316 



THE MUSCLES 



The second head arises from the ol)li(iiie line on the anterior surface of the 

 radius. 



Insertion. — By four tendons into the middle of the sides of the second pha- 

 langes of the four fingers. 



Structure. — The first head arises by short tendinous fibres from the humerus 



Fig. 273. — Front of thk Foreakm : Second Layer of Muscles. 



Biceps 

 Trioepa 



Muscles of first layer 

 BracUialis antieus 



Flexor sublimls digitorum 



Fiercer carpi ulnaris 



Flexor carpi radialia 

 Falmaris lougus 



B rachio-radialis 



Extensor carpi radialis longior 



Supinator brevis 



Brachio-radialis 

 Flexor longus poUicis 



Extensor ossis metacarpi polUcis 

 Extensor brevis pollicis 



and ulna, and from tlic ligament between them. The second head, -which is much 

 smaller, by fleshy iibres which form a thin sheet covering a ]iart of the flexor longus 

 pollicis. ik'tween these two heads the median nerve and the ulnar artery are placed. 

 Converging from tliese two heads, the flesliv flbres occu]\y almost the whole breadth 

 of the forearm, but soon divide into a superflcial and deep plane. From the former, 



