86 



THE MUSCLES. 



broader and is inserted into the whole length of the lower (volar) 

 ridge of the radio-ulnar. It is a powerful flexor of the forearm. 



(II.) Muscles of the extensor surface. 



63. M. exteusor digitorum communis longus (Fig. 75 ecV). 

 Dugès, huméro- sus-digital, n. 95. 

 This muscle lies on the outer border of the forearm ; it arises in 

 common with the short head of the flexor antibr, lateralis superfici- 

 alis from the epicond)jliis lateralis, and from the surface above it ; 

 it runs downwards along the outer side of the forearm, in order to 

 pass into an aponeurosis on the back of the hand, which expands 

 upon the third, fourth, and fifth fingers, and ends between them in 

 a free concave border. This aponeurotic expansion is connected 

 with the tendons of the extensor brevis digitorum. 



63*. M. abductor digiti II [i. e. j^ollicis) longus (Fig. 74 ei). 

 *Dugès, cubito-métacarpien, n. 87. 

 This muscle lies between the foregoing and the jiexor antibrachii 

 lateralis sujoerjicialis, and appears superficially in the interval between 

 Fig. 76. them. It arises from the lateral surface of the 



radio-ulnar, and runs obliquely over the m. jiexor 

 antibracJiii lateralis jprofundns and the hinder 

 extremity of the radio-ulnar towards the second 

 finger into the metacarpal bones of which it is 

 inserted. 



64. M. extensor carin ulnaris s. ulnaris post. 



(Fig. 76 ec). 



Dugès, epicondylo-sous-carpien, n. 85. — Klein, 

 abductor carpi intermix. 



This muscle has a somewhat narrow origin 

 from the epicondylus lateralis ; during its course 

 through the forearm, where it lies between the 

 mm. ancoîiaei on the one side and the extensor 

 digitorum communi on the other, it becomes 

 broader and is inserted into the outer surface of 

 the carpus in the following manner. By one 

 tendinous slip it is attached to the palmar 

 border of the os pyramidale, by a second slip 

 to the outer border of the os capitato-hamatum. 



This latter slip is usually connected in its dorsal portion with the 



extensor digitorum communis brevis. 



Mnscles of forearm of 

 Rana esculenta, dorsal 

 view. 

 aa M. anconaei. 

 ec M. extens. digit. 



communis. 

 Fd M. flex, digit. 



