A contained collection of blood that can be quite large is called a

• A. Hematoma
• B. Contusion
• C. Epistaxis
• D. Avulsion

Answer: (A)

A contained collection of blood outside a vessel is a hematoma. It forms when a blood vessel ruptures and the blood pools in surrounding tissue or a potential space, bounded by tissue so it doesn’t flow away freely. This can create a noticeable lump that may enlarge as bleeding continues or as the body resorbs the blood.

By contrast, a contusion is a bruise from capillary damage under the skin that causes discoloration rather than a distinct blood pool. Epistaxis is a nosebleed, a bleeding source from the nasal mucosa. An avulsion is when tissue is torn away, often with a flap of skin or other structures. So the description of a contained blood collection most accurately matches a hematoma.