37 muscles control the complex actions of the wrist and fingers. The wrist joint is formed by the lower, or distal ends of the two forearm bones, the radius and ulna, which articulate with several smaller bones known as carpals. When a person falls on their hand they risk fracturing any of these bones, particularly the lower end of the radius and the scaphoid, which is one of the larger carpal bones adjacent to the end of the radius.
The hand’s amazing dexterity owes a great deal to the multitude of small bones and joints within it. The radiocarpal joint is the primary wrist joint, where the radius meets two smaller bones, known as carpals, on the thumb side of the wrist. One of the bones, called the scaphoid, which is the larger of the two carpal bones, and the one most important in terms of its position in the wrist and the other, second bone, is the lunate. There are 6 additional carpal bones that don’t directly abut the radius.
The trapeziometacarpal joint forms between one of the carpals, the trapezoid and the base of the thumb. It’s a unique type of joint called a saddle joint, which has a perfectly concave end on one bone that fits over a convex end of the adjacent bone, allowing for the thumb’s circular range of motion. This circular range of motion, called opposition, is what enables the wrist to perform a great deal of manual activity. The metacarpals are long, thin bones of the hand that form joints with the carpal bones at the wrist and with the phalanges at the base of the fingers. The phalanges are the smaller bones of the fingers, each of which has 3 joints above the palm.
Retinacula are thick, fibrous bands of connective tissue that wrap around the wrist, forming tunnels that protect the tendons, blood vessels and nerves of the hand and arm. The flexor retinaculum forms the carpal tunnel, which runs along the underside of the wrist. It’s encloses, in a tight area, the flexor tendons and the median nerve. The flexor and extensor digitori are muscles of the forearm that flex and extend each of the five fingers.
Numerous ligaments in the hand and wrist provide stability to the joints. A variety of exercises help increase finger strength by working to condition the muscles and tendons that flex and extend the wrists and fingers. They also provide a fast, easy way to warm up hand and wrist areas before engaging in exercise.
Most wrist and hand injuries are avoidable with the use of protective gear. There are two commonplace varieties of wrist fractures. The distal radius fracture, which is the most common sports-related fracture, occurring just above the wrist and affecting the radius on the inner side. This type of fracture occurs when a person falls forward on an outstretched hand. Radius fractures cause pain and tenderness around the wrist and symptoms can be minor enough that the injury feels like a sprain rather than a fracture. A scaphoid fracture, however, is a break in the scaphoid bone, a kidney-bean shaped bone at the base of the thumb just above the wrist. Pain and swelling can be felt in the hollow side of the wrist just beneath the base of the thumb, an area referred to as the snuffbox because of the pocket it forms when your thumb is extended. Like fractures of the distal radius, this fracture also occurs commonly with falling on an outstretched hand. Because blood supply to this bone is poor, healing can be prolonged, or may not occur at all without medical intervention.
Suspected wrist fractures need to be treated by a physician because of potential complications to the nerves, tendons and blood vessels passing to the hand. Diagnosis can be difficult; small fractures will likely not show up on x-rays for a week or two.
Carpel tunnel syndrome is characterized by inflammation in the carpel tunnel causing compression of the median nerve, blood vessels and tendons that pass across the bottom of the wrist into the palm. The inflammation is triggered by overuse of the muscles and tendons crowded inside this narrow passageway. The pain is dull and achy or tingling; sometimes it manifests itself as numbness or weakness in the thumb, index finger or middle finger. To treat, ice the area and refrain from exacerbating activities. Wear a wrist support brace, a device that allows the irritated structures of the wrist to rest. After recovery, key prevention involves strengthening the muscles by implementing resistive exercises for the wrist and fingers. If symptoms persist and in severe cases of carpal tunnel syndrome surgery might be required.
Ulnar collateral ligament ruptures or sprains is a tear or rupture of the ulnar collateral ligament, the primary ligament connecting the metacarpal and phalangeal bones of the thumb. Often called skier’s thumb or gamekeeper’s thumb because it occurs when the thumb is forced down and backward, for example, when falling on an outstretched arm while gripping a ski pole. Pain and swelling are present in the web space of the thumb. With severe ruptures, the thumb joint will feel loose and unstable as a result of damage to the ligament. Mild injuries can be treated with cold therapy and immobilization, followed by range-of-motion exercises. Complete ruptures, which are noticeable by the high degree of weakness and instability felt in the thumb will require surgery.
Flexor tendon strains or ruptures are a common injury among rock climbers. The primary finger tendon running through the forearm becomes stretched, inflamed or torn through overuse. Strains of the tendon should be treated with cold therapy and rest from the offending activity. Ruptures are more serious and require medical attention.