Occipital myotome gives
**Core Concept**
The occipital myotome is a specific group of muscles innervated by the nerves that arise from the spinal cord at the level of C1-C3. This concept is essential in understanding the dermatomal and myotomal distribution of the nervous system.
**Why the Correct Answer is Right**
The occipital myotome is responsible for the innervation of the muscles of the posterior cranium, including the occipitalis muscle, which is involved in the movement of the scalp. The nerves that arise from the spinal cord at the level of C1-C3, specifically the greater and lesser occipital nerves, provide motor innervation to these muscles. **Option C: Occipitalis muscle** is the correct answer because it is the primary muscle responsible for the movement of the scalp, and it is innervated by the occipital myotome.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because the muscles of the face are primarily innervated by the cranial nerves, specifically the facial nerve (cranial nerve VII).
* **Option B:** This option is incorrect because the sternocleidomastoid muscle is innervated by the accessory nerve (cranial nerve XI), not the occipital myotome.
**Clinical Pearl / High-Yield Fact**
It's essential to remember that the dermatomal and myotomal distribution of the nervous system can be used to localize neurological deficits to specific spinal cord levels or nerve roots.
**Correct Answer: C. Occipitalis muscle**