Human bite wounds may not sound very dangerous, but they are. Human bite wounds contain very high concentrations of bacteria, so the risk of infection is high. Even though the wound may appear insignificant, an infection can lead to a severe joint infection. About one third of all hand infections result from human bite wounds. These infections can progress quickly and result in significant complications, so early treatment is necessary.

Bites can transmit the human immunodeficiency virus (HIV), as well as the hepatitis B virus and syphillis. Joint infections can lead to septic arthritis. Someone who has a human bite wound should get prompt first aid and see a doctor within 24 hours of the injury if the skin is broken.

Sometimes the wound is incurred directly (an actual bite). Other times, it is indirect (a clenched fist strikes a tooth, which breaks the skin on the hand). In a fight, a punch to the mouth can result in an indirect bite injury at the knuckle joint (MP or metacarpophalangeal joint), which can lead to a severe infection and possible destruction of the joint if it is not promptly treated.

Signs and Symptoms
In some cases, the bite will not break the skin but may cause damage to underlying tendons and joints. If the skin is broken, there is the additional possibility of infection as well as injury to joints, tendons and nerves. An injury to the top of the hand can result in significant swelling within hours.

Signs of an infection include:

• Warmth around the bite wound
• Swelling
• Pain
• A pus discharge

Signs of damage to tendons or nerves include:

• An inability to bend or straighten the finger
• A loss of sensation over the tip of the finger

First aid
Don’t put the bitten area in your mouth!

If there is no bleeding, wash the wound thoroughly. Use soap and water or an antiseptic such as hydrogen peroxide or alcohol. Apply an antibiotic ointment and cover with a non-stick bandage. Watch the area carefully to see if there are signs of damaged nerves or tendons. If you see any, seek medical help immediately.

If there is bleeding, apply direct pressure with a clean dry cloth. Elevate the area. Do not clean a wound that is actively bleeding. Cover the wound with a clean dressing and seek medical help. In these situations, early intervention (within 24 hours) is needed to prevent complications.

Medical assistance
Be sure to tell your doctor how you got the bite. Your physician will measure the wound, note its location, and check for signs of nerve or tendon damage. The doctor may examine your arm to see if there are signs of a spreading infection. You may need to get X-rays and a blood test.

You may also need to get a tetanus shot and a prescription for antibiotics. You may also have to return in a day or two so that the physician can confirm that an infection has not developed. If the tendons or nerves have been injured, you may need to see a specialist for additional treatment.

Have you ever been so frustrated that you wanted to slam your fist into a wall? If you do, you could break one of the bones in your hand (metacarpals). Fractures of the hand bones account for about one-third of all hand fractures. In fact, fractures of the fifth bone (the one that leads to your little finger) are commonly known as “boxer’s fractures.”

The hand bones can break near the knuckle, mid-bone, or near the wrist. Signs and symptoms of a broken bone include:

• Swelling
• Tenderness
• Deformity
• Inability to move the finger
• Shortened finger
• Depressed knuckle
• Finger crosses over its neighbor when you make a partial fist

Diagnosis and Treatment
Your physician will request X-rays to identify the fracture location and type. The physical examination may include some range of motion tests and an assessment of sensation in the fingers to ensure that there is no damage to the nerves.

Most of the time, the physician can realign the bones by manipulating them without surgery. Then, a cast, splint or fracture-brace is applied to immobilize the bones and hold them in place. The cast will probably extend from the fingertips down past the wrist almost to the elbow to ensure that the hand bones remain fixed in place.

Your physician will probably request a second set of X-rays about a week later to ensure that the bones remain in the proper position.

You will usually have to wear the cast for three to four weeks, but you can probably begin gentle hand exercises after three weeks. Afterwards, the finger may be slightly shorter, but this should not affect your ability to use your hand and fingers.

Surgical options
Some hand fractures, such as those that break through the skin or result from a crushing accident, require surgery to stabilize and align the bones. The orthopaedic surgeon implants wires, screws or plates in the hand to hold the fracture in place. If the bone rotates while healing, loss of function could result.

After the bone has healed, the surgeon may remove the implants, or they may be left in the hand. Research to develop implants that are resorbed into the body is ongoing. Your physician may ask you to return frequently for check-ups to ensure that the joint doesn’t tighten (contract) during healing. You may experience some joint stiffness in your hand because of the long immobilization period.

Your physician may prescribe exercises to help restore strength and range of motion or recommend that you see a physical therapist.

You might think a broken finger is a minor injury, but without proper treatment it can cause major problems. The bones in a normal hand line up precisely, letting you perform many specialized functions like grasping a pen or manipulating small objects in your palm. When you fracture a finger bone, it can put your whole hand out of alignment. Without treatment, your broken finger might stay stiff and painful.

Signs of a fractured finger

• Swelling
• Tenderness
• Inability to move it completely
• Deformity

Diagnosis

If you think you broke your finger, tell your doctor right away exactly what happened and when. You have three bones (phalanges) in each finger and two in each thumb. Your doctor must determine not only which bone fractured, but also how it broke: straight across, in a spiral, into several pieces, or shattered completely.

Your doctor may want to see how your fingers line up when you extend your hand or make a fist. Does any finger overlap its neighbor? Angle in the wrong direction? Look too short? Your doctor may X-ray both of your hands for comparison.

Treatment and rehabilitation

Your doctor will put your broken bone back into place, usually without surgery. Sometimes you need pins, screws or wire to hold it together, especially if you have a complicated injury. You’ll get a splint or cast to hold your finger straight and protect it from further injury while it heals. Sometimes your doctor may splint the fingers next to the fractured one for support.

Your doctor will tell you how long to wear the splint – usually about three weeks. Sometimes you may need more X-rays as you heal so your doctor can check your progress.

Begin using your hand again as soon as your doctor determines it is okay to move your finger. Doing simple rehabilitation exercises each day will help reduce the finger’s stiffness and swelling. You may be required to see a physical therapist to assist you in these exercises.

Tendons are tissues that connect muscles to bone so that joints can bend or straighten. The flexor muscles that move your fingers and thumb are located in your forearm, above your wrist. Long tendons extend from the flexor muscles through the wrist and attach to the small bones of your fingers and thumb.

Anatomy
Each finger has two tendons; the thumb has one tendon. The tendons run along the palm side of the fingers and are very close to the surface of the skin, particularly where the skin folds as you bend your fingers.

The longer tendon (flexor digitorum profundus or FDP) attaches to the last bone of the finger and bends the tip; the shorter tendon (flexor digitorum sublimis or FDS) bends the middle joint of the finger.

If you tear (rupture) or cut (sever) the tendon anywhere along its route, at the wrist, in the palm of the hand, or along the finger, you may be unable to bend your finger. If you injure the FDS tendon, you may still be able to bend the finger, but not completely, and bending the finger will be painful.

Tendons are stretched tightly as they connect the muscle to the bone. If the tendon tears, the end connected to the muscle will be pulled back in toward the palm. Because the tendon can’t heal unless the ends are touching, a severed tendon must be sewn back together again (a surgical repair).

Types of injuries
Most often the flexor tendons are damaged by a cut. Because the nerves to the fingers are also very close to the tendons, a cut may damage them as well, resulting in a feeling of numbness on one or both sides of the finger.

Athletic injuries are also common, usually in football, wrestling or rugby. One player grabs another’s jersey, and a finger(usually the ring finger)gets caught and pulled. This type of injury is so common, it even has a name: “jersey finger.” You can also strain or rupture the tendon while rock climbing.

People with rheumatoid arthritis may experience a spontaneous rupture of the flexor tendons. You may notice that the finger no longer bends, but cannot recall when you lost the ability to bend it.

Signs and symptoms

• An inability to bend one or more joints of the finger
• Pain when you bend your finger
• An open injury, such as a cut, on the palm side of the hand, particularly in the joint area where the skin folds as the finger bends
• Mild swelling over the joint closest to your fingertip
• Tenderness along the finger on the palm side of the hand

Diagnosing your injury
See your physician whenever you injure your fingers, especially if you “jam” the finger and notice that you cannot bend or straighten the tip. For immediate first aid, apply ice and compression to slow the flow of blood to the damaged site.

Your doctor will ask you to bend and straighten the fingers and may apply resistance to test the strength of the fingers. Your doctor may also test the sensation and blood flow to your fingers to see if any nerves or blood vessels were also injured.

You may need to get an X-ray to see if there is any damage to the bone; if you have an open wound, you may need a tetanus shot or antibiotics.

Treatment
Your doctor may first clean and treat any superficial wounds and put your hand in a splint. Flexor tendon injuries require surgical repair and it’s best to have the surgery as soon as possible after the injury. The hand surgeon will sew the tendon together using special stitches on both the inside and outside of the tendon.

However, it can take up to two months before the repair is healed and strong enough to use your hand without protection. It may take another month or so before you can use your hand with any force.

In the meantime, you will need to wear a splint and see a physical therapist. The therapist will give you special exercises to perform. Follow your doctor’s and your therapist’s instructions carefully to ensure the best possible result.

Even after surgery, you may experience some stiffness in your finger. However, it will be considerably less than if you did not have the surgery.