Great auricular nerve

The great auricular nerve (Latin: nervus auricularis magnus) is the largest ascending sensory cutaneous branch of the cervical plexus. It originates from the anterior (ventral) rami of the second and third cervical spinal nerves (C2 and C3), arising behind the middle portion of the sternocleidomastoid muscle (SCM).

Like the lesser occipital nerve, the great auricular nerve also curves around the posterior border of the SCM, emerging on its lateral surface at the punctum nervosum (Erb’s point). It perforates the deep cervical fascia and, together with the lesser occipital, supraclavicular and transverse cervical nerves becomes superficial. The exit of the great auricular nerve at the Erb’s point is located inferior to the spinal accessory nerve (CN XI).

The great auricular nerve ascends towards the skull, going vertically across the lateral surface of the sternocleidomastoid along the external jugular vein. The nerve is located beneath the platysma muscle. Upon reaching the inferior pole of the parotid gland at the level of the mandibular angle, the great auricular nerve divides into two terminal branches - anterior and posterior.

The anterior (facial) branch innervates the skin over the parotid gland. Within the parotid gland, it gives small twigs that communicate with the facial nerve (CN VII). Some scientists have also reported a rare anatomical variant where the anterior branch of the great auricular nerve anastomoses with the marginal mandibular branch of the facial nerve in the submandibular triangle.

The posterior (mastoid) branch innervates the skin over the mastoid process of the temporal bone and the lower posterior aspect of the auricle (the upper posterior part is innervated by the lesser occipital nerve). The auricular lobule and concha also receive sensory innervation from the posterior branch via its small lateral filament.

Occasionally, the posterior branch of the great auricular nerve can originate from the cervical plexus independently. In that case, it ascends between the lesser occipital and great auricular nerves. The posterior branch connects with the auricular branch of the vagus nerve (CN X), the posterior auricular branch of the facial nerve (CN VII) and the lesser occipital nerve. It should be mentioned that such surgical procedures as parotid and submandibular gland excisions hold great risk of damaging the posterior branch of the great auricular nerve.

References:

1. Gray, H., & Carter, H. (2021). Gray’s Anatomy (Leatherbound Classics) (Leatherbound Classic Collection) by F.R.S. Henry Gray (2011) Leather Bound (2010th Edition). Barnes & Noble.
2. Tubbs, S. R., Rizk, E., Shoja, M., Loukas, M., Barbaro, N., & Spinner, R. J. (2015). Nerves and Nerve Injuries: Vol 1: History, Embryology, Anatomy, Imaging, and Diagnostics (1st ed.). Academic Press.
3. Rea, P. (2016). Essential Clinically Applied Anatomy of the Peripheral Nervous System in the Head and Neck (1st ed.). Academic Press.