor Nerve can result in oculomotor nerve palsy, which can cause double vision, inability to coordinate the movements of both eyes (strabismus), and drooping of the eyelid (ptosis).

See Also

• Cranial nerves
• Oculomotor nerve palsy
• Eye movements