An injury is damage to your body. It is a general term that refers to harm caused by accidents, falls, hits, weapons, and more. In the U.S., millions of people injure themselves every year. These injuries range from minor to life-threatening. Injuries can happen at work or play, indoors or outdoors, driving a car, or walking across the street.

Wounds are injuries that break the skin or other body tissues. They include cuts, scrapes, scratches, and punctured skin. They often happen because of an accident, but surgery, sutures, and stitches also cause wounds. Minor wounds usually aren't serious, but it is important to clean them. Serious and infected wounds may require first aid followed by a visit to your doctor. You should also seek attention if the wound is deep, you cannot close it yourself, you cannot stop the bleeding or get the dirt out, or it does not heal.

Other common types of injuries include

• Animal bites
• Bruises
• Burns
• Dislocations
• Electrical injuries
• Fractures
• Sprains and strains

A bruise is a mark on your skin caused by blood trapped under the surface. It happens when an injury crushes small blood vessels but does not break the skin. Those vessels break open and leak blood under the skin.

Bruises are often painful and swollen. You can get skin, muscle and bone bruises. Bone bruises are the most serious.

It can take months for a bruise to fade, but most last about two weeks. They start off a reddish color, and then turn bluish-purple and greenish-yellow before returning to normal. To reduce bruising, ice the injured area and elevate it above your heart. See your health care provider if you seem to bruise for no reason, or if the bruise appears to be infected.

As parents, we want to keep our children safe from harm. Take steps to keep your children safe:

• Install the right child safety seat in your car
• Teach children how to cross the street safely
• Make sure they wear the right gear and equipment for sports
• Install and test smoke alarms
• Store medicines, cleaners and other dangerous substances in locked cabinets
• Babyproof your home
• Don't leave small children unattended

When you come in direct contact with electricity, it can pass through your body and cause injuries. These electrical injuries can be external or internal. You may have one or both types. External injuries are skin burns. Internal injuries include damage to your organs, bones, muscles, and nerves. You could also have abnormal heart rhythms and sudden cardiac arrest (SCA).

How bad your injuries are depends on how strong the electric current was, what type of current it was, how it moved through your body, and how long you were exposed. Other factors include how healthy you are, and how quickly you get treatment.

Causes of electrical injuries include:

• Lightning strikes
• Faulty electrical appliances
• Work-related exposures
• Contact with household wiring or power lines
• Accidents in small children, when they bite or suck on electrical cords, or stick objects in outlets

If you get an electrical injury, you should see a doctor. You may have internal damage and not realize it.

Falls can be dangerous at any age. Babies and young children can get hurt falling off furniture or down the stairs. Older children may fall off playground equipment. For elderly people, falls can be especially serious. They are at higher risk of falling. They are also more likely to break a bone when they fall, especially if they have osteoporosis. A broken bone, especially when it is a hip, may even lead to disability and a loss of independence for the elderly.

Some common causes of falls include

• Balance problems
• Some medicines, which can make you feel dizzy, confused, or slow
• Vision problems
• Alcohol, which can affect your balance and reflexes
• Muscle weakness, especially in your legs, which can make it harder for you to get up from a chair or keep your balance when walking on an uneven surface.
• Certain illnesses, such as low blood pressure, diabetes, and neuropathy
• Slow reflexes, which make it hard to keep your balance or move out of the way of a hazard
• Tripping or slipping due to loss of footing or traction

At any age, people can make changes to lower their risk of falling. It important to take care of your health, including getting regular eye exams. Regular exercise may lower your risk of falls by strengthening your muscles, improving your balance, and keeping your bones strong. And you can look for ways to make your house safer. For example, you can get rid of tripping hazards and make sure that you have rails on the stairs and in the bath. To reduce the chances of breaking a bone if you do fall, make sure that you get enough calcium and vitamin D.

Accidents happen. Someone chokes on an ice cube or gets stung by a bee. It is important to know when to call 9-1-1 -- it is for life-threatening emergencies. While waiting for help to arrive, you may be able to save someone's life. Cardiopulmonary resuscitation (CPR) is for people whose hearts or breathing has stopped and the Heimlich maneuver is for people who are choking.

You can also learn to handle common injuries and wounds. Cuts and scrapes, for example, should be rinsed with cool water. To stop bleeding, apply firm but gentle pressure, using gauze. If blood soaks through, add more gauze, keeping the first layer in place. Continue to apply pressure.

It is important to have a first aid kit available. Keep one at home and one in your car. It should include a first-aid guide. Read the guide to learn how to use the items, so you are ready in case an emergency happens.

If you've ever gotten a splinter or had sand in your eye, you've had experience with a foreign body. A foreign body is something that is stuck inside you but isn't supposed to be there. You may inhale or swallow a foreign body, or you may get one from an injury to almost any part of your body. Foreign bodies are more common in small children, who sometimes stick things in their mouths, ears, and noses.

Some foreign bodies, like a small splinter, do not cause serious harm. Inhaled or swallowed foreign bodies may cause choking or bowel obstruction and may require medical care.

You can't remove all the safety hazards from your life, but you can reduce them. To avoid many major hazards and prepare for emergencies

• Keep emergency phone numbers by your telephones
• Make a first aid kit for your home
• Make a family emergency plan
• Install and maintain smoke alarms and carbon monoxide detectors
• Keep guns unloaded and locked up. Lock up the ammunition separately.
• Follow the directions carefully when using tools or equipment

Young children are especially at risk. Supervision is the best way to keep them safe. Childproofing the house can also help.

A scar is a permanent patch of skin that grows over a wound. It forms when your body heals itself after a cut, scrape, burn, or sore. You can also get scars from surgery that cuts through the skin, infections like chickenpox, or skin conditions like acne. Scars are often thicker, as well as pinker, redder, or shinier, than the rest of your skin.

How your scar looks depends on

• How big and deep your wound is
• Where it is
• How long it takes to heal
• Your age
• Your inherited tendency to scar

Scars usually fade over time but never go away completely. If the way a scar looks bothers you, various treatments might minimize it. These include surgical revision, dermabrasion, laser treatments, injections, chemical peels, and creams.

There are many reasons to have surgery. Some operations can relieve or prevent pain. Others can reduce a symptom of a problem or improve some body function. Some surgeries are done to find a problem. For example, a surgeon may do a biopsy, which involves removing a piece of tissue to examine under a microscope. Some surgeries, like heart surgery, can save your life.

Some operations that once needed large incisions (cuts in the body) can now be done using much smaller cuts. This is called laparoscopic surgery. Surgeons insert a thin tube with a camera to see, and use small tools to do the surgery.

After surgery there can be a risk of complications, including infection, too much bleeding, reaction to anesthesia, or accidental injury. There is almost always some pain with surgery.

Lacerations are a pattern of injury in which skin and underlying tissues are cut or torn. Healthcare providers encounter lacerations regularly. It was reported in 2005 that nearly 12% of all ER visits, or 13.8 million visits occurred for laceration care. Lacerations can be managed in the outpatient setting as well, depending on the location and severity of the injury.

The clinical presentation of lacerations can be highly variable based on location, depth, width, and length. Due to this highly variable presentation, the healthcare team must have a strong understanding of the critical history and physical exam items each laceration requires.

Indications

To best assess the future care requirements of any laceration, the healthcare team must first review the patient's history as well as do a complete physical examination of the wound and nearby structures.

Pertinent history items include:

• Time of initial injury

• Location of laceration and extremity injuries have an increased risk of infection.

• Measurements of laceration, including length, width, and depth. As the depth and width of injuries increase, the risk of infection increases.

• Mechanisms of injury, such as crush, sharp object, and shear from fall. Crush injuries with localized tissue injury have an increased risk of infection and scarring.

• Age, because at the extremes of age, there is a risk of poor healing.

• Past medical history, specifically any history of diabetes mellitus, chronic renal failure, obesity, malnutrition, or any use of immunosuppression drugs such as chemotherapy medications.

• Allergies, specifically to latex, anesthetics, or antibiotics.

• Immunization status, note the patient's tetanus vaccine history. Current guidelines for tetanus are:
  • Adults with greater than or equal to three previous tetanus doses:

    • Clean wounds: Tdap (tetanus, reduced diphtheria, pertussis) or Td (tetanus, reduced diphtheria) only if it has been over 10 years since their last vaccination.

    • Dirty/complex wounds: Tdap or Td if more than 5 years since their last vaccination.

  • Adults with under 3 previous tetanus doses:

    • All wounds: Tdap or Td required; if dirty/complex, they will also require immunoglobulin treatment.

  • Children:

    • Under 7 years old: DTaP (diphtheria, tetanus, pertussis) vaccine is the recommendation; if pertussis is contraindicated, give DT (diphtheria, tetanus) vaccine.

    • 7 to 9 years old: Td vaccine recommended.

    • Over 10 years old: Tdap is preferred in patients who have never received it and have no contraindications; if age or contraindications exist, use the Td vaccine.

Keys to a good physical exam of lacerations:

• Ensure appropriate lighting, gauze, and rinse materials are easily accessible before beginning the exam.

• Establish hemostasis: Hemostasis should be established to allow for visualization of underlying structures and foreign objects, utilizing direct pressure.

• Detailed neurologic exam: The clinician should perform a complete sensation exam at and below the level of injury before the use of any anesthesia to assess for any nerve injury. A quick method to evaluate for nerve injury is two-point discrimination using a standard paper clip, always comparing to the patient's noninjured side.

• Detailed musculoskeletal exam: Examine any joints involved in the laceration for injury, along with an active and passive range of motion exam above and below the joint to assess for tendon injury.

• Detailed Vascular exam: Assess capillary refill in the distal to the wound if on the extremities, and compare to noninjured side always. If accessible, Doppler ultrasound can be utilized to assess underlying vascular integrity, following from above the laceration to below.

• Foreign bodies, if observed, should be removed, as they can increase the patient's risk of infection or poor wound healing. If there is any concern about retained foreign bodies, imaging should be obtained.

Wild animals usually avoid people. They might attack, however, if they feel threatened, are sick, or are protecting their young or territory. Attacks by pets are more common. Animal bites rarely are life-threatening, but if they become infected, you can develop serious medical problems.

To prevent animal bites and complications from bites

• Never pet, handle, or feed unknown animals
• Leave snakes alone
• Watch your children closely around animals
• Vaccinate your cats, ferrets, and dogs against rabies
• Spay or neuter your dog to make it less aggressive
• Get a tetanus booster if you have not had one recently
• Wear boots and long pants when you are in areas with venomous snakes

If an animal bites you, clean the wound with soap and water as soon as possible. Get medical attention if necessary.

A burn is damage to your body's tissues caused by heat, chemicals, electricity, sunlight, or radiation. Scalds from hot liquids and steam, building fires and flammable liquids and gases are the most common causes of burns. Another kind is an inhalation injury, caused by breathing smoke.

There are three types of burns:

• First-degree burns damage only the outer layer of skin
• Second-degree burns damage the outer layer and the layer underneath
• Third-degree burns damage or destroy the deepest layer of skin and tissues underneath

Burns can cause swelling, blistering, scarring and, in serious cases, shock, and even death. They also can lead to infections because they damage your skin's protective barrier. Treatment for burns depends on the cause of the burn, how deep it is, and how much of the body it covers. Antibiotic creams can prevent or treat infections. For more serious burns, treatment may be needed to clean the wound, replace the skin, and make sure the patient has enough fluids and nutrition.

A burn is tissue damage caused by heat, chemicals, electricity, sunlight, or nuclear radiation. The most common burns are those caused by hot liquid or steam, building fires, and flammable liquids and gases.

Burns are defined by how deep they are and how large an area they cover. A large burn injury is likely to include burned areas of different depths.

Deep burns heal more slowly, are more difficult to treat, and are more prone to complications such as infections and scarring. Very deep burns are the most life-threatening of all and may require amputation. Types of burns include:

• First-degree burns damage the outer layer (epidermis) of the skin. These burns usually heal on their own within a week. A common example is a sunburn.
• Second-degree burns damage not only the outer layer but also the layer beneath it (dermis). These burns might need a skin graft—natural or artificial skin to cover and protect the body while it heals—and they may leave a scar.
• Third-degree burns damage or completely destroy both layers of skin including hair follicles and sweat glands and damage underlying tissues. These burns always require skin grafts.
• Fourth degree burns extend into fat, fifth degree burns into muscle, and sixth degree burns to bone.

Cross-section of skin anatomy shows layers and different tissue types. Credit: NIGMS.

Severe burns cause serious, body-wide problems. At the root of most of these problems is the body’s explosive inflammatory response.

A normal inflammatory response protects the body from invaders, such as bacteria, viruses, fungi, cancerous cells, toxins, and foreign materials. It activates in response to infection, injury, or other threat. It is designed to destroy the cause of the problem, contain the damage, and clean up the mess left by dead cells and other debris. But when faced with large or deep burns, it can overreact, often making the injury more severe and harming the heart, lungs, blood vessels, kidneys, and other organ systems.

During this inflammatory response, there is fluid loss that can cause a sharp and potentially deadly drop in blood pressure known as shock. Fluid can also become trapped inside the body, leading to swelling known as edema. If tissues and organs do not receive enough oxygen because of shock, edema, or something else, they suffer damage and can fail. The lungs, heart, brain, and kidneys are particularly susceptible.

Infection is also a major concern. Burns damage the skin’s protective barrier, meaning bacteria and other foreign invaders can sneak in. Burns also weaken the immune system, so the body is less able to fight off threats. Infections can take hold not only in the injured area, but also in organs such as the lungs (pneumonia) and bloodstream (sepsis), where they are potentially lethal.

Dislocations are joint injuries that force the ends of your bones out of position. The cause is often a fall or a blow, sometimes from playing a contact sport. You can dislocate your ankles, knees, shoulders, hips, elbows and jaw. You can also dislocate your finger and toe joints. Dislocated joints often are swollen, very painful and visibly out of place. You may not be able to move it.

A dislocated joint is an emergency. If you have one, seek medical attention. Treatment depends on which joint you dislocate and the severity of the injury. It might include manipulations to reposition your bones, medicine, a splint or sling, and rehabilitation. When properly repositioned, a joint will usually function and move normally again in a few weeks. Once you dislocate a shoulder or kneecap, you are more likely to dislocate it again. Wearing protective gear during sports may help prevent dislocations.

Displacement of bones from their normal positions at a joint.

A fracture is a break, usually in a bone. If the broken bone punctures the skin, it is called an open or compound fracture. Fractures commonly happen because of car accidents, falls, or sports injuries. Other causes are low bone density and osteoporosis, which cause weakening of the bones. Overuse can cause stress fractures, which are very small cracks in the bone.

Symptoms of a fracture are

• Intense pain
• Deformity - the limb looks out of place
• Swelling, bruising, or tenderness around the injury
• Numbness and tingling
• Problems moving a limb

You need to get medical care right away for any fracture. An x-ray can tell if your bone is broken. You may need to wear a cast or splint. Sometimes you need surgery to put in plates, pins or screws to keep the bone in place.