8 4 



THE UPPER EXTREMITY 



Teres minor 



Infraspinatus 



Triceps (outer 

 head) 



ment of the humeral heads 



are 



Brachialis 

 Musculo-spiral 



exhibited in the dissected 

 part. 



The caput laterak of the 

 triceps arises from the lat- 

 eral and posterior aspect of 

 the body of the humerus, 

 proximal to the sulcus 

 for the radial nerve. 

 It takes origin, by short 

 tendinous fibres, along a 

 line which descends verti- 

 cally from the insertion of 

 the teres minor above to 

 the upper border of the 

 sulcus for the radial nerve. 

 But it also derives fibres 

 from a strong aponeurotic 

 bridge or arch, which is 

 thrown over the groove, 

 so as to give protection to 

 the a. profunda brachii 

 and the radial nerve. The 

 strength and position of 

 this arch can be tested by 

 thrusting the handle of 

 the knife distally and 

 laterally in the sulcus for 

 the radial nerve, and along 

 the course of the nerve 

 and artery under the lateral 

 head of the triceps. By 

 its distal end the arch is 

 connected with the lateral 

 intermuscular septum. 



The caput mediate of the 

 triceps is placed distal to 

 the sulcus for the radial 

 nerve. It sends upwards, 

 on the posterior aspect of 

 the humerus, and along the medial margin of the groove, a 



Medial epi- 

 condyle 



FIG. 36. Dorsal aspect of the Humerus 

 with Attachments of Muscles mapped out. 



