Tuesday, August 6, 2013

My Wrist Hurts - What Can Be Done to Help Me?


The wrist is a complex joint. It consists of eight small bones - called "carpal bones" -arranged in two rows of four bones each. These two rows of bones lie between the bones of the forearm and the bones of the hand.

The row of wrist bones closest to the forearm consists of the scaphoid, lunate, triquetrium, and pisiform.

The distal row- the row closest to the hand consists of the trapezium, trapezoid, capitate, and hamate.

The carpal bones are connected to each other by ligaments. In addition, various tendons attach muscles to bones.

The structure of the wrist allows range of motion in multiple directions including bending and extending, side-to-side, and rotation.

A variety of important structures pass from the arm to the hand. As a result, disorders of the wrist can impact functioning in the hand.

Because of the complex nature of the wrist, there are multiple problems that can develop and lead to wrist pain.

While the diagnosis can be suspected on clinical grounds, generally imaging procedures such as magnetic resonance imaging are required for confirmation.

Trauma is probably the most common cause of wrist pain. This may occur as the result of a fall. A fall on an outstretched hand can lead to fracture of the distal radius, the larger of the two forearm bones. This is particularly common in older individuals who have osteoporosis.

Fracture can also cause fracture and loss of blood supply to the wrist bones. The latter problem causes a condition called Kienbock's disease, or avascular necrosis of the scaphoid wrist bone.

Trauma can also cause ligament tears. One of the common ligament tears occurs in the ligament between the scaphoid and the lunate. This causes pain the central part of the wrist and is aggravated by motion.

The other ligament which can also be torn is the triangular fibrocartilage complex. This ligament actually functions as a cushion at the end of the ulna bone in the forearm (the side of the wrist that the fifth finger is on.) With ligament tears, pain can be accompanied by a clicking or clunking sound.

Because numerous tendons run along the top and the bottom of the wrist, tendonitis is a common wrist affliction. Along the radial (thumb) side of the wrist, inflammation of the tendons leads to a condition called DeQuervain's tendonitis. When the hand is forced to the ulnar side (the small finger side), there is reproduction of the pain. This is called Finkelstein's maneuver. The treatment consists of glucocorticoid injection and wrist splinting. In chronic cases, ultrasound guided percutaneous needle tenotomy with platelet rich plasma (PRP) may be required.

Another type of tendonitis closely related to DeQuervain's disease is called intersection syndrome. Repetitive motion is the usual cause. Tendonitis involving the wrist on the palm side is called flexor tendonitis.

The major nerves that extend into the hand pass through the wrist. The carpal bones are in the form of an arch and form the floor of the carpal tunnel. The roof consists of a tough piece of fibrous tissue called the flexor retinaculum. When there is swelling in the carpal tunnel, the median nerve, which passes through the carpal tunnel, becomes compressed. This causes carpal tunnel syndrome. Pain, numbness, and tingling involving the thumb, index, and middle fingers along with weakness in the hand are the major symptoms.

The ulnar nerve located on the little finger side of the wrist can also be compressed and this can cause numbness in the little finger.

The treatment of nerve entrapment disorders is discussed in other articles.

So what can cause pressure to build up in the wrist leading to pressure on these nerves?

There are many possible causes. These include forms of arthritis such as rheumatoid arthritis, psoriatic arthritis, gout, pseudogout, and lupus. Sometimes inflammatory forms of arthritis can cause fluid accumulation within the wrist that leads to increased pressure on structures inside the wrist joint.

Hypothyroidism (underactive thyroid), acromegaly (excessive growth hormone), diabetes and pregnancy can also do this.

Other nerves such as the radial nerve and posterior interosseous nerve run along the top of the hand and when pinched, usually by trauma, can cause numbness and tingling of the top of the hand and weakness.

A ganglion cyst can arise from either the joint or a tendon. These cysts are usually located on the top of the wrist. The primary symptom is swelling. The cysts can be aspirated and injected with glucocorticoids.

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