Mastoid region

The mastoid region of the skull (or epicranium), located behind and slightly below the external ear canal, overlays the mastoid process of the temporal bone.

This area is externally marked by the mastoid bony prominence and bordered by the temporal line above, the external auditory canal in front, the sternocleidomastoid muscle below, and the occipital region behind.

Clinically, the mastoid process is a key surgical landmark for accessing the posterior cranial fossa and performing mastoidectomies. It is closely related to important structures such as the sigmoid sinus, located deep to the mastoid cortex, and the facial nerve, which exits the skull at the stylomastoid foramen near the mastoid process.

Anatomically, the mastoid region lies posteroinferior to the temple, lateral to the occipital region, and beneath the parietal region.