Oculomotor nerve supplies all of the following except
**Core Concept**
The oculomotor nerve (cranial nerve III) is a complex nerve responsible for controlling several extraocular muscles, including the levator palpebrae superioris muscle, which elevates the upper eyelid. It also carries parasympathetic fibers that regulate pupillary constriction and accommodation.
**Why the Correct Answer is Right**
The correct answer will be the muscle or structure that is not innervated by the oculomotor nerve. The oculomotor nerve innervates the superior rectus, medial rectus, inferior rectus, inferior oblique, and levator palpebrae superioris muscles. It also carries parasympathetic fibers that synapse in the ciliary ganglion and then travel via the short ciliary nerves to the ciliary muscle and sphincter pupillae muscle. The parasympathetic fibers are responsible for pupillary constriction and accommodation.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because the oculomotor nerve does indeed innervate the levator palpebrae superioris muscle, which elevates the upper eyelid.
* **Option B:** This option is incorrect because the oculomotor nerve does indeed innervate the superior rectus muscle, which is responsible for elevating the eye.
* **Option C:** This option is incorrect because the oculomotor nerve does indeed innervate the medial rectus muscle, which is responsible for adduction of the eye.
* **Option D:** This option is incorrect because the oculomotor nerve does indeed innervate the inferior oblique muscle, which is responsible for rotating the eye upward and outward.
**Clinical Pearl / High-Yield Fact**
The oculomotor nerve is often affected in conditions such as third nerve palsy, which can result in ptosis (drooping eyelid), diplopia (double vision), and inability to move the eye upward, downward, or medially. It's essential to identify the affected nerve and diagnose the underlying cause to provide appropriate treatment.
**Correct Answer:** D.