Posterior belly of digastric is supplied by –
**Core Concept**
The posterior belly of the digastric muscle is a unique anatomical structure with distinct innervation characteristics. This muscle is part of the digastric muscle, which has both anterior and posterior bellies, and is involved in the movement of the mandible. The innervation of this muscle is crucial for its function.
**Why the Correct Answer is Right**
The posterior belly of the digastric muscle is supplied by the facial nerve (cranial nerve VII). The facial nerve is a mixed nerve that provides motor innervation to the muscles of facial expression, as well as sensory innervation to the anterior two-thirds of the tongue and other areas. The motor fibers that innervate the posterior belly of the digastric muscle branch off from the main trunk of the facial nerve, specifically from the nerve's mandibular division.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not accurately represent the nerve supply of the posterior belly of the digastric muscle.
**Option B:** This option is incorrect because the auriculotemporal nerve, a branch of the mandibular division of the trigeminal nerve, provides sensory innervation to the area, but not motor innervation to the posterior belly of the digastric muscle.
**Option C:** This option is incorrect because the trigeminal nerve, specifically its mandibular division, provides motor innervation to the muscles of mastication, but not to the posterior belly of the digastric muscle.
**Clinical Pearl / High-Yield Fact**
It's essential to remember that the facial nerve's motor fibers are responsible for the innervation of the posterior belly of the digastric muscle, which is a key landmark for surgeons and anatomists. This knowledge is crucial for understanding the anatomy and function of the facial nerve and its branches.
**Correct Answer:** C. The facial nerve (cranial nerve VII) supplies the posterior belly of the digastric muscle.