166 THE MUSCLES. 
The bicipital arch (Fig. 65, 7’) 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 (7) tendon. Its inner or medial 
pillar is formed by the conjoined tendon of the teres major and 
latissimus dorsi (Fig. 79, @’), while the xiphihumeralis (Fig. 
65, f), cutaneus maximus (Fig. 62, 6), and epitrochlearis 
(Fig. 65, ~) 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, 7) may be connected 
with the inner pillar. 
M. brachialis (Fig. 79, 7; Fig. 75, 7).—From the lateral 
surface of the humerus to the len 
Origin (Fig. 83, g, 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 (Z). 
Its dorsal limb (g’) 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 ina flat tendon which joins the tendon of 
the clavobrachial (Fig. 79, 2). 
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, 4%), the 
brachioradialis (Fig. 75, &), and the proximal end of the ex- 
tensor carpi radialis longus (Fig. 75, 27). Inner surface with 
the humerus. Medial edge with the pectoralis major (Fig. 
65, /) and the biceps (Fig. 77, 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- 
