4 – The cutaneous nerves of the superficial cervical plexus

Lesser occipital nerve (C2 nerve root) innervates the superior posterior cutaneous surface of the auricle and the cutaneous surface of the mastoid

Great auricular nerve (C2-C3 nerve roots) innervates the skin overlying the parotid gland, the external acoustic meatus, and the lower surface of the ear

Transverse cervical nerve (C2-C3 nerve roots) innervates the anterior and lateral aspects of the neck with ascending and descending branches

Supraclavicular nerve (C3-C4 nerve roots) innervates the skin above and below the clavicle, the sternoclavicular joint (medial branch), and the acromioclavicular joint (lateral branch)