Overview
The head is divided into the cranial part (brain case) and the facial part, and each is subdivided into topographic regions. This topic describes the regions of the cranial vault, the temporal and parotid regions and the facial regions, with their blood supply and their motor and sensory innervation.
Regions of the cranial vault and the scalp
The cranial vault is divided into the frontal, parietal and occipital regions, which together form the scalp, and the paired temporal regions at the sides. The scalp consists of five layers, remembered as SCALP:
- Skin: thick, hair-bearing and rich in sebaceous glands
- Connective tissue (dense subcutaneous layer): firmly binds the skin to the aponeurosis; contains the vessels and nerves, and its vessels are held open, so scalp wounds bleed heavily
- Aponeurosis (galea aponeurotica): connects the frontal and occipital bellies of the occipitofrontalis
- Loose areolar tissue: the 'danger area', allowing the scalp to move and spreading infection to the emissary veins and the intracranial venous sinuses
- Pericranium: the periosteum of the skull bones
Blood supply: the supratrochlear and supraorbital arteries (from the ophthalmic artery) in front; the superficial temporal and posterior auricular arteries at the sides; the occipital artery behind. Sensory innervation: the supratrochlear, supraorbital, zygomaticotemporal and auriculotemporal nerves (trigeminal) and the lesser, greater and third occipital nerves (cervical). Motor innervation of the occipitofrontalis: the temporal branches and the posterior auricular branch of the facial nerve.