What causes bedsores or pressure sores?

A: Without thinking about it or realizing it, many people shift in their chair during meetings, fiddle with the radio when driving, and turn a dozen times in their sleep.  Daily, people make hundreds of subtle postural adjustments that help stave off problems arising from inactivity, however, people immobilized by paralysis, injury or illness, are at risk of developing health problems, including bedsores.

If a person has been immobilized, bedsores can be caused by the following:

    •    Sustained pressure: When the skin and underlying tissues are trapped between bone and a surface, such as a wheelchair or bed, then the blood flow is restricted. This deprives tissue of oxygen and other nutrients, and irreversible damage and tissue death can occur. This tends to happen in areas that aren't well padded with muscle or fat and that lie just over a bone, such as the spine, tailbone (coccyx), shoulder blades, hips, heels and elbows.

    •    Friction: The key to preventing bedsores, or pressure sores, is frequent shifts in position. But, the friction that occurs when you simply turn from side to side can injure or damage the skin, which makes it more susceptible to pressure sores.

    •    Shear: This occurs when the skin moves in one direction, and the underlying bone moves in another. Sliding down in a bed or chair or raising the head of a bed more than 30 degrees is especially likely to cause shearing, which stretches and tears cell walls and tiny blood vessels. Areas that are especially affected include the tailbone, which is where skin is already thin and fragile.