264 ANATOMICAL TECHNOLOGY. 



here given to them are provisional and descriptive rather than designatory. They readily 

 separate, and no special directions for dissection are required. 



DV. INTERMEDIA. 



686. Synonymy. Straus-Durckheim (A, II, 350) calls this " le premier chef de 

 Fancone moyen " ; Mivart describes it as the fourth division of the triceps (B, 149). 

 Figures. In part (75) ; origin area (68, 71). 



Origin. By fleshy fibers from the dorsal surface of the surgical 

 neck of the humerus, and from the proximal part of the shaft. 

 Sometimes the attachment extends upon the arthral capsule. The 

 length of the area of origin equals about one sixth of the length of 

 the humerus. Its caudal border is encroached upon by the area 

 of insertion of the M. coracoideus, caput breve, but the cephalic 

 border is rounded, and embraced by the line of origin of the M. 

 ectotriceps. The triangular apex of the area lies between the ori- 

 gins of the caudal division next to be described and the M. brac7ii- 

 alis. The ventral border is indicated by the radial artery and 

 nerve which lie between it and the dv. caudalis. 



Insertion. At the junction of the middle and distal thirds of 

 the humerus the muscle ends in a slender, flat tendon which widens 

 slightly as it nears the elbow, rests in the furrow at the proximal 

 end of the bone, and is inserted into the oblique ridge which forms 

 the dorsal limit of the furrow, thus slightly ventrad of the ridge of 

 insertion of the meditriceps. Between the tendon and the floor of 

 the furrow is a synovial capsule. 



DV. CAUDALIS. 



687. Synonymy. Called by S.-D. (A, II, 350) " le second chef de I'ancone moyen " ; 

 it is the third division of Mivart (B, 149). 



Figures. Caudal aspect (75) ; origin area (70, 71). 



Origin. By fleshy fibers from a subtriangular area, a little 

 proximad of the middle of the dorso-caudal aspect of the humerus. 

 The length of the area equals about one sixth of the length of the 

 bone. Its apex points proximad, and is almost continuous with 

 the apex of the origin area of the Dv. intermedia. 



Along the caudal border of the distal part of the muscle runs 

 the ulnar nerve, and the radial artery and nerve cross the dorsal 

 border at about the junction of the proximal and middle thirds. 



Insertion. By short, tendinous fibers upon the caudal border 

 of the ventral aspect of the olecranon as far as the lip of the greater 

 sigmoid notch (Fig. 30). 



