FOREARM, WRIST, AND HAND. 



forms the annular ligaments. The anterior annular ligament is 

 a wide band attached externally to the scaphoid and trape- 

 zium ; and internally to the pisiform and unciform. Arching 

 over the carpus it forms a small compartment externally for 

 the tendon of the Flexor carpi radialis, with its synovial 

 sheath; and a large compartment internally which transmits 

 the median nerve, the tendon of the Flexor longus pollicis in 

 one synovial sheath, and the flexor tendons of the fingers in 

 another sheath. The posterior annular ligament is a wide arid 

 oblique band lying somewhat higher and running from the 

 outer side of the radius to the lower end of the ulna, the car- 

 pus, and the carpal internal lateral ligament. Septal bands 

 running from it to the radius arid ulna divide it into six com- 

 partments, each with its synovial sheath. The compartments 

 are occupied, from without inward, by the tendons of the 

 Extensores (1) ossis metacarpi pollicis, and brevis pollicis; (2) 

 carpi radialis, longior and brevior; (3) longus pollicis; (4) 

 communis digitorum, and indicis; (5) minimi digit! ; (6) carpi 

 ulnaris. [337] 



The palmar fascia is a thick and triangular portion attached 

 by its apex to the lower edge of the anterior annular ligament, 

 and continuous laterally with the deep fascia. Its base sepa- 

 rates into four slips, for the fingers, which are connected by 

 transverse fibres (superficial transverse metacarpal ligament); 

 each slip divides in two parts, which are attached to the sides 

 of the metacarpo-phalangeal joints and proximal phalanges 

 of the fingers. [338] 



The digital sheaths are tubular envelopes which enclose the 

 flexor tendons, are continuous with the palmar fascia, and are 

 attached to the sides of the phalanges and interphalangeal 

 joints. They are loose and thin over the interphalangeal joints 

 but thickened (ligamentum vaginale) over the first two pha- 

 langes of each finger and the first phalanx of the thumb. 

 Synovial sheaths line the digital sheaths, enveloping the 

 flexor tendons, and extend into the palm; those of the little 



[169] 



