A wound appearing as superficial can result in serious complications if treated wrong.

Although first aid for lacerations and bruises is well-known and straightforward and healing usually occurs without complications, some can result in disability. Special care is needed when dealing with lacerations on or near joints, wounds from animal or human bites, punctures, and wounds involving underlying nerves or blood vessels. In bruises (contusions), the main danger is not infection but swelling which can result in damage to the underlying soft tissues.Joint wounds

Knee joints pose special problems and should be irrigated with soap and water thoroughly to remove all foreign material. Lacerations around the knuckles are also prone to complications.

Human bites

With more than 40 species of aerobic and anaerobic bacteria in the mouth - and more than 100 million organisms per milliliter of saliva - the chances of serious infection and disability are extremely high. Complications ranging from permanent joint stiffness to amputation may occur in more than 50 percent of cases.

Thorough irrigation with soap and water is essential. Dressings should be changed daily, and this also involves inspecting the wound for localized infection.

Animal bites

With some 2 million dog bites each year in the United States comes the statistic that about 1 percent of emergency department admissions come from dog bites. Care of dog and other animal bites is similar to care of human bites with the possible need for rabies innoculations as an additional consideration. Also, dog bite injuries may consist of tissue avulsion rather than lacerations.

Like human bites, dog bites require extensive irrigation with soap and water.

Gunshot wounds

A gunshot wound's severity depends largely on the caliber and speed of the bullet. Small caliber, low-velocity bullets traveling under 1,000 feet per second tend to produce entrance and exit wounds of about equal size, and little damage along the bullet tract.

Military or sporting rifles with bullet velocities of 3,000 feet per second or more may also produce small entrance wounds, but internal damage will be much greater. The high speed of the bullet produces a vapor-filled cavity around the bullet tract that may be many times the diameter of the bullet itself.

Shotgun wounds are similar to high-velocity bullet wounds and require much the same management. The numerous pellets blow tissue away and carry dirt into the wounds.

Bruises

Swelling that accompanies injuries can affect circulation, restrict soft-tissue motion and stiffen the joints. Hand and wrist fractures can have swelling (edema) that is more destructive than the bone injury itself.

For example, one case involving a fractured wrist involved a young man who complained about painful swelling and stiffness after a cast was applied. When the cast was removed after eight weeks, he was unable to move his fingers. Two years later, he had lost all motion of the fingers and had a substantial loss of hand use.

Initially, a hand should be wrapped in a soft compressive "boxing glove" dressing, kept immobilized, splinted and comfortably elevated for two or three days until swelling subsides.

Complications arise not only in hands, but ankles as well, when bruises and sprains happen.

-Alton Thygerson is a professor of health sciences at Brigham Young University.