482 



THE MUSCLES AND FASCIA. 



FIG. 307. Front of the left forearm. Deep muscles. 



sheath, and are connected to each 

 other and to the phalanges by slender 

 tendinous filaments, called vincula 

 accessoria tendinum. One of these con- 

 nects the deep tendon to the bone be- 

 fore it passes through the superficial 

 tendon ; a second connects the two 

 tendons together, after the deep ten- 

 dons have passed through ; and a 

 third connects the deep tendon to the 

 head of the second phalanx. This last 

 consists largely of yellow elastic tissue, 

 and may assist in drawing down the 

 tendon after flexion of the finger. 1 



Four small muscles, the Lum- 

 bricales, are connected with the ten- 

 dons of the Flexor profundus in the 

 palm. They will be described with 

 the muscles in that region. 



Relations. By its superficial sur- 

 face, in the forearm, with the Flexor 

 sublimis digitorum, the Flexor carpi 

 ulnaris, the ulnar vessels and nerve, 

 and the median nerve ; and in the 

 hand, with the tendons of the super- 

 ficial Flexor ; by its deep surface, in 

 the forearm, with the ulna, the in- 

 terosseous membrane, the Pronator 

 quadratus ; and in the hand, Avith the 

 interossei, Adductor pollicis, and deep 

 palmar arch ; by its ulnar border, with 

 the Flexor carpi ulnaris ; by its radial 

 border, with the Flexor longus pollicis, 

 the anterior interosseous vessels and 

 nerve being interposed. 



The Flexor longus pollicis is situ- 

 ated on the radial side of the forearm, 

 lying on the same plane as the pre- 

 ceding. It arises from the grooved 

 anterior surface of the shaft of the 

 radius, commencing above, imme- 

 diately below the tuberosity and ob- 

 lique line, and extending below to 

 within a short distance of the Pro- 

 nator quadratus. It also arises from 

 the adjacent part of the interosseous 

 membrane, and generally by a fleshy 

 slip from the base of the coronoid 

 process. The fibres pass downward. 

 and terminate in a flattened tendon 

 which passes beneath the annular 

 ligament, is then lodged in the in- 

 terspace between the outer head of 

 the Flexor brevis pollicis and the 

 Adductor obliquus pollicis, and en- 

 tering an osseo-aponeurotlc canal 



Marshall, Brit, and For. Med.-Chir. Rev., 1853. 



