ABSTRACT
This chapter presents the information necessary to detect early warning signs of pressure sores and to reliably identify persons most at risk of developing them. The human skin has a variety of colors and shows remarkable individual variations even within racial groups. The appearance of the skin is partly due to the reddish pigment in the blood of the superficial vessels. When enough pressure is applied to the skin of a white subject through a transparent surface, a sharply outlined spot that looks much whiter than the rest of the skin is immediately noticed at the pressure site. Blood supplying nutrients to the skin tissue is subject to the same local autoregulatory mechanism for blood flow as that found elsewhere in the body. Therefore, when the skin tissue is deprived of nutrients because of a completely blocked blood flow for some time, the skin blood flow becomes far greater than normal immediately after release of the pressure.
