Suboccipital nerve is?
**Core Concept**
The suboccipital nerve is a branch of the suboccipital nerve plexus, which is formed by the posterior ramus of C1 (dorsal ramus of C1). This plexus provides motor innervation to the suboccipital muscles, which are involved in head rotation and extension.
**Why the Correct Answer is Right**
The suboccipital nerve plexus is formed by the posterior ramus of C1, and it gives off branches to the suboccipital muscles, including the rectus capitis posterior major and minor, and the obliquus capitis superior and inferior. These muscles are responsible for rotating the head and extending the neck. The suboccipital nerve also provides sensory innervation to the skin over the occipital region.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because the suboccipital nerve is not a branch of the cervical plexus, which is formed by the ventral rami of C1-C4.
* **Option B:** This option is incorrect because the greater occipital nerve is a branch of the dorsal ramus of C2, not the suboccipital nerve.
* **Option C:** This option is incorrect because the lesser occipital nerve is a branch of the cervical plexus, not the suboccipital nerve.
**Clinical Pearl / High-Yield Fact**
The suboccipital nerve can be compressed, leading to suboccipital neuralgia, a condition characterized by pain and tenderness in the suboccipital region.
**Correct Answer:** D. Suboccipital nerve.