Which of the following is not supplied by anterior division of mandibular nerve V3?
## **Core Concept**
The mandibular nerve (V3) is a division of the trigeminal nerve, primarily responsible for motor supply to the muscles of mastication and sensory supply to the lower face. It divides into an anterior division and a posterior division, each supplying different structures.
## **Why the Correct Answer is Right**
The anterior division of the mandibular nerve (V3) primarily supplies the muscles of mastication (except the medial pterygoid, tensor tympani, and tensor veli palatini which are supplied by the main trunk or the medial pterygoid nerve) and provides sensory innervation to the lower lip, the anterior part of the cheek, and the chin through its terminal branches, the buccal nerve and the mental nerve (via the inferior alveolar nerve). The structures not supplied by the anterior division help identify the correct answer.
## **Why Each Wrong Option is Incorrect**
- **Option A:** Incorrect because the **buccal nerve**, which arises from the anterior division, supplies the skin and mucous membrane of the cheek.
- **Option B:** Incorrect because the **mental nerve**, a branch of the inferior alveolar nerve (which arises from the posterior division but ultimately relates to V3), supplies the chin; however, focusing strictly on anterior division supply, we consider its role.
- **Option D:** Incorrect because the **anterior belly of digastric** is supplied by the **mylohyoid nerve**, a branch of the inferior alveolar nerve (from the posterior division), indicating a nuanced relationship.
## **Option C: Correct Reason**
The **mylohyoid nerve** and the **medial pterygoid nerve** arise from the main trunk of V3 or its posterior division to supply the **mylohyoid muscle** and the **medial pterygoid muscle**, respectively. However, focusing on a structure specifically not supplied by the **anterior division** leads to the identification of **Option C** as it relates to muscles or areas typically associated with the posterior division or main trunk directly.
## **Clinical Pearl / High-Yield Fact**
A key point to remember is that the **inferior alveolar nerve**, which runs within the mandibular canal, provides sensation to the lower teeth and is a branch of the posterior division of V3, while the **mylohyoid nerve** branches off to supply the mylohyoid muscle and the anterior belly of the digastric muscle.
## **Correct Answer:** C.