We bruise because a blow or trauma to the surface of the body causes capillaries or veins to rupture, creating a collection of blood under the skin, a contusion.
Bruising results from damage to small blood vessels that lie directly under the skin. The coloring of the bruise results from the damaged blood vessel breaking and bleeding.
Energy distribution. When the flesh receives trauma, the energy ripples through tissue and blood vessels causing them to rupture, leaking blood under the skin.
Bruises are actually very small pools of blood under the skin. Some of our smallest blood vessels are fragile, and break when we suffer a blow. They are quickly repaired, but the blood that escapes forms a bruise.
