Which of the following describes an open wound?

An open wound is characterized by a break in the skin, which allows external elements such as bacteria, dirt, and other contaminants to enter the body. This type of wound may involve varying degrees of damage to the underlying tissues and can lead to additional complications such as infection. Open wounds require prompt and proper treatment to minimize the risk of complications, which is critical for effective healing.

The other options describe different types of injuries. Internal injuries refer to damage that occurs within the body without any external signs on the skin. A bruise under the skin, known as a contusion, occurs when blood vessels break due to impact, leaking blood into the surrounding tissue, but does not involve a break in the skin itself. Closed tissue damage implies that the skin is intact but there may be injuries to the underlying tissues, such as sprains or strains, which also do not meet the definition of an open wound.