Deep (and Superficial) Cervical Plexus

Abstract

The anterior branches of the four upper cervical spinal nerves (C1 to C4) form the cervical plexus (Figs. 15.1 and 15.2), which is covered by the sternocleidomastoid muscle. The branches of the cervical plexus carry motor, sensory, proprioceptive, and autonomous fibers and divide into superficial cutaneous branches penetrating the cervical fascia and deeper muscular branches that mainly innervate the joints and muscles. The cutaneous branches of the cervical plexus are the lesser occipital nerve, great auricular nerve, transverse cervical (colli) nerve, and the supraclavicular nerves (Fig. 15.3). The lesser occipital nerve (from C2 and C3) passes on the splenius capitis muscle to its insertion area, where it fans out into several branches and supplies the skin on the upper side of the neck and upper part of the auricle and the adjoining skin of the scalp. The largest plexus branch is usually the great auricular nerve (from C2 and C3), which passes upward behind the external jugular vein and divides into a posterior and an anterior end branch. The posterior branch supplies the skin lying behind the ear and the medial and lateral surfaces of the lower part of the auricle. The anterior branch supplies the skin in the lower posterior part of the face and the concave surface of the auricle. The transverse cervical nerve (from C2 and C3) passes almost horizontally over the external surface of the sternocleidomastoid muscle in an anterior direction toward the hyoid bone, divides into superior and inferior branches, and supplies the skin over the anterolateral side of the neck between the mandible and the sternum. The common trunk of the supraclavicular nerves (from C3 and C4) appears at the posterior margin of the sternocleidomastoid muscle, just below the transverse cervical nerve; passes downward; and divides into anterior, medial, and posterior supraclavicular nerve branches. The areas supplied by the supraclavicular nerves include the skin over the caudal part of the neck and the skin above the shoulders and the lateral upper chest, as well as the skin covering the anterior part of the deltoid muscle and occupying the acromial region.