What Are Pressure Ulcers?

Understanding Your Body

Understanding Your Body provides easy-to-understand explanations of body systems and disease conditions. This material can be used for patient education, life sciences curriculum development, or to enhance public understanding of general health concepts. Permission for such use is not required, but citation as to source is requested. The information provided is derived from Consumer Versions of Clinical Practice Guidelines, sponsored by the Agency for Health Care Policy and Research, from 1992 to 1996.

A pressure ulcer is an injury usually caused by unrelieved pressure that damages the skin and underlying tissue. Pressure ulcers are also called decubitus ulcers or bed sores and range in severity from mild (minor skin reddening) to severe (deep craters down to muscle and bone).

Unrelieved pressure on the skin squeezes tiny blood vessels, which supply the skin with nutrients and oxygen. When skin is starved of nutrients and oxygen for too long, the tissue dies and a pressure ulcer forms. The affected area may feel warmer than surrounding tissue. Skin reddening that disappears after pressure is removed is normal and not a pressure ulcer.

Other factors cause pressure ulcers, too. If a person slides down in the bed or chair, blood vessels can stretch or bend and cause pressure ulcers. Even slight rubbing or friction on the skin may cause minor pressure ulcers.

The image 'Tissue Under Pressure' shows how Body Weight forces Bone against Muscle which in turn applies pressure to the underlying Tissues of the Skin.

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Current as of November 2007
Internet Citation: What Are Pressure Ulcers?: Understanding Your Body. November 2007. Agency for Healthcare Research and Quality, Rockville, MD. http://www.ahrq.gov/patients-consumers/prevention/understanding/bodysys/edbody6.html