164 THE MUSCLES 
2. Muscles of the Brachium or Upper Arm. 
M. clavobrachialis and the pectoralis group (Fig. 65, page 
109) lie partly in this region; they have been described. 
M. coracobrachialis (Fig. 77, £; Fig. 79, c).—A very 
short muscle covering the inner (medial) surface of the capsule 
of the shoulder-joint. It extends from the coracoid process 
to the proximal end of the humerus. 
Origin (Fig. 78, 2).—By a round tendon from the tip of 
the coracoid process. 
Insertion (Fig. 82, ¢) usually by fleshy fibres on an area 
five to eight millimeters long and about half as wide, which lies 
on the medial side of the humerus parallel with the ridge which 
runs from the dorsal end of the lesser tuberosity to the shaft 
and close to it. The proximal end of the area is about one 
centimeter from the proximal end of the head of the humerus. 
Relations. —Medial surface with the biceps (Fig. 77, g), 
pectoralis minor (Fig. 65, 0), and teres major (Fig. 77, ¢). 
Lateral surface with the capsule of the shoulder-joint. Dorsal 
border with the subscapularis (Fig. 77, a) and the long portion 
of the caput mediale of the triceps (Fig. 77, 7). 
Action.—Adducts the humerus. 
The part of the coracobrachialis just described is known as 
the short head. <A dong head is sometimes found. It is a 
conical bundle of fibres of varying size, which arises from the 
tendon of origin of the short head. It passes distad into a long 
and extremely slender tendon, the insertion of which varies 
greatly in different individuals. It is commonly on the humerus 
in the region of the supracondyloid foramen. 
M. epitrochlearis or extensér antibrachii longus (Fig. 
65, ~).—A thin, flat muscle on the inner or medial side of the 
brachium, from the lateral surface of the latissimus dorsi (Fig. 
65, g) to the olecranon process of the ulna. 
Origin from the lateral or outer surface of the ventral border 
of the latissimus dorsi (Fig. 65, g) near the insertion of the 
cutaneus maximus. Fibres are often attached to the teres 
major and the pectoralis minor. 
Insertion by a flat tendon which is closely connected with 
