. A patient has loss of sensation at angle of mandible (jaw) and parotid area. Which of the following nerve is most likely to be injured.
**Core Concept**
The question is testing knowledge of the **cranial nerves** and their branches, specifically those involved in sensory innervation of the face. The **trigeminal nerve (CN V)** and its branches are key to understanding facial sensation.
**Why the Correct Answer is Right**
The area described, the angle of the mandible and the parotid area, is primarily innervated by the **auriculotemporal nerve**, a branch of the **mandibular division of the trigeminal nerve (V3)**. However, the specific nerve responsible for sensation in this area, particularly the angle of the jaw and over the parotid gland, is the **great auricular nerve**, which originates from the **cervical plexus (C2, C3)**.
**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because it does not specifically match the description of the nerve responsible for the area mentioned.
**Option B:** Incorrect as it does not correspond to the nerve innervating the angle of the mandible and parotid area.
**Option C:** Incorrect because, although the auriculotemporal nerve does provide some sensory innervation to the parotid gland, the description best fits another nerve.
**Clinical Pearl / High-Yield Fact**
The **great auricular nerve** is a significant nerve for the sensation around the ear and the angle of the jaw, often tested in exams due to its relevance in surgical procedures like parotidectomy, where it can be at risk of injury.
**Correct Answer:** D. Great Auricular Nerve