The third occipital nerve is a branch of the posterior ramus of the C3 spinal nerve, pierces the semispinalis capitis and trapezius muscles, and supplies a small area of the lower part of the scalp.
Arteries supplying the scalp (Fig. 8.74) are branches of either the external carotid artery or the ophthalmic artery, which is a branch of the internal carotid artery.
Branches from the ophthalmic artery