By definition, a wound is a physical injury that results in an opening or break of the skin.

Types:
There are several types of wounds, including surgical, traumatic, and chronic wounds. Traumatic wounds may be caused by mechanical, traumatic or thermal injury, including contusions, abrasions, punctures, fractures, burns, and frostbite. The surgical wound is usually clean and easiest to heal. By definition, chronic wounds may be more difficult to heal, and include pressure sores and diabetic ulcers.

Generally, wounds can be further classified into 2 categories: partial and full thickness. Partial thickness wounds present with damage to the epidermal and dermal tissues, including flame burns, scalds, and blisters, usually being painful to the touch. Full thickness wounds present with damage to epidermal, dermal, or subcutaneous tissues, including flame burns, boiling liquids and chemical burns, usually without pain being evident.

The most common type of wound is a traumatic wound. Traumatic wounds are categorized into several types: (1) abrasion - exists when the surface of the skin or a mucous membrane is scraped away, (2) contusion - an injury where the surface of the skin is not broken, but underlying or internal tissues are damaged, usually resulting from a sharp blow to the body and frequently producing a discoloration or bruising of the skin surface, (3) incision - a traumatic wound made with a sharp instrument that produces a clean cut, such as a scalpel, (4) tunneled wound - presents with a passageway under the surface of the skin that is generally open at the skin level, with most of the tunneling not seen, (5) laceration - the skin is irregularly torn and a penetration wound results from events like a stab or gunshot, (6) bites - abrasions and/or contusions caused by the entrance and crushing of teeth, usually in animals, humans, or insects, (7) cuts - classified as traumatic wounds where there is only a minor break in the integrity of the skin, and (8) thermal wounds - include heat injuries such as burns, sunburns, and electric injuries.

Surgical wounds result from the trauma induced by surgery. Surgical wounds include: (1) post-surgical incisions, including dental extraction, (2) suture site wounds, (3) donor site wounds such as in blood donation, (4) IV site wounds, (5) skin graft wounds, (6) periostomy skin wounds, and (7) peritracheotomy wounds.

The most difficult wounds to treat are the chronic, non-healing wounds. These include: diabetic wounds, arterial ulcers, venous ulcers, and pressure ulcers.

Repair of the Wound:
The process of repair and regeneration following injury represents one of the most fundamental defense mechanisms of an organism against the environment. Wound healing in individuals generally occurs over a reasonable length of time. However, there are reasons that wounds may not heal appropriately, such as in impaired immunity, diseases such as diabetes and CVD, immobility, poor nutrition, and the like. Intervention is necessary in these individuals. Even with minor injuries such as cuts, wounds in impaired individuals may readily develop into very traumatic injuries requiring medication, hospitalization, and even surgery. In general, if a wound does not heal within a month, medical intervention is necessary.

Immediately after injury, the wound fills with blood and a clot forms. The clot contains a threadlike protein called fibrin, which binds the edges of the wound together and stops any bleeding. If tissues are damaged, a cascade of cellular events is initiated to prepare the injured area for the deposition of collagen, which ultimately will replace damaged mesenchymal tissues. Wound healing occurs in several stages.

1. Inflammation: A wound initiates a natural inflammatory response with heat, redness, pain, swelling, and impaired function of the involved body tissues. Vasoco