Articulationes carpometacarpales

The distal row of carpal bones together with the proximal phalanges (Ossa metacarpi 2- 5) form stiffened joints (amphiarthroses). These joints are fixed from the side of the palm (palmar) and the side of the back of the hand (dorsal) by tight ligaments (Ligg. metacarpalia dorsalia, palmaria and interossea). The metacarpophalangeal joint of the thumb is an exception and for this reason is much more mobile than the other individual fingers.

Metacarpophalangeal joint

In the thumb saddle joint (Articulatio carpometacarpalis pollicis) the large polygon bone (Os trapezium) and the metacarpal bone (Os metacarpale 1) of the thumb interact. Since it is a saddle joint, 3 different directions of movement of the thumb are possible (3 degrees of freedom):

Bending (flexion) and stretching (extension),
Spreading movements
And the juxtaposition of the thumb against the other fingers (opposition and reduction). This is especially necessary for the so-called tweezer grip and without the opposition movement a person could hardly grip.

Carpal Band

The carpal ligament (retinaculum flexorum) stretches across the individual carpal bones. It runs between the hooked leg (Hamulus ossis hamatis) and the pea bone (Os pisiforme) to the hump of the large polygon bone (Tuberculum ossis trapezius) and the scaphoid bone (Tuberculum ossis scaphoidei). This forms a connective tissue channel called the carpal tunnel, which leads the median nerve in its center.

Diseases of the wrist

Carpal tunnel syndrome is particularly common in the wrist. This is caused by pressure and overload on the median nerve, which runs in the tunnel of the carpal ligament (retinaculum flexorum). The reason for this pressure damage can be previous wrist fractures, rheumatic diseases or overstrain.

The most common wrist injuries are a fracture in the part of the radius near the wrist (distal radius fracture), as well as a fracture of the scaphoid bone (Os scaphoideum). In principle, all bones of the wrist can break, but this is the one most frequently affected. Another common disease is an inflammation of the tendon sheath in the area of the tendon sheaths of the back of the hand.

Arthrosis of the metacarpophalangeal joint of the thumb can also occur. This is then called rhizarthrosis. X-rays, ultrasound and MRI of the hand are frequently used for diagnosis.

Pain in the wrist can have many different causes. Frequently, temporary pain in the wrist is simply due to overloading of the joint, especially after extensive sporting activities that put strain on the wrist, monotonous repetitive movements, for example when gardening, or a cramped position of the wrist over a longer period of time, for example when working at the computer for a long time. Wrist pain due to any of the above causes usually goes away by itself after a short time when the wrist is relaxed.

However, the pain can also have other causes. When you fall, you often support yourself with your hands reflexively. This can lead to a painful compression or even to a fracture of the bones in the hand area.

This can also cause a torn ligament in the wrist. Persistent pain in the wrist after a trauma should therefore always be clarified by a physician, so that a serious injury can be detected and treated early on. Often, a progressive wear and tear of the wrist is also the cause of the pain.

In the long term, arthrosis develops in the wrist, which is associated with worsening pain and, later on, with a restriction of movement. Initially, patients with arthrosis of the wrist only feel pain when they put more strain on the wrist. Later, the pain also occurs at rest and becomes increasingly severe over time.

Treatment in this case is initially with analgesic and anti-inflammatory drugs. In the final stage of arthrosis, these measures usually do not help any more, so that the joint must either be replaced by a prosthesis or stiffened in order to achieve lasting freedom from pain.People who work a lot with the computer suffer more often from the so-called mouse hand. In this case, the wrist hurts due to a cramped posture when operating the mouse and keyboard.

Special mousepads with a raised surface for the ball of the hand can help. Such overloading of the wrist can also lead to tendonitis, which can also cause pain in the wrist. The wrist is often additionally swollen.

Another possible cause of wrist pain is carpal tunnel syndrome. This is a bottleneck syndrome in the area of the wrist, which leads to a narrowing of the median nerve under the connective tissue plate at the wrist. The increased pressure on the nerve leads to unpleasant tingling and numbness, as well as pain in the wrist, which occurs especially at night. Tapping the inside of the wrist can also trigger an electrifying pain (so-called Hoffmann-Tinel signs). There are many different possible causes for wrist pain, so that a doctor should be consulted if the pain persists for a long time.