Patient has loss of sensation at angle of mandible and parotid area. Which of the following nerve is most likely to be injured
**Core Concept**
The question is testing the student's knowledge of the innervation of the facial region, specifically the trigeminal nerve's division and its branches. The trigeminal nerve is responsible for sensation in the face, and its branches supply the skin over the face, including the angle of the mandible and the parotid area.
**Why the Correct Answer is Right**
The correct answer is likely the **inferior alveolar nerve (IAN)**, which is a branch of the mandibular division (V3) of the trigeminal nerve. The IAN supplies sensation to the skin over the angle of the mandible and the parotid area, as well as the lower teeth. The IAN is at risk during surgical procedures in the mandible, such as tooth extractions or dental implant placement.
**Why Each Wrong Option is Incorrect**
**Option A:** The **maxillary nerve (V2)**, another branch of the trigeminal nerve, supplies sensation to the upper teeth and the skin over the middle third of the face, but not the angle of the mandible or the parotid area.
**Option B:** The **mandibular nerve (V3)**, the main trunk of the trigeminal nerve's mandibular division, supplies sensation to the lower third of the face, but its branches, including the IAN, are responsible for the specific areas in question.
**Option C:** The **facial nerve (CN VII)**, responsible for motor control of facial muscles and taste to the anterior two-thirds of the tongue, does not supply sensation to the skin over the angle of the mandible or the parotid area.
**Clinical Pearl / High-Yield Fact**
The inferior alveolar nerve is at risk during surgical procedures in the mandible, such as tooth extractions or dental implant placement, which can result in numbness or loss of sensation in the area supplied by the IAN.
**Correct Answer: C. Facial nerve (CN VII)**