Subcutaneous Hematoma of the Head

Subcutaneous hematoma of the head (from Latin sub- — under, cutis — skin, and Greek haematoma — blood tumor) is a localized collection of extravasated blood located within the layer of adipose tissue strictly between the epidermis and the galea aponeurotica.

In traumatology, this is the most common and least dangerous form of closed head soft tissue injury.

Etiology and pathophysiology

In the event of a direct domestic impact by a blunt object or fall, there is a rupture of small subcutaneous arteries and veins. The extravasated blood enters the layer of subcutaneous adipose tissue (layer “C” in the structure of the scalp).

The main feature of the pathogenesis is the presence of numerous rigid fibrous septa (trabeculae) within this layer, which vertically connect the skin to the aponeurosis. These septa act like a honeycomb, preventing the extravasated blood from spreading laterally. As a result, the blood accumulates locally, stretching the tissues and forming a tense, elevated protrusion above the surface.

Clinical significance

Upon examination, a doctor identifies a dense, round, and severely painful swelling, which moves with the skin when displaced. The hematoma never reaches critical volumes capable of causing systemic blood loss.

There is a classic diagnostic pitfall associated with this condition. Within the first day, the edges of the hematoma become infiltrated with fibrin and become stonily dense, while its center remains filled with soft liquid blood. Upon palpation of such a structure (a dense edge and a depression in the center), an inexperienced clinician may mistakenly suspect a depressed skull fracture. Radiography is always required to rule out a fracture. Treatment of subcutaneous hematoma involves the local application of cold during the first hours to stop bleeding and induce vascular spasm.