tailieunhanh - Anatomy at a Glance: Phần 2

The carpal tunnel is narrow and no arteries or veins are transmitted through it for risk of potential compression. The median nerve is how-ever at risk of compression when the tunnel is narrowed for any reason. This is the carpal tunnel syndrome and results in signs of median nerve and brevis motor and sensory impairment. | 38 The carpal tunnel and joints of the wrist and hand Thenar muscles Flexor carpi radialis Flexor pollicis longus Trapezium Trapezoid Ulna nerve and artery Hypothenar muscles Flexor retinaculum Median nerve Tendons of flexor digitorum superficialis Tendons of flexor digitorum profundus Hamate Capitate A diagrammatic cross-section through the carpal tunnel Radius Scaphoid Trapezium 1st metacarpal The wrist and carpal joints Mi Ulna Disc of fibrocartilage Midcarpal joint Articular cartilage Cephalic vein Flexor retinaculum Occasional communication The synovial sheaths of the flexor tendons Dorsal tubercle of radius Extensor pollicis longus Scaphoid First dorsal interosseous Extensor expansion Extensor pollicus brevis Radial artery Abductor pollicus longus The anatomical snuffbox 86 Upper limb The flexor retinaculum and carpal tunnel Fig. The carpal tunnel is formed by the carpal bones and the overlying flexor retinaculum. It is through this tunnel that most but not all of the forearm tendons and the median nerve pass. The flexor retinaculum is attached to four bony points the pisiform the hook of the hamate the scaphoid and the trapezium. The carpal tunnel is narrow and no arteries or veins are transmitted through it for risk of potential compression. The median nerve is however at risk of compression when the tunnel is narrowed for any reason. This is the carpal tunnel syndrome and results in signs of median nerve motor and sensory impairment. Note that the ulnar nerve and artery pass over the retinaculum and are thus outside the carpal tunnel. The synovial sheaths of the flexor tendons Fig. The diagram illustrates the arrangement of the synovial sheaths that surround the flexor tendons. It can be seen that flexor pollicis longus has its own sheath and flexor digitorum superficialis and profundus share one which ends in the palm except that for the little finger . The wrist radiocarpal joint Fig. Type the wrist is a