Which term describes an injury where the skin surface is intact but underlying tissues are injured?

The term that describes an injury where the skin surface remains intact while the underlying tissues are injured is a contusion. A contusion occurs when small blood vessels are damaged, leading to localized bleeding beneath the skin, which causes discoloration and swelling without breaking the skin’s surface. This type of injury typically results from a direct impact or blunt force trauma.

In contrast, a hematoma refers to a collection of blood outside of blood vessels, generally formed when blood leaks into tissues or spaces due to a contusion or other injury. A laceration is defined as a tear or a cut in the skin, which disrupts the skin's surface. An incision refers specifically to a clean cut made by a sharp object, like a knife or scalpel, and also breaks the skin surface. Thus, the distinguishing feature of a contusion is that the skin remains intact while the tissues underneath are damaged, making this term the most accurate choice for the injury described in the question.