The hand is made up of many bones. At the base of the hand, there are two rows of small bones, with four bones in each row. These bones are the carpals. The carpals on the bottom row join with the bones of the lower arm–the radius and the ulna–to form the wrist joint. The carpals on the top row at the base of the hand connect to the five bones of the palm, called metacarpals. The metacarpals connect to the bones of the fingers and the thumb. Each finger is made up of three bones; and the thumb is made up of two. These bones are the phalanges.

Multiple small joints and many different types of tissue work together to allow the hand to perform its specialized functions, including grasping and manipulating objects.

Common problems of the hand are arthritis, carpal tunnel syndrome, fractures, sprains, tendonitis of the wrist, ganglion cysts, trigger finger, and Dupuytren's contracture.

Osteoarthritis–The most common form of arthritis, it develops with age. Over time, the thin covering on the ends of bones (cartilage) becomes worn and frayed, resulting in pain, stiffness, swelling, and weakness.

Rheumatoid arthritis–A systemic disease that occurs when the body's immune system turns against itself, producing substances that attack and inflame the joints. The most common symptoms are pain, swelling, stiffness, and decreased grip strength. The disease often starts in the smaller joints and usually affects the same joint on both sides of the body.

Carpal tunnel syndrome–A condition caused by pressure on the median nerve, which enters the hand through the confined space of the carpal tunnel. Symptoms include numbness; tingling; pain, sometimes up to the shoulder; clumsiness in handling objects; and a feeling like electric shock. Symptoms usually begin gradually but may become constant over time.

Fracture–Symptoms of a broken finger, thumb, or wrist include pain, swelling, tenderness, and deformity. Breaks can result from falls; sports, automobile, and other accidents; or twisting and crushing injuries.

Sprain–An injury in which a ligament is stretched or torn. Tears may be partial or complete. Thumb and wrist sprains generally occur from falls where the arm was extended. Symptoms include bruising, tenderness, pain, and swelling.

Tendonitis of the wrist–Irritation and swelling of the sheath that surrounds the tendons in the thumb-side of the wrist. Symptoms include pain when forming a fist, turning the wrist, or grasping or gripping an object; stiffness in the thumb and wrist; and numbness on the back of the thumb and index finger.

Ganglion cyst–A non-cancerous, fluid-filled mass on the hand arising from irritated or inflamed ligaments, joint linings, or tendon sheaths. Most commonly found on the back of the wrist, the cyst may or may not be painful.

Trigger finger–A condition that causes pain and catching in a finger. Symptoms generally start without any injury. In severe cases, the affected finger may become stuck in a bent position.

Dupuytren's contracture–A hereditary thickening of the fascia (tough tissue that lies just below the skin) on the palm. The condition may range from small lumps or bands, to very thick bands. Symptoms usually occur gradually. The condition may eventually pull the fingers into the palm.

Other problems of the hand include ulnar tunnel syndrome, boutonniere deformity, flexor tendon injuries, Kienböck's disease, mallet finger, and reflex sympathetic dystrophy.

Ulnar tunnel syndrome–A condition caused by pressure on the ulnar nerve. Symptoms develop gradually and include pain, weakness, and numbness or tingling in the little finger and the outside of the ring finger.

Boutonniere deformity–An injury to the tendons that usually prevents the fingers from fully straightening. Often caused by a forceful blow to a bent finger. Symptoms include swelling and pain.

Flexor tendon injury–Occurs when a tendon in the finger is cut, stretched, or ruptured. Symptoms include an inability to bend one or more joints in the finger, pain when the finger is bent, mild swelling over the joint closest to the fingertip, and tenderness along the finger on the palm side of the hand.

Kienböck's disease–A disease in which the blood supply to the lunate (one of the small bones of the hand near the wrist) is interrupted. Symptoms include a painful and sometimes swollen wrist, stiffness and limited range of motion in the affected wrist, decreased grip strength in the hand, and tenderness directly over the bone (on the top of the hand at about the middle of the wrist).

Mallet finger–A deformity caused by damage to the extensor tendon. Damage often results from something striking the tip of the finger or thumb. Symptoms include an inability to straighten the finger or thumb, pain, swelling, and bruising.

Reflex sympathetic dystrophy–A condition caused by a disturbance in the sympathetic nervous system. May result from infection, cancer, a neck disorder, stroke, heart attack, or pressure on a nerve. Symptoms include burning pain, stiffness, swelling, and discoloration in the hand.

Source: American Association of Orthopaedic Surgeons