What are hematomas?

Hematomas are defined as localized collections of blood outside of blood vessels, typically resulting from a break in the wall of a blood vessel. They occur when blood leaks into surrounding tissues, often due to trauma. The most common visible manifestation of a hematoma is a bruise, which appears as a discolored area on the skin. This happens because the leaked blood is situated under the skin, leading to visible coloration and swelling in the affected area.

The other definitions provided do not accurately describe hematomas. Inflammatory skin conditions involve reactions of the skin that result in redness, swelling, or irritation, but do not specifically refer to blood accumulation. Scabs are protective crusts that form over wounds as part of the healing process but do not involve pooled blood in the way hematomas do. Lastly, types of skin cancer are characterized by abnormal growth of skin cells and are unrelated to blood accumulation and bruising. Thus, the correct identification of hematomas aligns with their definition as collections of blood under the skin.