MUSCLES OF THE THORACIC LIMBS. 161 
68, f). Inner surface with the scapula. Glenoid border with 
the teres minor (Fig. 80, c), the teres major (Fig. 75, 2), and 
the long head of the triceps (Fig. 75, g). ‘ 
Action.—Rotates the humerus outward. 
M. teres minor (Fig. 80, c).—A small muscle from the 
glenoid border of the scapula to the proximal end of the 
humerus. 
Origin (Fig. 76, ¢) by a sheet of tendinous fibres from the 
glenoid border of the scapula beginning about one-fifth the 
length of the border from the glenoid fossa and extending to 
its middle. It is often attached to the infraspinatus (Fig. 
80, 6) and the caput longum of the triceps (Fig. 75, g). 
Insertion (Fig. 83, @) by a short tendon into the tubercle 
just distad of the infraspinatus fossa on the great tuberosity of 
the humerus. 
Relations.— Outer surface with the spinodeltoideus (Fig. 
75, e), acromiodeltoideus (Fig. 75, /), and the infraspinatus 
(Fig. 80, 6). Inner surface with the lateral (Fig. 75, 4) and long 
(Fig. 75, ) heads of the triceps and the capsule of the joint. 
Action.—Assists the infraspinatus to rotate the humerus 
outward. 
B. MUSCLES ON THE MEDIAL SURFACE OF THE SHOULDER. 
(Fig. 77.) 
M. subscapularis (Fig. 77, a).—A triangular mass from 
the subscapular fossa to the lesser tuberosity of the humerus. 
Origin (Fig. 78, a@).—From the whole subscapular fossa 
except along the fusiform area for the attachment of the levator 
scapulz and the serratus anterior near the vertebral border, 
and except over a quadrangular area about one centimeter long 
near the glenoid angle. The origin is-by fleshy fibres directly 
from the periosteum except along two or three lines marked 
by oblique ridges. To these lines are attached tendinous fibres. 
At the glenoid border the area of origin sometimes occupies 
part or the whole of the surface of the fossa for the origin of the 
teres major, so that the teres arises from the fascia on the sur- 
face of the subscapularis. At the coracoid border some of the 
fibres may take origin from the adjacent fascia of the supra- 
spinatus (Fig. 77, @). 
