MUSCLES OF THE SHOULDER AND ARM. 35 
MUSCLES OF THE ARM. 
16. The Biceps Muscle lies on the inner and ven- 
tral face of the humerus. Its anterior end is covered 
over by the insertion of the pectoralis muscles upon 
the humerus. The biceps arises by a single strong 
tendon from the edge of the glenoid fossa (coracoid 
process), the tendon passing through the capsular liga- 
ment of the joint. The muscle is inserted by a strong 
tendon chiefly into the ulna, though it is attached also 
to the radius by a smaller slip. 
17. The Coraco-brachialis is a small muscle lying 
to the inner side of the proximal end of the biceps. 
It arises by a single tendon from the coracoid 
process, passes over the head of the humerus, and is 
inserted into the inner side of the humerus just 
beneath the tendon of the teres major. 
18. The Triceps Brachialis is the large mass of 
muscle lying along the dorsal aspect of the humerus. 
It serves to extend the forearm. In the dog it has 
four divisions. : 
a. The largest division is an irregular muscle, 
formed apparently by the fusion of two muscles; it 
arises along the posterior margin of the scapula, the 
attachment being especially strong near the glenoid 
fossa, and is inserted into the olecranon process of the 
ulna. The other three divisions lie between this one 
and the humerus, and agree pretty well in position 
with the three heads of the triceps in man. 
b. ‘he most internal of these three divisions arises 
from the humerus at the insertion of the coraco- 
brachialis, and also bya line of fascia along the middle 
third of the humerus. 
