What is the term for the escape of blood from a blood vessel into surrounding tissue?

The term for the escape of blood from a blood vessel into surrounding tissue is "extravasation." This process typically occurs when blood vessels are damaged, allowing blood to leak out into the extracellular space. Extravasation can result from various causes, including trauma, surgical procedures, or inflammatory processes, and can lead to swelling and discoloration in the affected area.

While hematoma refers specifically to a localized collection of blood outside of blood vessels, usually in a confined space or cavity, and hemorrhage describes the broader phenomenon of blood loss, extravasation focuses on the process of blood moving into surrounding tissue. Ecchymosis, on the other hand, denotes a type of bruise where blood has leaked into the skin or mucous membrane, but this is a consequence of extravasation rather than the term for the process itself. The distinctive aspect of extravasation is that it emphasizes the movement of blood into tissue rather than just simply stating it has occurred.