Bruise (Contusion of the Skin)
Bruises (contusions) occur when small blood vessels under the skin tear or rupture, most often from a twist, bump, or fall. Blood leaks into tissues under the skin and causes a black-and-blue color that often turns purple, red, yellow, and green as the bruise heals.
eMedicineHealth Medical Reference from Healthwise
To learn more visit Healthwise.org