1 66 THE MUSCLES. 



The bicipital arch (Fig. 65, /') is a tendinous arch formed 

 over the biceps muscle. Its outer or lateral pillar is formed 

 by the tendon of the pectoralis minor (0), to which may be 

 added part of the latissimus {q) tendon. Its inner or medial 

 pillar is formed by the conjoined tendon of the teres major and 

 latissimus dorsi (Fig. 79, d'), while the xiphihumeralis (Fig. 

 65, p)y cutaneus maximus (Fig. 62, b), and epitrochlearis 

 (Fig. 65, r) are connected with one or the other pillar or with 

 the muscles composing them. The caudal portion of the deep 

 layer of the pectoralis major (Fig. 65, /) may be connected 

 with the inner pillar. 



M. brachialis (Fig. 79, i) Fig. 75, /). — From the lateral 

 surface of the humerus to the ulna. 



Origin (Fig. 83, gy g') from a long V-shaped line two to 

 four millimeters wide on the lateral surface of the humerus. 

 The apex of the V is just distad of the teres minor tubercle [d). 

 Its dorsal limb (^') extends along the lateral supracondyloid 

 ridge to a point opposite the proximal margin of the supra- 

 condyloid foramen ; its ventral limb {g) extends in the direc- 

 tion of the deltoid ridge to the middle of the bone. No 

 muscle-fibres take origin between the two limbs. The fibres 

 converge and end in a flat tendon which joins the tendon of 

 the clavobrachial (Fig. 79, k). 



Insertion (Fig, 87, c). — The dorsal portion of the depressed 

 rough area on the lateral surface of the ulna just distad of the 

 semilunar notch. 



Relations. — Outer surface with the acromiodeltoid (Fig. 

 75, f), the caput laterale of the triceps (Fig. 75, Ji), the 

 brachioradialis (Fig. 75, /'), and the proximal end of the ex- 

 tensor carpi radialis longus (Fig. 75, /). Inner surface with 

 the humerus. Medial edge with the pectoralis major (Fig. 

 65, /) and the biceps (Fig. j^j , g). 



Action. — Flexor of the antibrachium. 



M. triceps brachii. — The triceps muscle of the cat, like 

 that of man, is divisible (as its name indicates) into three main 

 portions. These are a lateral portion (caput laterale), an 

 intermediate or long portion (caput longum), and a medial por- 

 tion (caput mediale). The first two correspond to the simi- 



