All the muscles of the face are supplied by facial nerve, except
**Core Concept**
The facial nerve, also known as cranial nerve VII, is responsible for controlling the muscles of facial expression, among other functions. The muscles of facial expression include the frontalis, orbicularis oculi, orbicularis oris, and others.
**Why the Correct Answer is Right**
The facial nerve innervates the muscles of facial expression through its buccal and marginal mandibular branches. These branches provide motor innervation to the muscles, allowing for voluntary facial movements such as smiling, frowning, and raising the eyebrows. The facial nerve also provides sensory innervation to the taste buds on the anterior two-thirds of the tongue and the motor innervation to the stapedius muscle in the middle ear.
**Why Each Wrong Option is Incorrect**
**Option A:** The muscles of the face are also supplied by other nerves, but this is not an exception. The facial nerve primarily innervates the muscles of facial expression.
**Option B:** The trigeminal nerve (cranial nerve V) supplies the muscles of mastication (chewing) and some muscles of facial sensation, but not the muscles of facial expression.
**Option C:** The hypoglossal nerve (cranial nerve XII) supplies the muscles of the tongue, but not the muscles of facial expression.
**Option D:** The accessory nerve (cranial nerve XI) supplies the sternocleidomastoid and trapezius muscles, but not the muscles of facial expression.
**Clinical Pearl / High-Yield Fact**
The facial nerve can be tested by assessing the patient's ability to smile, frown, and raise their eyebrows. A weakness or paralysis of the facial nerve can result in a "crooked" smile or difficulty closing the eyelids.
**Correct Answer:** B. The trigeminal nerve supplies the muscles of mastication and some muscles of facial sensation, but not the muscles of facial expression.