Wrist

• E Trapezium ( trapezium )
• 1 spoke ( radius) 2 Elle ( ulna ) 3 metacarpal bones ( metacarpals )

The wrist is the composite of several sub- joints joint ( articulatio composita ) at the hand of mammals. In the four-footed animals, it is also known as pastern. It is next to the finger joints to the joints of the hand (Latin manus articulationes ).

When people are referred to as wrist joint between the radius and carpal bones ( radiocarpal, " wrist joint " ) as well as between the two rows of carpal bones ( articulatio mediocarpalis, " distal wrist "). In a broader sense, the other joints of the wrist are classified under this term, the support as so-called tight or loose joints ( amphiarthroses ), the two main joints in their function, however, only show a small range of motion. In most animals there is also a connection between the ulna and the carpal bones ( articulatio ulnocarpea ). In addition, counting the tight joints between the carpal bones ( articulationes intercarpales ) and between carpal and metacarpal bones ( articulationes carpometacarpales ) generally to the pastern ( articulatio carpi ).

All partial joints act together as a functional unit and allow flexion (flexion ) toward the palm ( palmar flexion ), stretching ( extension) direction hand back ( dorsal ) and Abspreizbewegungen (abduction ) toward your thumb ( radial deviation ) and direction of the little finger ( ulnar deviation ).

Proximal carpal joint

The middle of the body nearer ( proximal ) carpal joint called humans, the articulated connection between the middle of the body distant (distal) end of the spoke (facies articular carpi radialis ) and three of the proximal carpal bones (ossa carpal bones ), the navicular ( scaphoid ) the lunate ( lunate ) and the triangular bone (os triquetrum ). In addition, the intermediate hinge plate ( articular disc ) of the distal ulnar- joint involved in joint formation, which mediates between the carpal bones and the ulna. In most vertebrates, however, are both Elle ( articulatio ulnocarpea ) and spoke ( articulatio radiocarpea ) with the carpal bone in conjunction.

To the edges of the bone and cartilage at the intermediate hinge plate, a thin, loose joint capsule is fixed, which is enhanced by irradiating several bands. The joint space is unbranched and sometimes contains fat folds ( plicae synovial ).

The proximal wrist of man is functionally considered an ellipsoid or Eigelenk ( articulatio ellipsoidea ), which has two degrees of freedom:

• Diffraction ( palmar flexion, toward palm) up to about 80 ° and extension ( dorsiflexion direction back of the hand ) up to about 70 °
• Abspreizbewegungen (abduction or adduction ) and spoke ( radial abduction, actually more accurately Radialadduktion, so the thumb side ) up to about 20 ° or back to Elle ( ulnar deviation, to the little finger side ) up to about 40 °.

Distal carpal joint

The middle of the body more distant carpal joint ( articulatio mediocarpalis ) - rarely referred to as mid- carpal joint, in animals, the mean joints days of Vorderfußwurzelgelenks representing - shows a roughly S-shaped joint space between the proximal and distal row of carpal bones. It is composed of the individual joints between each pair of adjacent bone and acts functionally with the articulated joints of the carpal bones of a number of interrelated ( articulationes intercarpales ) as a unit. The joint capsule is on the palm of the hand tightly, while on the hand backside limp and forms numerous folds of fat from.

The wrist of the midsection more distant is a toothed hinge joint ( articulatio ginglymus ). The schematic curve is shown in Figure II as a red line. It is limited in its range of motion due to its curved shape, as well as ligaments and joint capsules. It cooperates with the proximal wrist, as a functional unit.

Intercarpal

The intercarpal ( articulationes intercarpales ) denote the articulated joints of the carpal bones of a series with each other.

The intercarpal are - as the carpometacarpal joints - so-called loose joints ( amphiarthroses ), which are reinforced by numerous band trains so that they can hardly move. The joint capsule is situated closer to limp body from the middle and distant from the center of the body located taut. These are so-called secondary joints, among which there are increase the mobility of the carpal bones and thus the mobility of the adjacent main joints ( radiocarpal articulation and mediocarpalis ) increase.

The intercarpal between the pisiform ( pisiform ) and the triangular bone (os triquetrum ), the so-called pisiform joint ( articulatio ossis pisiformis or articulatio carpi ossis accessorii ) is an independent joint with an independent joint capsule and independent joint space.

Means wrists

Carpometacarpal joints

The carpometacarpal joints, the connection of the distal carpal bones with the second to fifth metacarpals ( articulationes carpometacarpales II - V) in humans is not directly associated with the wrist, but always expected in animals to the pastern. They are - as the intercarpal - so-called loose joints that are reinforced by numerous band trains so that they can hardly move. It is secondary joints, which increase the movability between the carpal bones and the metacarpal bones and thus the mobility of the adjacent main joints ( radiocarpal articulation and mediocarpalis ) increase.

The carpometacarpal joint ( articulatio carpometacarpalis pollicis or trapezometacarpal joint I) is an exception to the five carpometacarpal joints as it does not form a loose joint, but a real and thus freely movable joint in contrast to them. It refers to the articulated connection between the large trapezium ( trapezium ) and the metacarpal bone of the first finger, so the thumb ( metacarpal or metacarpal of the thumb ). There is a saddle joint ( articulatio sellaris ) and is required primarily for the juxtaposition ( opposition) of the thumb over the other fingers, and therefore has in humans is central to grasping.

Intermetakarpalgelenke

The Intermetakarpalgelenke ( articulationes intermetacarpales ) are the articulated connections between the metacarpal bones of a series with each other. They are - as the intercarpal and carpometacarpal joints, the - amphiarthroses which are reinforced by numerous band trains so that they can hardly move. Increase the mobility of the metacarpals with each other and thus the mobility of the adjacent main joints ( radiocarpal articulation and mediocarpalis ).

Bands

The individual joints of the wrist to be supported by a plurality of bands which reinforce the joint capsule and cause movement. For a schematic overview see diagram II

• Mediate between forearm bones and the proximal carpal bones sidebands Elle lateral ligament ( ulnar collateral ) and
• Lateral band spokes ( radial carpal collateral ligament ),

• Ligament and palmar radiocarpale
• Ligament radiocarpale dorsal,

• Single bands Ligamentum carpi radiatum: It refers to a complex of bands ( ligamentum radiocarpale palmar, ligament intercarpal palmar and ligament carpometacarpale ) on the palm of the hand, ( capitatum Os) initiated from the cusp of the top leg and all flexor tendons house with the median nerve ( median nerve ),
• Ligament and pisohamatum

• Ligaments intercarpalia palmaria,
• Ligaments intercarpalia dorsalia and
• Interosseous ligaments intercarpalia.

• Ligament pisometacarpale,
• Ligament and palmar carpometacarpale
• Dorsal ligament carpometacarpale.

Development

At first glance, the upper extremities of the people seem to have little in common with the pectoral fins of the fish, but the basic construction is quite comparable.

As can be seen in Figure III, Elle (1) and spoke (2 ) have remained almost unchanged in the course of development. Similarly, the metacarpal bones ( metacarpals ) ( 3). A significant reduction of carpal bones has taken place. The middle of the body nearer ( proximal ) row of carpal bones is punctured. The no longer existing in humans Centralia brown. The middle of the body more remote carpal bone ( distal row ) are hatched.

In birds, the reduction of the carpal bones is the most advanced. Here are of the proximal row, only the radial carpal bone and ulnar present while the distal row is fused with the metacarpal bones to Carpometacarpus (→ bird skeleton). Therefore, in the wrist come in birds only two joints days - between forearm and carpal bones and carpal bones and Carpometacarpus - before.

Diseases

One of the most common diseases of the wrists, is the carpal tunnel syndrome ( CTS). Here, the median nerve ( the median nerve ) is often damaged by pressure. This can be caused previous wrist bone near break (fracture ), rheumatic diseases or overuse ( computer mouse, bicycle handlebars, etc.). However, there is often no identifiable cause. The damage to the ulnar nerve at the wrist ( Loge de Guyon 's syndrome ) is much rarer.

The most common damage caused by injury ( trauma ) are a joint near broken spokes ( distal radius fractures ) and a fracture of the scaphoid. In principle, all the bones of the wrist can break or fall with torn ligaments from their structure. Other diseases are tendinitis, a repetitive strain injury syndrome and a ganglion. Arthrosis of first carpometacarpal joint is quite common and is referred to as the first carpometacarpal joint.

In domestic dog puppies can be seen as the developmental disorder Carpal Laxationssyndrom occur, which is characterized by over-or under stretching.

Study opportunities

A modern form of diagnosis is next computed tomography ( CT) and magnetic resonance imaging ( MRI), the wrist mirroring ( arthroscopy ), which can take place under local anesthesia or arm ( brachial plexus ) anesthesia. The latter should only be performed at centers where also appropriate therapy can be carried out immediately, otherwise a second operation under general anesthesia with all the risks is often necessary.