<prompt> Feature that differentiates true from aificial bruiseRound shape, irregular marginsIrregular shape with regular marginsSwelling of surrounding areaErythema of surrounding areas  <response>: contusion: not well defined, diffuse, and irregular margins Aificial bruise: well defined with regular margins. Ref: FORENSIC MEDICINE AND TOXICOLOGY DR PC IGNATIUS THIRD EDITION PAGE 120 