Cervical Plexus

Lesser Occipital Nerve
Greater Auricular Nerve
Transverse Cervical Nerve
Supraclavicular Nerve

The Cervical Plexus is formed from the anterior roots of spinal nerves C1 - C4. The cervical plexus provides cutaneous branches (lesser occipital, greater auricular, transverse cervical, and supraclavicular), and two named motor branches (ansa cervicalis and phrenic). The cutaneous branches emerge from the posterior border of the sternocleidomastoid to supply the skin. Direct motor branches supply the prevertebral, sternocleidomastoid, and trapezius.

The Lesser Occipital nerve (C2, 3) supplies the skin of the lateral occipital portion of the scalp, the upper medial part of the auricle and the area over the mastoid process.

The Greater Auricular nerve (C2, 3) supplies the skin of the back of the ear and the area over the mastoid process and parotid gland.

The Transverse Cervical nerve (C2, 3) supplies the skin over the anterior portion of the neck.

The Supraclavicular nerves (C3, 4) supply the skin over the clavicle, upper deltoid, and pectoral regions as low as the third rib.

Parasthesia of corresponding dermatomes occurs after injury to the cervical plexus.
The cutaneous nerves of the cervical plexus travel below the "nerve point" (Erb's point) in the middle third at the posterior margin of the sternocleidomastoid. The cutaneous branches pass to the skin in diverging directions through the superficial layer of fascia.