Most commonly, hematomas are caused by an injury to the wall of a blood vessel, prompting blood to seep out of the blood vessel into the surrounding tissues. A hematoma can result from an injury to any type of blood vessel (artery, vein, or small capillary).

Are hematomas something to worry about?

A hematoma usually is not a cause for concern. It is not the same thing as a blood clot in a vein, and it does not cause blood clots.

Where do hematomas occur?

Hematomas may occur in solid organs like the liver, spleen, and kidney, or they may occur within the walls of the small intestine or colon. Hematomas may also form within the lining of the abdomen or behind in the space where the kidneys are located. Orthopedic injuries or broken bones may cause hematomas.