Ecchymosis is a large area of discoloration caused by extravasation of blood into the subcutaneous tissue. It is an objective physical finding that may provide valuable clues as to its possible etiology. Ecchymosis is associated with eponyms based on the physician who first described the physical findings, which can be divided into 4 anatomical categories: base of the skull, abdominal wall and retroperitoneum, groin and scrotum, and lower extremity. Classic external signs and eponyms associated with ecchymosis are reviewed. Knowledge of these signs on physical examination may prove to be a useful clue directing the examiner to consider potentially serious causes of disease.