Corpus: Carpal tendon sheaths

The carpal tendon sheaths consist of three sheaths for the tendons of the flexors:

• Common sheath of the flexor muscles: Sheath of the flexor digitorum superficialis and profundus muscles
• Sheath of the flexor pollicis longus muscle tendon
• Sheath of the flexor carpi radialis muscle tendon

Unlike the synovial sheaths of the digits, the carpal tendon sheath is not reinforced by tight fibrous rings and crossbands.

The carpal tendon sheaths begin proximal to the proximal palmar carpal line and extend to just above the bases of the metacarpal bones, distal to the flexor retinaculum of the hand. In adults, there is typically a connection with the digital tendon sheath of the little finger.