The leg is purple, generally in about two weeks time to be able to fully recover, the reason why the leg in the case of bumps and other closed injuries resulting in bruising, is due to some superficial tissue capillary rupture, resulting in the formation of red blood cells seeping within the superficial tissue, after appropriate treatment or self-recovery, can be gradually absorbed. Of course, the prerequisite is not to have abnormal coagulation mechanism, if there is abnormal coagulation function, or even coagulation dysfunction, the recovery is very slow, and even easy to bleeding gradually aggravated. Only when treated to a normal state can recovery take place in normal time and the exudate in the superficial tissues be completely absorbed by the red blood cells.