n. (pl. retinacula) a thickened band of tissue that serves to hold various tissues in place. For example, flexor retinacula are found over the flexor tendons in the wrist and ankle.
In structure, the hand has a bony basis of eight small carpal bones in the wrist, ?ve metacarpal bones in the ?eshy part of the hand, and three phalanges in each ?nger – two only in the thumb. From the muscles of the forearm, 12 strong tendons run in front of the wrist. Of these, nine go to the ?ngers and thumb and are bound down by a strong band, the ?exor retinaculum, in front of the wrist. They are enclosed in a complicated synovial sheath, and pass through the palm and down the ?ngers. Behind the wrist, 12 tendons likewise cross from forearm to hand.
Forming the ball of the thumb and that of the little ?nger, and ?lling up the gaps between the metacarpal bones, are other muscles, which act to separate and bring together the ?ngers, and to bend them at their ?rst joints (knuckles).... hand
the space between the carpal bones of the wrist and the connective tissue (retinaculum) over the flexor tendons. It contains the flexor tendons and the median nerve.... carpal tunnel
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