290 A MANUAL OF ANATOMY. 



inner side of the front of the forearm to the wrist, the 

 posterior passes backward to a similar distribution to the 

 posterior surface of the forearm. 



The triceps muscle shows at the inside of the arm and 

 should be cleaned, and the musculospiral nerve and the 

 superior profunda artery traced between its two lower 

 heads. 



(5) The musculospiral nerve. This nerve is the direct 

 continuation of the posterior cord. It is found first behind 

 the axHlary, then to the inner side of it and the brachial 

 artery, and disappears with the superior profunda artery by 

 entering the musculospiral groove or canal between the two 

 lower heads of the triceps muscle. 



DISSECTION. 



Remove the deep fascia from the forearm as low as the annular ligament 

 of the wrist. 



Carefully clean the following structures : 



Pronator Radii Teres. Fig. 66. 



Origin. By the common tendon from the lower half- 

 inch of the internal condyloid ridge and the internal con- 

 dyle, for the upper head ; from the inner margin of the 

 coronoid process of the ulna, by the lower and smaller head ; 

 also from the intermuscular septum between it and the 

 flexor carpi radialis. 



NOTE. It will be stated here for once, to save repetition, that all the mus- 

 cles arising from the internal condyle by the common tendon also arise from 

 the intermuscular septum between each other. 



Insertion. Into the rough oval impression on the outer 

 surface of the radius at its middle. 



Nerve Supply. By the median, which passes between its 

 two heads. These filaments come from the sixth cervical 

 nerve. 



