176 



Muscles of the Upper Extremity. 



232, The Muscles at the 



Posterior Keg-ion of the 



Hum ems. 



Muscles at the ante- 

 rior region of the h u m e- 

 rus, continued. 



M. brachialis anticus s. inter- 

 ims (see Fig. 231) arises by 

 an outer and inner fleshy pro- 

 cess from the outer and inner 

 surfaces of the humerus, and 

 is inserted into the coronoid 

 process of the ulna. (Flexes the 

 forearm.) 



Muscles at the poste- 

 rior region of the humerus: 

 M. triceps sen extensor Irachii 

 arises by three heads : The long 

 head, Caput longum s. Anconaeus 

 loncjiis from the axillary border 

 of the scapula below the glenoid 

 cavity; the external head, Caput 

 externum s. Anconaeus externus, 

 from the outer part of the 

 posterior surface of the humerus; 

 the internal or short head, Caput 

 internum s. Ireve s. Anconaeus inter- 

 ims from the posterior surface 

 of the humerus. It is inserted 

 by a tendon of insertion into the 

 olecranon process of the ulna. 

 (Extends the forearm.) 



M. anconaeus guartus (see 

 Fig. 240) arises from the 

 external condyle of the humerus, 

 and is inserted into the posterior 

 angle and outer surface of the 

 upper third of the ulna. (Also 

 extends the forearm.) 



