Lateral rectus is supplied by:
**Core Concept**
The lateral rectus muscle is one of the six extraocular muscles responsible for eye movement. It is innervated by a cranial nerve that controls the movement of the eyeball.
**Why the Correct Answer is Right**
The lateral rectus muscle is supplied by the abducens nerve, which is the sixth cranial nerve (CN VI). The abducens nerve originates in the pons and traverses the cavernous sinus before entering the orbit. It then innervates the lateral rectus muscle, which is responsible for abduction of the eyeball. The abducens nerve also has a role in the coordination of eye movements, particularly in the convergence of the eyes.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because the trochlear nerve (CN IV) innervates the superior oblique muscle, not the lateral rectus muscle.
* **Option B:** This option is incorrect because the oculomotor nerve (CN III) innervates the medial rectus, superior rectus, inferior rectus, and inferior oblique muscles, but not the lateral rectus muscle.
* **Option D:** This option is incorrect because the trigeminal nerve (CN V) is responsible for sensory innervation of the face and motor innervation of the muscles of mastication, but not the lateral rectus muscle.
**Clinical Pearl / High-Yield Fact**
The abducens nerve is unique in that it is the only cranial nerve that has a longer intracranial course than its extraocular muscle. This can make it vulnerable to compression or damage, leading to lateral rectus palsy.
**Correct Answer:** C.