A pressure injury (pressure ulcer) is caused by constant pressure to an area of skin. The pressure damages the skin and underlying tissue, creating an injury.

This often occurs when a person lies in bed or sits in a wheelchair for a long time. Pressure injuries usually form over bony areas such as your sit bones, hips, lower back, elbows, and heels. To prevent pressure injuries, you need to change positions often.

Severe pressure injuries are hard to treat and slow to heal. If they don't heal, they can lead to skin, blood, or bone infections.