268 ANATOMICAL TECHNOLOGY. 



rus only Iby loose connective tissue, which may be torn with the 

 tracer. 



Note here the median nerve and hracMal artery after their 

 passage through the Foramen epitrocMeare. Still keeping the 

 brachium flexed, separate the cephalic side of the muscle from the 

 series of antebrachial muscles arising from the cephalic side of the 

 humerus. The muscle may be divided just proximad of its union 

 with the claxio-deltoideus. 



§ 693. Origin. — By fleshy fibers from an irregular, long, v-shaped 

 line extending almost the whole length of the cephalic surface of the 

 shaft of the humerus. The apex of the « is represented by a trian- 

 gular area a little distad of the tubercle for insertion of the M. 

 micostalis. 



The dorsal and longer branch of the r) extends dorso-distad to 

 near the middle of the length of the bone, thence distad to the crista 

 epicondylaris, which it follows to opposite the proximal end of the 

 Fm. epitrocMeare. 



The ventral branch runs ventro-distad parallel with the crista 

 deltoidea, then distad to about the junction of tlie middle and distal 

 thirds of the bone. 



Each of these branches is 2-4 mm. wide, and is really therefore 

 a long and narrow area rather than a line. The triangular space 

 between them does not give origin to fibers. 



Insertion. — From this peculiar origin the fibers converge to form a flat tendon .5-1 cm. 

 wide, which is closely attached by its ectal surface to the ental surface of the tendon of 

 the M. clavo deltoideus. The tendon of the brachialis is inserted upon the dorsal portion of 

 the depressed rough area on the caudal aspect of the ulna just distad of the greater sig- 

 moid notch and about midway between the dorsal and ventral margins of the bone. 



This account of the M. hracMnlis is derived mainly from the illustrated Thesis of 

 Homer Collins, B. S., a special student in the Anatomical Laboratory of Cornell Univer- 

 sity. The dotted lines upon Fig. 68, 71 approximately include the outline of the v-sliaped 

 line, but they should be double. 



M. EXTENSOR (CARPI) RADIALIS LONGIOR. 



§ 694. Synonymy. — The human muscle of the same name, G., A, 415, Q., A, I, 216; 

 "premier radial," S.-D., A, II, 359 ; part of the " extenseur anterieur du metacarpe" Ch., 

 A, 277 ; part of the anterior extensor of the metacarpus, Ch. (FL), A, 262 ; extensor carpi 

 radialis longior. Mi v., B, 151. 



Figures. — Cephalic aspect (74) ; caudal aspect (75) ; origin area (71). 



General Description. — From the epicondylar ridge of the humerus to the proximal 

 end of the indical metacarpal. 



