What does the term hematoma refer to?

The term hematoma refers specifically to a localized collection of blood outside of blood vessels, which can result from the rupturing of blood vessels due to injury or trauma. This accumulation of blood leads to swelling in the affected area, creating the characteristic lump associated with a hematoma.

Hematomas are typically tender and may change color as they heal, often transitioning from red to purple and yellow as the body reabsorbs the pooled blood. This definition aligns well with the correct choice, which highlights that a hematoma is essentially a swelling that contains blood.

Understanding this concept is crucial for recognizing how hematomas can manifest in various clinical scenarios, such as following surgical procedures or injury, and differentiating them from other conditions related to blood. The other concepts presented, such as blood clots, uncontrollable bleeding, and infections, refer to different medical phenomena that do not specifically define what a hematoma is.