Oculomotor nerve

Definition

The oculomotor nerve is the third cranial nerve (CN III) responsible for controlling most of the eye's movements, including constriction of the pupil and maintaining an open eyelid. It originates in the midbrain and innervates muscles that perform eye movements and pupil response.

Related terms

Cranial Nerves: Twelve pairs of nerves that originate in the brain and serve sensory and motor functions mainly in the head and neck region.

Pupil Constriction: The narrowing of the pupil, controlled by the iris sphincter muscle, typically in response to bright light or focusing on nearby objects.

Midbrain: A portion of the brainstem involved in vision, hearing, motor control, sleep/wake, arousal (alertness), and temperature regulation