Anatomy of the wrist and hand
Last reviewed: 23.04.2024
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The wrist joint is formed by the joint surface of the radial bone and the distal surface of the articular disc, represented by the scaphoid, semilunar and trihedral bones.
Stability of the joint is provided by two lateral ligaments of the wrist: radial, attached to the styloid process of the radial bone and the scaphoid bone, and the ulnar, starting from the styloid process of the ulna and attached to the trihedral bone and partly to the pea. On the back and palmar side, the wrist joint is strengthened due to the dorsal palmar and radiocarpal ligaments. In the radiocarpal joint, flexion, extension, reduction, retraction and rotation are performed. Interphalangeal joints of the hand are located between adjacent phalanges of each finger. The ligamentous apparatus of the interphalangeal joints of the hand is represented by the palmar ligaments that run from the side surfaces of the blocks and are attached: one to the lateral surface of the phalanx - lateral ligaments, and others - to their palmar surface. The first thumb has one interphalangeal joint. On the palmar surface of the hand pass the tendons of the superficial and deep flexors of the fingers.
On the back of the wrist there is a wide reinforcing fibrous cord - extensor retinaculum, which consists of several ligaments forming 6 pockets or divisions, each of which has a synovial vagina for the tendons of the extensors of the hand passing there. In the first pocket, located near the styloid process of the radius, tendons of the tendon, the finger and the finger extensor, lie. The tendons of the long and short radius extensors of the wrist lie in the second pocket, lateral to the dorsal tubercle of the radius. In the third pocket, medial to the dorsal tubercle, the tendon of the long extensor of the fingers is located. In the fourth pocket lie the tendons of the extensors of the fingers and extensor of the index finger. In the fifth pocket is the tendon of the extensor of the little finger. In the sixth pocket - the elbow extensor of the wrist. On the inner or palmar side of the wrist, there is also a firming fibrous cord of the tendon of the flexor retinaculum, forming the carpal canal.
This fibrous ligament is medially attached to the pea-bones, and laterally to the hook-shaped bone, where it is divided into 2 layers, attached to the tubercles of the scaphoid and trapezoidal bones. The tendon of the radial flexor of the wrist is located between two layers of the fibrous strand, where the tendons of the deep and superficial flexors of the fingers, the tendon of the long flexor of the fingers and the medial nerve pass. The tendon of the long flexor of the fingers is located closer to the radial surface of the canal and has its own synovial vagina. The other 8 tendons of the flexors are enclosed in the common tendon vagina. On the wrist the tendons of the superficial flexors of the fingers are attached to the proximal part of the middle phalanx of the fingers. Tendons of the deep flexor of the fingers are attached to the base of the distal phalanx. Tendons of the flexor of the fingers are fixed to the phalanges with the help of anular ligaments.
The medial nerve.
The medial nerve is formed from the roots of C6-T1 with the possible participation of C5. It follows in the neuromuscular bundle on the shoulder with the brachial artery and ulnar nerve. In the distal part of the shoulder follows as part of the aponeurosis of the biceps muscle between the two heads of the round pronator.
The forearm is located between the superficial and deep flexors of the fingers. Rising up, the medial nerve enters the carpal tunnel. It innervates the round pronator, the radial flexor of the fingers, the long palmar, the superficial flexor of the fingers, the lateral part of the deep flexor of the fingers, the long flexor of the thumb, the square pronator, the tenar muscles, the vermicular muscles 1 and 2 of the phalanx of the fingers; and also provides a sensitivity of 1, 2, 3 fingers and half 4 fingers from the palmar surface.
The nerve passes through the carpal canal laterally and above the flexor tendons of the fingers. In the tunnel lies between the radial flexor of the wrist and the superficial flexor of the fingers deeper than the long palmar tendon. The tendon of the ulnar flexor of the wrist is located medially at the ulna and is enclosed in the synovial membrane.
Between the tendons of the flexor of the fingers and the tendon of the elbow flexor of the wrist, the ulnar artery and the nerve are located. The ulnar nerve lies lateral to the pea, but is medial to the hook of the hook-shaped bone. Here the ulnar artery lies anteriorly and lateral to the nerve.
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