Corpus: Lesser occipital nerve

The lesser occipital nerve is a sensory nerve branch of the cervical plexus and contains fibers from the C2 and C3 spinal segments.

The lesser occipital nerve supplies the skin of the lower lateral occipital region and the area behind the ear (retroauricular region).

Originating from the anterior branches of the 2nd and 3rd spinal nerves, the lesser occipital nerve wraps around the sternocleidomastoid muscle. It emerges at the posterior edge of this muscle, along with the transverse cervical nerve, the greater auricular nerve, and the supraclavicular nerves, in a region known as Erb's point. It then ascends along the posterior edge of the sternocleidomastoid muscle. Near the skull, it pierces the superficial cervical fascia and continues upward into its supply area in the lateral occipital and retroauricular regions. In these areas, it communicates with the greater auricular nerve, the greater occipital nerve, and the posterior auricular nerve.

Injuries to the lesser occipital nerve can lead to loss of sensation or occipital neuralgia, which manifests as headaches. Causes of such injuries include neck surgeries, trauma, herpes zoster infection, or nerve compression by a tumor.