34 MUOSCLES -OF THE SHOULDER /AND ARM. 
latissimus gives off a muscular slip, which passes along 
the arm, superficial to the triceps, to be inserted into 
the olecranon process of the ulna. It might be called 
the datessemus extensor muscle. 
Cut through the latesstmus dorst at rts tnsertion. 
Cut across also the pectoralis group of muscles and the 
loose connective tissue, nerves, blood-vessels, etc., which 
bind the arm to the side of the thorax. The scapula 
well then fall outward, displaying the following mus- 
cles. 
13. The Teres Major—the muscular band lying 
along the posterior margin of the scapula. It is in- 
serted by a flat tendon into the upper part of the 
humerus, between the biceps and coraco-brachialis 
muscles. 
14. The Sub-scapular Muscle is the large mass of 
muscle filling up the sub-scapular fossa. It has three 
or four tendinous lines separating the muscle in- 
completely into fasciculi. The fibres converge to- 
ward the head of the humerus, into which they are 
inserted, the tendon passing through the capsular 
ligament of the shoulder-joint. At the anterior 
margin of the scapula the sub-scapular muscle fuses 
more or less with the supra-spinatus. 
I5. The Serratus Magnus is the large muscle, con- 
necting the vertebral margin of the scapula to the 
wall of the thorax. Anteriorly it fuses with the leva- 
tor anguli scapuli, the two constituting in this animal 
in reality but one muscle. The portion which arises 
from the transverse processes of the cervical vertebrae 
may be called the levator anguli scapuli, while the 
portion arising from the ribs is the serratus magnus. 
It springs from the first eight ribs by fleshy slips, and 
is inserted along the vertebral margin of the scapula. 
