Wrist

The manus has a skeleton in which the carpal bones (ossa carpi), metacarpi metacarpi biceps and the finger bones of the hand are phalanges of the fingers (phalanges digitorum manus).

Bones of the wrist. The carpus has 8 short (spongy) bones arranged in 2 rows. In the upper (proximal) row, if viewed in the medial direction (from the thumb to the little finger), the following bones are found: scaphoid, semilunar, trihedral and pea-shaped. The lower (distal) row forms a polygonal (bone-trapezoid), trapezoidal, capitate and hook-shaped bones. The name of the bones reflects their shape. On the surfaces of each bone there are joint articulations for articulation with adjacent bones.

The scaphoid bone (os caphoideum) is large, has a convex surface that participates in the formation of the wrist joint. The semilunar bone (os lunatum) also has a convex proximal surface. The trihedral bone (os triquetrum) has a flat articular surface for articulation with a pea-like bone. The bony bone (os pisiforme) is the smallest of all bones of the wrist. This bone is located in the thickness of the tendon of the elbow flexor of the wrist and is a sesamoid bone.

Three bones of the first row with their upper (proximal) surfaces face the bones of the forearm and form an ellipsoidal articular head. The distal surfaces of these bones are directed toward the four bones of the wrist of the second row.

Bone trapezium (os traperium) has a saddle-shaped articular surface for articulation with the base of the first metacarpal bone. On the palmar surface of the bone-trapezium is a furrow, which from the lateral side is bounded by a tubercle. Trapezoid bone (os trapezoideum) resembles bone-trapezoid in shape. The head bone (os capitdtum) is the largest of the bones of the wrist. It has a head directed proximally and somewhat outwardly. The hook-shaped bone (os hamatum) on the palmar surface has a hook-shaped hook (hamulus ossis hamati).

The bones of the wrist form a bony arch, the convex side of which is facing posteriorly, and the concave side is anterior (toward the palm). As a result, a wrist groove (sulcus carpi) is formed on the palmar surface, bounded from the radial side by the tubercle of the scaphoid bone and the tubercle of the bone-trapezium, and on the ulnar side by the hook of the hook-shaped bone and the pea-bones.

Fifth bones. Pastern (metacarpus) includes five (IV) short tubular bones - metacarpalia bones (ossa metacarpalia). Each metacarpal bone consists of a base, a corpus and a caput. The bodies of metacarpal bones are triangular in shape, their tips thickened. Therefore, when connecting metacarpal bones to each other between their bodies remain interosseous gaps. From the palmar side of the body of metacarpal bones slightly concave, with the rear - slightly convex. The bases of II-V metacarpal bones at the proximal ends have flat articular surfaces for articulation with the bones of the second row of the wrist.

I metacarpale 1 is shorter and thicker than the others. On its base is a saddle surface for articulation with a polygonal bone. II metacarpal bone is the longest. The bases of II-V metacarpal bones have lateral articular surfaces for articulation with each other. The head of metacarpal bones is hemispherical, their convex articular surfaces serve for articulation with proximal phalanges of the fingers.

Bones of fingers. In the hand, the thumb is distinguished (pollex, s.digitus primus); index finger (index, s.digitus secundus); the middle finger (digitus medius, s.tertius) is the longest, ring finger (digitus anularis, s.quartus) and the little finger (digitus minimus, s.quintus).

Phalanges of fingers (phalanges digitorum). These are short tubular bones. Each finger, except I (large), has 3 phalanges: proximal (phalanx proximalis), middle (phalanx media) and distal (phalanx distalis). The thumb has only two phalanges - proximal and distal. The proximal phalanges are the longest, the distal ones are the shortest. There are bases of phalanx (basis phalangis), body of phalanx (corpus phalangis) and head of phalanx (caput phalangis). The bases of the proximal phalanges have articular fossa for articulation with the corresponding metacarpal bones. The bases of the middle and distal phalanges are provided with articular surfaces for articulation with proximal phalanges. The end of each distal (nail) phalanx is flattened and forms a tuberosity of the distal phalanx (tuberositas phalangis distalis).

In the bones of the upper limb, as well as in other bones, there are nutrient holes. Through these holes penetrate the vessels that feed the bone, and nerve fibers.

The movements of the wrist in the wrist, wrist and mid-joints around the frontal axis are possible in the range of 100 °, the withdrawal-reduction (around the sagittal axis) -80 °.

Flex the wrist: the elbow wrist flexor, the wrist flexor, the superficial flexor of the fingers, the deep flexor of the fingers, the long flexor of the thumb of the hand, the long palm muscle.

Unbend the brush: the muscles - the long and short extensor of the wrist, the elbow extensor of the wrist, the extensor of the fingers, the long extensor of the thumb of the hand, the extensor of the little finger.

Brushing is removed: the muscles are the wrist flexor of the wrist, the long and short extensors of the wrist (with simultaneous contraction).

Brush: the muscles are the elbow flexor of the wrist, the elbow extensor (with a simultaneous contraction).

The movements of the fingers of the hand are performed in the metacarpal joints around the frontal axis (flexion-extension), as well as retraction-the circular movements around the sagittal axis and passive rotation around the longitudinal axis. The thumb of the hand and the little finger can be opposed to each other. The movements of the thumb of the hand are performed by the following muscles.

Flexes the thumb: the long flexor of the thumb of the hand, the short flexor of the thumb of the hand.

Unbend the thumb: short and long extensors of the thumb of the hand.

Remove the thumb of the hand: long and short muscles that remove the thumb of the hand.

Lead the thumb: the muscle that leads the thumb of the hand.

Contrast: the muscle that opposes the thumb.

Bend the II-V fingers of the hand following muscles: superficial and deep flexors of the fingers (phalanges of these fingers also bend the interosseous and vermicular muscles).

Unbend fingers: the muscle is the extensor of the fingers.

Reduction to the middle finger - palmar interosseous muscles.

The distance from the middle finger is the rear interosseous muscles.