FASCIAE AND MUSCLES OF THE FOEEAEM AND HAND. 383 



hand. It is attached laterally to the navicular and large multangular; medially 

 to the pisiform and os hamatum; and it forms a membranous arch binding down, 

 in the hollow of the carpus, the flexor tendons of the fingers, and the median nerve. 

 It is divided into two compartments, the larger accommodating the tendons of the 

 flexors of the digits and the median nerve, the smaller (placed laterally) containing 

 the tendon of the flexor carpi radialis. There are three synovial membranes in 

 these compartments : one for the flexor carpi radialis tendon, and two others, 

 which often communicate together, enveloping the tendon of the flexor pollicis 

 longus and the flexor 

 tendons of the fingers 

 respectively. The 

 surface of the liga- 

 ment is crossed by 

 the palmar branches 

 of the median and 

 ulnar nerves ; by the 

 tendon of the palmaris 

 longus muscle, which 

 is attached to its sur- 

 face ; and by the ulnar 

 artery and nerve, 

 which are again 

 bridged over and pro- 

 tected by a band of 

 fibrous tissue, called 

 the volar carpal liga- 

 ment, which passes 

 from the pisiform 

 bone and the super- 

 ficial fascia to the 

 surface of the trans- 

 verse carpal ligament. 

 To the distal border 

 of the ligament are 

 attached the palmar 

 aponeurosis in the 

 centre, and the super- 

 ficial muscles of the 

 thumb and the mus- 

 cles of the little 

 finger on each side. 



Ligamentum 

 Carpi Dorsale. 

 The dorsal carpal 

 ligament (O.T. pos- 

 terior annular liga- 

 ment) is placed at a 



more proximal level than the transverse carpal ligament. It consists of an 

 oblique band of fibres about an^inch broad, continuous proximally and distally 

 with the deep fascia of the forearm and hand. It is attached laterally to the 

 lateral side of the distal end of the radius, and medially to the distal end of the 

 ulna (styloid process), the carpus, and the ulnar collateral ligament of the wrist. 

 It is crossed by veins, by the superficial ramus of the radial nerve, and by the 

 dorsal branch of the ulnar nerve. Six compartments are formed deep to it by 

 the attachment of septal bands to the distal ends of the radius and ulna. Each 

 compartment is provided with a mucous sheath, and they serve to transmit 

 the extensor tendons of the wrist and fingers in the following order from lateral 

 to medial side : 



(1) Abductor pollicis longus and extensor pollicis brevis, (2) Extensores carpi 



Palmar 

 aponeurosis " 



Thenar 

 eminence 



Hypothenar . 

 eminence 



PALMARIS BREVIS _ 



Transverse carpal 

 ligament 

 ABDUCTOR . 

 POLLICIS LONGUS 



FLEXOR CARPI RADIALIS ._ 

 PALMARIS LONGDS 



FLEXOR DIGITORUM / 



SUBLIMIS 1 



FLEXOR CARPI ULNARIS- .- 



FIG. 342. THE PALMAR APONEUROSIS. 



