Left posterolateral exposure of the mastoid process. The skin and superficial fascia overlying the mastoid area has been reflected forward. The great auricular nerve supplying sensory innervation to the skin of the ear lobule and angle of the mandible is exposed. Muscles overlying the mastoid and reflected (from superficial to deep) include the sternocleidomastoid, splenius capitis, and longissimus capitis. This exposes the transverse process of the atlas (C1) to which attaches the levator scapulae, the obliquus capitis inferior, and the obliquus capitis superior. The latter muscle takes a nearly horizontal course posteriorly to attach to the inferior nuchal line on the skull posterior to the mastoid process. The tail of the parotid gland is shown overlying the posterior digastric muscle.