34 MUSCLES 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 latisshnus extensor muscle. 



Cut through the latissimus dorsi at its insertion. 

 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 

 zuill then fall outzvard, displaying the folloiuing 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. 



15. 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 alons^ the vertebral margin of the scapula. 



