ABSTRACT
Scalp The scalp is vascular, hair-bearing skin; at its base is a thick fibrous membrane called the galea aponeurotica. Lying between the galea and the skull is a very thin sheet of connective tissue that is penetrated by blood vessels (emissary veins) emerging through the skull, and beneath this connective tissue is the periosteum of the outer table of the skull. Injury to the vascular scalp can lead to profuse bleeding which, although can usually be stopped by local application of pressure, in some circumstances (e.g. acute alcohol intoxication) can lead to physiological shock and death. Bleeding scalp injuries can continue to ooze after death, particularly when the head is in a dependent position. The scalp is easily injured by blunt trauma as it can be crushed between the weapon and the underlying skull. Bruises of the scalp are associated with prominent oedema because this normal tissue response cannot spread and dissipate as easily as in other areas of the body. The easiest way to detect scalp injuries is by finger palpation, but shaving is often required for optimal evaluation, documentation and photography of injury in the deceased, and
■ Introduction ■ Head injuries ■ Neck injuries ■ Spinal injuries ■ Chest injuries ■ Abdomen ■ Further information sources
sometimes in the living. In the living a good history from the individual, and lighting, can localize any injury. It is surprisingly difficult to identify the site of profuse bleeding from the scalp in an individual with abundant head hair. In the living if there is evidence of stamping or implement assault it may also be necessary to shave the hair so that potential ‘patterned injury’ can be identified and recorded for overlay comparison. Lacerations of the scalp can usually be distinguished from incised wounds; careful examination often reveals crushed, abraded or macerated wound edges and tissue bridges in the wound depths (Figure 9.1). Occasionally such a distinction is more difficult, and it may be that the nature and properties of the scalp, its relative ‘thinness’ and tethering to the skull, contributes to the appearance of an incised wound following blunt impact. Tangential forces or glancing blows, either from an implement or from a rotating wheel (e.g. in a road traffic accident), may tear large flaps of tissue, exposing the underlying skull. If hair becomes entangled in rotating machinery, portions of the scalp may be avulsed. These are referred to as ‘scalping‘ injuries.
