There are five layers to the scalp:

• Skin
• Connective tissue (vascular)
• Aponeurosis
• Loose connective tissue
• Periosteum

The superficial three layers are tightly bound so that the scalp slides over the cranium only because of the underlying layer of loose areolar connective tissue.

CLINICAL CORNER: SCALP WOUNDS

The dense fibrous subcutaneous tissue tends to hold the walls of superficial blood vessels open when cut, so scalp wounds tend to bleed heavily and require suturing. Transverse wounds that penetrate the aponeurosis will gape due to the pull of occipitalis and frontalis, whereas sagittal tears are more easily sutured. All such wounds are still serious because infections can easily spread once they enter the loose connective tissue layer.