Wound is an injury to living tissue caused by a cut, blow, or other impact, typically one in which the skin is cut or broken.
Once wound occurs body tries to repair the defect and the process of wound healing is summation of a number of processes which follow injury including coagulation, inflammation, matrix synthesis and deposition, angiogenesis, fibroplasia, epithelialisation, contraction, remodelling and scar maturation
If the wound edges are apposed healing proceeds rapidly to closure and is known as healing by first intention or primary healing. When the wound edges are apart, rapid closure is not possible and body tries to fill the defect with help of granulation tissue and the process is known as healing by healing by second intention and it results in formation of scar tissue.
Tidy wounds are inflicted by sharp instruments and contain no devitalised tissue; such wounds can be closed primarily with the expectation of quiet primary healing.
Surgical incisions, wounds from cut glass or knife aer classified as tidy wounds. In these wounds , skin would be cut in a single and clean slash.
Tendons, arteries and nerves will commonly be injured in tidy wounds, but repair of these structures is usually possible.
Untidy wounds result from crushing, tearing, avulsion, vascular injury or burns, and contain devitalised tissue Wounds on the skin are irregular and multiple wounds may be present.
There may be associated skin loss and exposure of tendons, arteries and nerves. Such wounds must not be closed primarily and are often associated with problems during wound healing.
The correct management of untidy wounds is wound excision of all devitalised tissue to create a tidy wound [debridement]. The purpose is to convert a tidy wound into clean enough to let it heal by secondary intention.
Some wounds may require multiple sessions of debridement.
Bruise, Contusion and Hematoma
Bruise of contusion occurs due to blunt injury to the tissues. Bruises require no specific management. Time required for bruising to clear is extremely variable and in some individuals, discoloration may persist for months. Hematoma refers to localized collection of blood in the tissue. Initially it is fluid but then clots after some time. Over the period, it is liquefied and absorbed. Some hematomas are very large and may persist, requiring intervention.
Hematomas carry a danger of secondary infection.
Blunt injuries can also result in sat separation in subcutaneous tissue causing an indentation for prolonged period.
Puncture wounds and Bites
A puncture wound is an open injury in which foreign material and organisms are likely to be carried deeply into the underlying tissues. Common causes are standing on a nail or other sharp object.
On the surface, in cases of puncture wounds, there may not be much to see. An x-ray would detect any foreign body like metal fragments or glass.
Wound irrigation, antibiotic and tetanus prophylaxis is the usual treatment. If the foreign body is large, it is removed. Radio-opaque objects could be removed by aid of C-arm image intensifier.
Animal bites may result in small, sharp, incised wounds or in severe tissue crushing as in horse bites. There could be tissue avulsion or puncture wounds and teeth marks.
Human bites can result from act of biting or wound due to hitting the incisor teeth. The latter frequently presents with a puncture wound over the metacarpophalangeal joints.
Abrasion occurs due to shearing injury of skin in which the surface is rubbed off. Most are superficial and will heal by epithelialisation, but some may result in full-thickness skin loss. The treatment is by wound cleaning and antibiotics. Deep abrasions may need skin grafting.
A laceration or cut is the result of contact with a sharp object . The wound may be deep and underlying structures must be assessed in all lacerations. Lacerations are treated by wound cleaning and wound repair.
Traction and Avulslon
Avulsion injuries usually occur when hands or limbs are trapped in moving machinery, such as in rollers, producing a degloving injury. The injury is resulted by shearing forces that separate tissue planes, rupturing their vascular interconnections and causing tissue ischaemia.
Degloving is most frequently encountered between the subcutaneous fat and deep fascia. Both open and closed degloving injuries are known.
It could be limited or extensive, in a single or multiple tissue planes.
Degloving injury leads to risk of devascularisation of tissue and necrosis. Treatment involves debridement and removal of devitalized tissue and skin coverage procedures.
Crush injury is a variant of blunt injury where the force applied is so much that it disrupts the structural arrangement of the tissues, and are often accompanied by degloving and compartment syndrome.
A stab wound is the one where depth of the wound is much more than the external dimensions of the wound. These wounds may cause damage to internal organs.
Low-velocity injuries, such as from a hand gun, have smaller entry and larger exit wounds and cause damage along the tract of missile.
There would be severe tissue contamination from clothing, dirt or other foreign materials.
High-velocity injuries such as by modern assault rifles cause widespread tissue damage by explosion and decompression effect. The damage thus is farther from the tract of the missile.
Chronic Wounds may occur following trauma but there are other non-traumatic causes as well.
An ulcer is defined as breach in an epithelial surface. Chronic ulcers are wounds that fail to heal. They are characterized by fibrotic margin and a bed of granulation tissue which may include areas of slough or necrotic tissue.
Ulcers are common in leg and foot and occur due to vascular problems, poor innervations, poor wound healing, infection, mechanical irritation, ischaemia or other metabolic factors. Ulcers are common in diabetes and rheumatoid arthritis.
These are chronic wounds following tissue necrosis from pressure. They occur over bony prominences. Their pathogenesis is identical to compartment syndrome in that they arise where there is unrelieved pressure in the soft tissues overlying bone such that the external pressure exceeds capillary perfusion pressure and ischaemic necrosis occurs.