Question

Select all that apply

Where does cranial nerve III (the oculomotor nerve) terminate?
a) Constrictor of the iris
b) Retina
c) The ciliary muscle of the lens
d) External eye muscles
e) Superior orbital fissure

Answer 1

The oculomotor nerve terminates in the constrictor of the iris, the ciliary muscle of the lens, and several external eye muscles; it does not terminate in the retina or the superior orbital fissure.

Step-by-step explanation:

The cranial nerve III, known as the oculomotor nerve, terminates in several locations relevant to eye movement and function. Specifically, the oculomotor nerve terminates in the constrictor of the iris, which controls pupil size; the ciliary muscle of the lens, which focuses the lens for near vision; and several external eye muscles, which control most movements of the eye. These muscles include the inferior oblique, medial rectus, superior rectus, and inferior rectus as well as the levator palpebrae superioris, which raises the eyelid.

However, the oculomotor nerve does not terminate in the retina, as the retina is innervated by the optic nerve. Also, while the superior orbital fissure is an important anatomical feature because it allows passage for the oculomotor nerve (among others) to reach its destinations, it is not a termination point.