Pressure ulcers used to be called bedsores. Pressure ulcers are caused by pressure or rubbing of weight-bearing parts of the body. Areas where bones are close to the skin are especially prone to such ulcers. Constant pressure on the skin squeezes the tiny blood vessels that 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.
Pressure ulcers appear over bony parts of the body where there is irritation or pressure.
A reddened or darkened area of skin appears and does not go away within 30 minutes after you change your position to put less pressure on the area. The skin opens up and may ooze or drain. The ulcer is completely through the skin and may start to involve underlying tissues. Some yellow tissue may be seen. A deep ulcer develops.