The appearance of bruises on the body come from a shock or trauma more or less severe. In medical jargon, these are called contusions. The bruises are therefore in the form of blue skin patches, but sometimes appear in other colors in the course of their progression, purple, black, or yellow. They are the result of a break in the small blood vessels, responsible for the presence of blood in the cellular tissue under the skin. Bruises usually disappear spontaneously after a few days. The elderly are more prone to bruises because their delicate skin is more likely to be affected.