THE HAND. 



403 



the metacarpal bones at their distal extremities. By this arrangement short 

 channels are formed on the front of the lower ends of the metacarpal bones, 

 through which the flexor tendons pass. Dr. W. W. Keen describes a fifth slip as 

 frequently found passing to the thumb. The intervals left in the fascia between 

 the four fibrous slips transmit the digital vessels and nerves and the tendons of 

 the Lumbricales. At the points of division of the palmar fascia into the slips 

 above mentioned numerous strong, transverse fibres bind the separate processes 

 together. The palmar fascia is intimately adherent to the integument by dense 

 fibro-areolar tissue, forming the superficial palmar fascia, and gives origin by its 

 inner margin to the Palmaris brevis : it covers the superficial palmar arch, the 



art fri;. 

 Digital nerves. 



Fr<;. '.'41. Palmar fascia. (From a preparation in the Museum of the Royal College of surgeons of 



England.) 



tendons of the flexor muscles, and the branches of the median and ulnar nerves, 

 and on each side it gives off a vertical septum, which is continuous with the 

 interosseous aponeurosis and separates the lateral from the middle palmar group 

 of muscles. 



The lateral portions of the palmar fascia are thin, fibrous layers, which cover, 

 on the radial side, the muscles of the ball of the thumb, and, on the ulnar side, the 

 muscles of the little finger ; they are continuous with the dorsal fascia, and in the 

 palm with the central portion of the palmar fascia. 



