Layers of the Scalp, Blood Supply, and Nerve Supply

The scalp consists of five distinct layers that play crucial roles in protection, sensation, and circulation. Understanding these layers, their blood supply, and nerve supply is vital in clinical settings, especially for surgical procedures and trauma management.

Layers of the Scalp

Skin: The outermost layer, rich in sebaceous glands, sweat glands, and hair follicles.
Connective Tissue: Dense subcutaneous tissue containing vascular structures and nerves.
Aponeurosis (Galea Aponeurotica): Fibrous tissue providing mobility to the scalp.
Loose Areolar Tissue: Facilitates free movement but is vulnerable to infection spread.
Pericranium: The innermost layer directly attached to the skull bones.

Blood Supply to the Scalp

The scalp has an extensive vascular network ensuring adequate perfusion:

Arterial Supply

Branches of the External Carotid Artery: Superficial temporal, occipital, and posterior auricular arteries.
Branches of the Internal Carotid Artery: Supraorbital and supratrochlear arteries.

Venous Drainage

Superficial veins accompany arteries, draining into the external and internal jugular veins.
Diploic veins and emissary veins connect extracranial and intracranial circulation.

Nerve Supply to the Scalp

The scalp receives sensory and motor innervation:

Sensory Nerves

Branches of the Trigeminal Nerve (CN V): Supraorbital, supratrochlear, zygomaticotemporal, auriculotemporal nerves.
Cervical nerves (C2, C3): Greater occipital, lesser occipital, and great auricular nerves.