The use of photographs to record variation in bruising response in humans.

There is considerable value in developing tools capable of accurately and reliably determining when bruises were inflicted in humans. Previous work has focused on the visual changes observed in a bruise as the injury develops and heals. However, due to variables such as how and where on the body the bruise was inflicted, differing tissue compositions at the injured skin site between individuals and inter- and intra-observer variation; a technique sufficiently robust for use in a clinical or medicolegal setting has not yet been identified. In this study we present a series of photographs taken under controlled conditions illustrating standardised bruises induced on participants using a weight dropping mechanism. We show that variation in the appearance of bruises over time across individuals is large and, although photography may be a suitable technique for the recording of injuries, it is not sufficiently reliable for determining the age of a bruise.