What type of injury is best described by a clean edge and no bruising?

An injury characterized by a clean edge and no bruising is best identified as an incision. Incisions are typically produced by sharp objects, such as knives or scalpels, and they result in clean, well-defined wound margins. This type of injury does not usually lead to bruising because the cutting action primarily affects the skin and underlying tissues without damaging the small blood vessels deeply, which is necessary for bruising to occur.

In contrast, stab wounds are often deeper than incisions and can also have irregular edges. They may produce bruising depending on the angle and force of the penetration. Lacerations are tears or splits in the skin that can have jagged edges, resulting from blunt force trauma, and often involve bruising due to the tearing of underlying blood vessels. Contusions, or bruises, are not cuts or wounds but rather injuries to blood vessels, causing bleeding under the skin without breaking the surface, which is not consistent with the description of a clean-edged injury.

Thus, the clean-cut nature of an incision aligns perfectly with the details provided in the question.