Which cranial nerve is responsible for innervation of the lateral rectus muscle?

The lateral rectus muscle, which is responsible for abduction of the eye (moving the eye outward), is innervated by the abducens nerve (CN VI). This cranial nerve specifically controls the movements of this muscle, allowing for lateral gaze.

Understanding the roles of the other cranial nerves can clarify why the abducens nerve is the correct choice. The oculomotor nerve (CN III) primarily innervates most extraocular muscles, including the medial rectus, superior rectus, inferior rectus, and inferior oblique. The trochlear nerve (CN IV) innervates the superior oblique muscle, which is involved in the downward and inward movement of the eye. The trigeminal nerve (CN V) is mainly responsible for facial sensation and motor functions related to mastication, not eye movement.

In summary, the distinctive role of the abducens nerve in innervating the lateral rectus muscle makes it the correct answer for this question regarding eye movement.