Great auricular nerve

The great auricular nerve is a cutaneous (sensory) nerve of the head. It originates from the second and third cervical (spinal) nerves of the cervical plexus. It provides sensory innervation to the skin over the parotid gland and the mastoid process, parts of the outer ear, and to the parotid gland and its fascia.
Pain resulting from parotitis is caused by an impingement on the great auricular nerve.

Structure

The great auricular nerve is the largest of the ascending branches of the cervical plexus.

Origin

It arises from the second and third cervical nerves, with the predominant contribution coming from C2.''''''

Course and relations

The great auricular nerve is a large trunk that ascends almost vertically over the sternocleidomastoid. It winds around the posterior border of the sternocleidomastoid muscle, then perforates the deep fascia before ascending alongside the external jugular vein upon that sternocleidomastoid muscle beneath the platysma muscle to the parotid gland. Upon reaching the parotid gland, it divides into an anterior branch and a posterior branch.

Branches

Anterior branch
The anterior branch is distributed to the skin of the face over the parotid gland.
It communicates with the facial nerve (CN VII) inside the parotid gland.
Posterior branch
The posterior branch innervates the skin over the mastoid process, on the back of the auricle, of the lobule, and of the lower part of the concha.
The posterior branch communicates with the lesser occipital nerve, the auricular branch of the vagus, and the posterior [auricular branch of the facial].

Distribution

The great auricular nerve is distributed to the skin of the face over the angle of the mandible' and parotid gland,' skin over of the mastoid region' , parts of the auricle,' and the parotid gland and parotid fascia.''''''

Clinical significance

The great auricular nerve may be damaged during surgery on the parotid gland, reducing sensation to the face.
Pain resulting from parotitis is caused by an impingement on the great auricular nerve.
The intermingling of the great auricular nerve and the facial nerve (CN VII) is thought to be responsible for the pathogenesis of Frey's syndrome following parotidectomy.