Hematoma
![A hemotoma of the upper arm of an adult male caused by a punch.](/Images/godic/202501/31/Upper_Arm_Bruise5009.jpg")
A hematoma or haematoma is a localized collection of blood outside the blood vessels, usually in liquid form within the tissue. An ecchymosis, commonly (although erroneously) called a bruise, is a hematoma of the skin larger than 10mm.
It is not to be confused with hemangioma, which is an abnormal buildup of blood vessels in the skin or internal organs.