Bruise

A bruise, also called a contusion  or an ecchymosis .happens when a part of the body is struck and the muscle fibers and connective tissue underneath are crushed but the skin doesn't break. When this occurs, blood from the ruptured capillaries  near the skin's surface escapes by leaking out under the skin. With no place to go, the blood gets trapped, forming a red or purplish mark that's tender when you touch  .

Bruises can happen for many reasons, but most are the result of bumping and banging into things — or having things bump and bang into you. Fortunately, as anyone who's ever sported a shiner knows, the mark isn't permanent