MUSCLES OF THE ANTEEIOR EXTREMITY. 87 



65, 66. M. anconaei s. extensores antibracJtii (Fig*. 76 aa). 



Dugès, epicondylo-cubital and epitrocUo-cubital, n. 80, 81. 



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

 spring", the one from the ep'iconclylus lateralis, the other from the 

 epicondylus medialis ; 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. fricejw. 



C. Mi'SCLES OF THE HaXU. 



(I.) Muscles on the palmar surface, 

 (i) Muscles common to all the digits. 



67. 3L flexor diffitoruin commmm and «?. pabuaris Lrevis (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, apotieurosis palmaris. Into the 

 outer border of this aponeurosis is inserted the m. pahnark lrevis 

 (Fig. 77 ph) ; 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. M. ahductor pollicis (Figs. 77, 78 ap). 



Dugès, cubito-poUicien, n. 100. 

 This short muscle arises from the upper border of the lower 

 extremity of the radio-ulnar, passes transversely outwards, and is 

 then inserted into the anterior border of the rudimentary thumb. 



69. J/, adductor ]ioUicis (Figs. 77, 78 ad.p). 



Dugès, sous-carpo-pollicien, n. loi. 



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

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

 with the abductor pollicis into the thumb. Several fibres of the 

 extens. dig. II brevis are also inserted into the thumb. As this 

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

 is capable are very limited. 



