A bruise is a mark on your skin caused by blood trapped under the surface. It happens when an injury crushes small blood vessels but does not break the skin. Those vessels break open and leak blood under the skin. Bruises are often painful and swollen. You can get skin, muscle, and bone bruises.
Black and blue marks are often associated with bruises. A bruise, or contusion, appears on the skin due to trauma. Examples of trauma are a cut or a blow to an area of the body. The injury causes tiny blood vessels called capillaries to burst. Blood gets trapped below the skin’s surface, which causes a bruise.
Bruises can occur at any age. Some bruises appear with very little pain, and you might not notice them. While bruises are common, it’s important to know your treatment options and whether your condition warrants emergency medical attention.