Oculomotor nucleus corresponds to which cranial nerve number?

Oculomotor nucleus corresponds to which cranial nerve number?

• A. CN I
• B. CN II
• C. CN III
• D. CN IV

Answer: (C)

The oculomotor nucleus is the motor nucleus for the third cranial nerve. Located in the midbrain, this nucleus gives rise to fibers that innervate most of the eye’s external muscles—medial, superior, and inferior rectus, and inferior oblique—as well as the levator palpebrae superioris for eyelid elevation. It also has parasympathetic fibers that travel with the oculomotor nerve to control pupil constriction and lens focusing (via the Edinger-Westphal pathway). So, the nucleus corresponds to cranial nerve number three.

The oculomotor nucleus is the motor nucleus for the third cranial nerve. Located in the midbrain, this nucleus gives rise to fibers that innervate most of the eye’s external muscles—medial, superior, and inferior rectus, and inferior oblique—as well as the levator palpebrae superioris for eyelid elevation. It also has parasympathetic fibers that travel with the oculomotor nerve to control pupil constriction and lens focusing (via the Edinger-Westphal pathway). So, the nucleus corresponds to cranial nerve number three.