MYOLOGY 63 



of the humerus and passes to an insertion upon the ex- 

 tremity of the olecranon. Innervation of these five ex- 

 tensor muscles is by the radial nerve. 



C. MUSCLES OF THE FOREARM 



The muscles of the forearm or antibrachium may also 

 be classed as flexors and extensors. 



Of flexors there are seven, these being 



Mm. palmaris longus flexor carpi radialis 



pronator teres pronator quadratus 



flexor digitorum sublimis flexor carpi ulnaris 

 flexor digitorum profundus 



M. palmaris longus (figs. 13, 15, 29) is a bipennated 

 muscle arising by tendon fibers from the medio-distal 

 part of the medial epicondyle of the humerus. The broad 

 tendon extending from it is inserted into the palmar fascia. 



M. pronator teres (figs. 13, 29) has origin from the 

 medial epicondyle and the aponeurosis common to this 

 muscle and the flexor carpi radialis. Insertion is along 

 the middle half of the medial border of the radius. 



M. flexor digitorum sublimis (figs. 14, 15, 29) is 

 simple and Hes deep to the palmaris longus and the first 

 head of the flexor digitorum profundus. It originates 

 from the medial epicondyle of the humerus. Three ten- 

 dons leave the muscle mass and passing superficial to most 

 of the other pahnar tendons, each branch extends to one 

 of the three middle digits. 



In Teonoma the muscle is larger and there are four 

 divisions of the tendon, the fourth extending to digit five. 



M. flexor digitorum profundus (figs. 13, 14, 15, 29) 

 arises by three heads, as follows: 



Caput i is a bipennated muscle, superficial to and lying 

 medio-craniad of the palmaris longus. It has origin from 

 the -"ledial epicondyle of the humerus and deep attachment 



