Carpal tunnel

In the human body, the carpal tunnel or carpal canal is the passageway on the palmar side of the wrist that connects the forearm to the hand.Carpal tunnelCarpal tunnelWrist joint. Deep dissection.Anterior, palmar, view.Wrist joint. Deep dissection.Anterior, palmar, view.Wrist joint. Deep dissection.Anterior, palmar, view.Carpal tunnel and thenar and hypothenar eminencesCarpal tunnel In the human body, the carpal tunnel or carpal canal is the passageway on the palmar side of the wrist that connects the forearm to the hand. The tunnel is bounded by the bones of the wrist and flexor retinaculum from connective tissue. Normally several tendons from the flexor group of forearm muscles and the median nerve pass through it. There are described cases of variable median artery occurrence. The canal is narrow, and when any of the nine long flexor tendons passing through it swell or degenerate, the narrowing of the canal may result in the median nerve becoming entrapped or compressed, a common medical condition known as carpal tunnel syndrome. The carpal bones that make up the wrist form an arch which is convex on the dorsal side of the hand and concave on the palmar side. The groove on the palmar side, the sulcus carpi, is covered by the flexor retinaculum, a sheath of tough connective tissue, thus forming the carpal tunnel. On the side of the radius, the flexor retinaculum is attached to the scaphoid bone, more precisely its tubercle, as well as the ridge of trapezium. On the ulnar side it is attached to the pisiform and hook of hamate. The narrowest section of the tunnel is located a centimetre beyond the mid-line of the distal row of carpal bones where the sectional area is limited to 1.6 cm2. The tendons of the flexor digitorum superficialis and profundus pass through a common ulnar sheath, while the tendon of the flexor pollicis longus passes through a separate radial sheath. The mesotendon shared by these tendons is attached to the radial and palmar walls of the carpal tunnel. Superficial to the carpal tunnel and the flexor retinaculum, the ulnar artery and ulnar nerve pass through the ulnar tunnel/Guyon's canal. Ten structures pass through the carpal tunnel, most of them flexor tendons (not the muscles themselves): The flexor carpi radialis (one tendon), is often incorrectly stated to travel within the carpal tunnel. More precisely, it travels within the fibers of the flexor retinaculum which forms the roof of the carpal tunnel, rather than running inside the tunnel itself.