396 JAMES CRAWFORD WATT 



normal accessory heads of origin of the biceps brachii are given 

 off. 



From the lower free edge of the muscle and from the main 

 tendon there arises an aponeurotic strip which gradually nar- 

 rows as it passes down the arm and forms a band arching over 

 the biceps muscle and inserting into the medial epicondyle 

 and the medial epicondylar ridge of the humerus. This band 

 is the chondroepitrochlearis muscle, and is not an uncommon 

 structure, being frequently found in the adult (8 times in 64 

 subjects, Le Double). Tt is much more frequent in females than 

 in males. It is a normal part of the musculature of many of 

 the lower animals, being known under various other names in 

 cheiroptera, bears, foxes, Dasypus, Echidna, Batrachia and 

 Cetacea, and is believed to be homologous with the tensor plicae 

 alaris of birds (Le Double). 



Pectoralis minor (fig. 8, P. Mi) 



Origin. Statements differ in various textbooks as to the 

 extent of origin of this muscle, some (e.g., Piersol) say the 

 third to fifth ribs, others (e.g., Morris) include the second rib 

 also. In this instance the more extensive origin occurs. 



Insertion. The insertion is into the upper surface of the 

 coracoid process and the outer part of the costocoracoid mem- 

 brane is so intimately blended with this part of the muscle 

 that I have debated whether or not to call it a second inser- 

 tion into the middle third of the clavicle, an attachment which 

 is occasionally exhibited. The lowest fibers are attached to the 

 medial surface of the coracobrachialis muscle, an insertion 

 which has been noted in other cases by Winslow (vide Le 

 Double). 



SHOULDER MUSCLES 



The deltoid, supraspinatus, infraspinatus, teres minor, teres 

 major, and subscapularis are all present, and normal in extent. 



