Which of the following best defines 'contusion'?

A contusion is best defined as a bruise that occurs when small blood vessels are damaged or broken as a result of a blow to the skin. This leads to bleeding under the skin, which presents as discoloration, swelling, and tenderness in the affected area. The accumulation of blood in the tissues gives the contusion its characteristic appearance, often changing colors over time as the body reabsorbs the blood.

Understanding that a contusion involves blood pooling under the skin helps to distinguish it from other types of injuries. For example, cuts on the skin are classified as lacerations and involve the skin being broken, which is not the case with a contusion. Swelling of a joint typically indicates an inflammatory response or injury to the joint itself rather than a bruise. Scar tissue formation refers to the healing process that takes place after injuries, including cuts, but is unrelated to the bruising process defined by a contusion.