A bruise occurs when a force causes blood vessels to break. Blood leaks into areas under the skin, resulting in pain, swelling, and skin discoloration.
Update Date 4/11/2015
Updated by: Linda J. Vorvick, MD, Medical Director and Director of Didactic Curriculum, MEDEX Northwest Division of Physician Assistant Studies, Department of Family Medicine, UW Medicine, School of Medicine, University of Washington, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.