Subgaleal Space

spatium subgaleale

The subgaleal space is the layer of loose connective tissue beneath the epicranial aponeurosis, the fourth layer of the scalp. It allows the scalp to slide over the skull and contains emissary veins that connect the scalp veins to the venous sinuses inside the skull.

Anatomical Data

Boundaries & Contents

Location	Between the epicranial aponeurosis and the pericranium of the skull vault.
Boundaries	Epicranial aponeurosis above Pericranium below Attachments of occipitofrontalis to the superior nuchal lines and supraorbital margins
Contents	Loose areolar tissue Emissary veins

Biomechanics

Function & Actions

Allows the scalp to move freely over the skull.

Clinical Relevance

Clinical Notes

It is often called the danger area of the scalp because infection here can spread through emissary veins into the skull. Blood can collect here after head injury, and in newborns a subgaleal haemorrhage after vacuum delivery can be large enough to cause shock. Scalping injuries occur through this layer.

Pathology

Common Injuries & Conditions

Subgaleal Haemorrhage

Bleeding into the loose subgaleal layer, especially in newborns after instrumental delivery, which can spread across the whole scalp and cause dangerous blood loss.

Scalp Infection Spreading Intracranially

Infection in the subgaleal space can pass via emissary veins to cause meningitis or venous sinus thrombosis.

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