If the skin or mucous membrane is penetrated, an open soft tissue injury exists.
The injury can be an abrasion, laceration, avulsion, or puncture.
An abrasion is an injury caused by scraping the skin against a rough surface. The damage is usually confined to the epidermis and part of the dermis.
A laceration is a cut or tear in the skin. The wound may extend through the subcutaneous tissue and into the muscle tissues. Major blood vessels and nerves may also be involved.
An avulsion is a tearing away of tissue. The separated part usually contains epidermis, dermis and subcutaneous tissue layers.
A puncture is caused by an object such as a splinter, bullet, knife, or shrapnel penetrating the flesh. If the object goes through the body part and exits on the opposite side, the wound is called a perforated wound. If the object remains in the wound and protrudes above the skin, the object is said to be impaled. Even if the wound appears to be small and the bleeding does not appear to be severe, the object may still have caused significant internal damage.
An amputation is the complete removal of tissue from the body. It may start as an avulsion type wound with a tearing away of the tissue, but once it is completely severed, the part is considered amputated. An amputation can also be complete separation of a limb from the body.