Nerve supply of temporalis muscle:
**Core Concept**
The temporalis muscle is one of the muscles of mastication, responsible for elevating the mandible and closing the jaws. The nerve supply of this muscle is crucial for its function and innervation.
**Why the Correct Answer is Right**
The temporalis muscle receives its nerve supply from the **deep temporal nerves**, which are branches of the **mandibular division of the trigeminal nerve (V3)**. The deep temporal nerves provide motor innervation to the temporalis muscle, enabling it to contract and perform its masticatory functions. This nerve supply is essential for the coordination of jaw movements and the proper functioning of the masticatory apparatus.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because the temporalis muscle does not receive its nerve supply from the **facial nerve (VII)**. The facial nerve primarily provides motor innervation to the muscles of facial expression, not the muscles of mastication.
* **Option B:** This option is incorrect because the **maxillary division of the trigeminal nerve (V2)** primarily provides sensory innervation to the face, including the skin and mucous membranes, but not motor innervation to the muscles of mastication.
* **Option C:** This option is incorrect because the **cervical plexus** primarily provides motor innervation to the muscles of the neck and shoulder region, not the muscles of mastication.
**Clinical Pearl / High-Yield Fact**
The temporalis muscle is one of the muscles of mastication, and its nerve supply is crucial for its function. The deep temporal nerves, branches of the mandibular division of the trigeminal nerve (V3), provide motor innervation to the temporalis muscle, enabling it to contract and perform its masticatory functions.
**Correct Answer: C. Cervical plexus**