MUSCLES OF THE ANTEKlOli EXTREMITY. V 7 



65, 66. J/. aii<-iiaei s. extensores antilrachii (Fig. 76 aa). 



Duges, epicondylo-cubital and epitrochlo-cubital, n. 80, 8l. 



Both these muscles lie on the extensor side of the forearm ; they 

 spring 1 , the one from the epicondylvs laterals, the other from the 

 epteondyhu medial is; converging, they run downwards, enclose the 

 olecranon, and are inserted into the upper (dorsal) border of the 

 ulna, each forming a penniform muscle. They are extensors of the 

 forearm and assist the m. triceps. 



C. J/r* LE* OF THE 



(I.) Muscles on the palmar surface. 



(i) Muscles common to all the digits. 



67. 31. flexor digitorum commn.nu and m. palmari* Irevis (Fig. 



The origin and course of this muscle has been described above. 

 At its entrance into the palm it suddenly diminishes in size and 

 passes into a triangular aponeurosis, aponeurosis palmaris. Into the 

 outer border of this aponeurosis is inserted the m. palmaris Irevi* 

 (Fig. 77 pb] this latter muscle arises from the posterior or ulnar 

 border of the lower extremity of the radio-ulnar below the insertion 

 of the mm. anconaei, and runs obliquely downwards to this insertion. 



From the lower free border of the aponeurosis a number of 

 muscles arise which will be described with the rest of the digital 

 muscles. 



(2) Muscles of the rudimentary thumb. 



68. J/. aldudor pollicis (Figs. 77, 78 ap). 



Duges, cubito-pollicien, n. 100. 



This short muscle arises from the upper border of the lower 

 extremity of the radio-ulnar, passes transversely outwa-ixls, and is 

 then inserted into the anterior border of the rudimentary thumb. 



69. J/. adductor pollicis (Figs. 77, 78 a 



Duges, sous-carpo-pollicien, n. 101. 



This lies more superficially than the last, it arises from the 

 palmar surface of the os capitato-haMatuw, and is inserted together 

 with the aldudor poHici-s into the thumb. Several fibres of the 

 extent, dig. II Irevi* are also inserted into the thumb. As this 

 member is completely covered with skin, the motions of which it 

 is capable are very limited. 



