All the following branches of the Vth nerve supply the dura mater except –
**Core Concept**
The trigeminal nerve (Vth nerve) has three main branches: ophthalmic (V1), maxillary (V2), and mandibular (V3). These branches provide sensory innervation to various structures of the face, including the dura mater, which is a protective layer covering the brain and spinal cord.
**Why the Correct Answer is Right**
The auriculotemporal nerve is a branch of the mandibular division of the trigeminal nerve. It primarily supplies the temporal region, including the temporal fascia and the auricle, but not the dura mater. The auriculotemporal nerve is also notable for its role in transmitting parasympathetic fibers to the parotid gland. In contrast, the anterior and posterior ethmoidal nerves, which are branches of the ophthalmic division (V1), do supply the dura mater in the anterior cranial fossa.
**Why Each Wrong Option is Incorrect**
**Option A:** The anterior ethmoidal nerve does supply the dura mater, particularly in the anterior cranial fossa.
**Option B:** The posterior ethmoidal nerve also supplies the dura mater, specifically in the anterior cranial fossa.
**Option D:** Although the mandibular division (V3) does not supply the dura mater directly, the question is asking for an exception, and the auriculotemporal nerve is the correct answer. However, the other branches of the mandibular division, such as the inferior alveolar nerve and the lingual nerve, do provide sensory innervation to the dura mater in certain areas.
**Clinical Pearl / High-Yield Fact**
When recalling the branches of the trigeminal nerve, remember that the anterior and posterior ethmoidal nerves are responsible for supplying the dura mater in the anterior cranial fossa, while the ophthalmic division (V1) also provides sensory innervation to the nasal cavity and the lacrimal gland.
**✓ Correct Answer: C. Auriculotemporal**