15. The subscapularis (Fig. 77, _a_, and p. 161). Near its glenoid end,
its glenoid and coracoid borders are separated by triangular intervals
from the adjacent muscles. Transect the muscle by a line connecting the
apices of these triangles. Carry an incision from the middle of this one
to the middle of the vertebral border of the scapula, and reflect the
muscle on both sides of this incision,--thus determining its area of
origin. Reflect the humeral end without injuring the capsule of the
joint.
16. Dissect the supraspinatus (Fig. 75, _a_, and p. 159). Cut the strong
fascia free from the border of the scapula and its spine. Then transect
the muscle and reflect it, being careful not to injure the capsule of
the joint.
17. The spinodeltoideus (Fig. 75, _e_, and p. 156). Find its two
borders, beginning with the caudal one. In freeing the very short
cranial border do not injure the acromiodeltoideus (Fig. 75, _f_).
Transect and reflect the spinodeltoid.
18. The acromiodeltoideus (p. 157, and Fig. 75, _f_). Transect and
reflect.
19. The infraspinatus (p. 160, and Fig. 75, _c_). Locate the borders in
the region of the great scapular notch. It is difficult to separate the
glenoid border from the adjacent teres minor (Fig. 80, _c_). The
separation should be begun at the humerus. Transect the muscle at the
great scapular notch and reflect. Be careful not to injure the teres
minor (Fig. 80, _c_).
20. The teres major (p. 163, and Fig. 75, _d_; Fig. 77, _c_) should be
cut near its junction with the latissimus dorsi (Fig. 77, _e_).