364 MUSCLES ON THE ANTERIOR PART OF THE FOREARM. 



Inserted into the upper and external part of the process of 

 the ulna, called olecranon, and partly into the condyles of the 

 OS humeri, adhering firmly to the ligament. 



Use. To extend the forearm. 



2. Anconeus, 



Arises, tendinous, from the posterior part of the external 

 condyle of the os humeri ; it soon grows fleshy, and is continued 

 from the third head of the triceps. 



Inserted, fleshy, and thin into a ridge on the outer and pos- 

 terior edge of the ulna, being continued some way before the 

 olecranon, and covered with a tendinous membrane. 



Use. To assist in extending the forearm. 



Muscles situated on the Forearm. 



These may be divided into three classes, viz. 



1. The muscles which bend and extend the wrist, and of course the whole hand. 



2. Those which bend and extend the fingers exclusively. 



3. Those which act on the radius so as to roll it backwards and forwards on the 

 ulna ; which are called supinators and pronators. 



The flexors both of the wrist and fingers, and the pronators, lie on the front of 

 the forearm. The extensors and the supinators on the back. 



The flexors generally originate from the internal condyle of the os humeri, and 

 the parts adjacent to it ; the extensors from the external condyle of the same 

 bone, and the parts which are near it. 



In the following description they are arranged in the order in which they occur 

 in the dissection of the arm ; beginning with those which originate with the 

 internal condyle, without regard to their particular functions. 



Muscles on the anterior pari of the Forearm. 



1. Palmaris Longus, 



Arises, tendinous, from the internal condyle of the os 

 humeri, soon grows fleshy, and, after a short progress sends 

 off a long slender tendon. 



Inserted into the ligamentum carpi annulare, and into a 

 tendinous membrane that is expanded on the palm of the 

 hand, named aponeurosis palmaris; which, above, begins 

 at the transverse or annular ligament of the wrist, and, below, is 

 fixed to the roots of the fingers. 



