What are Bruises? Bruises, also known as contusions, occur on a particular part of the body, when it has been struck and the connective tissue, as well as the muscle fibers that are present underneath the skin in that part, are crushed, even though the skin does not break. One of the main causes of bruising in people is that the blood leaks out from the ruptured capillaries, which are, the small blood vessels and gather under the skin...