The cervical plexus is a network of spinal nerve fibers that supply the region of the neck. It consists of fibers from the ventral rami of nerves from C1 to C5. Their branches innervate the skin of the neck and head, as well as the diaphragm and some muscles of neck. The cervical plexus gives off six important nerves:
1) the lesser occipital nerve, which supply the skin of lateral scalp;
2) the greater auricular nerve, which innervates the skin around the external ear;
3) the transverse cervical nerve (also called superficial cervical N.), supplying the skin of ventral and lateral neck;
4) the ansa cervicalis, which is a nerve loop that gives off branches to supply the omohyoid, sternohyoid, and the sternothyroid muscle;
5) the supraclavicular nerve, which innervates the skin of shoulder and central chest;
6) the phrenic nerve, which innervates the diaphragm. The origin of this nerve is found in grey nuclei located in the medulla oblongata and pons.
