MUSCLES 33 



ess of the ulna. The clavicle is attached to the 

 under side of this muscle, in front of the shoulder- 

 joint. Just before the cephalo-humeral is inserted 

 on the ulna, it receives fibres from the first divis- 

 ion of the pectoralis. (Plates II. and IV.) 



2. The Middle Trapezius Muscle arises along the 

 mid-dorsal line, immediately posterior to the origin 

 of the cephalo-humeral. Its fibres converge to their 

 insertion upon the spine of the scapula. (Plate II.) 



3. The Posterior Trapezius Muscle arises a little 

 posterior to the origin of the middle trapezius, 

 along the mid-dorsal line, above the neural proc- 

 esses of the thoracic vertebrae. It is inserted on 

 the spine of the scapula, above the insertion of the 

 middle trapezius. (Plate II.) 



4. The Latissimus Dorsi is the very broad muscle 

 covering a great part of the dorsal portion of the 

 abdomen and thorax. It takes its origin from the 

 neural processes of the last nine dorsal vertebrae, 

 and by fascia from the neural processes of the 

 lumbar vertebrae. Its fibres converge anteriorly, 

 and, blending with the adjacent fibres of the pos- 

 terior division of the pectoralis muscle, are in- 

 serted, together with another muscle, the teres 

 major, by a flat tendon, on the inner side of the 

 shaft of the humerus. The insertion is just below 

 the lesser tuberosity. (Plates II. and IV.) 



5. The Cleido-mastoid is a narrow strip of muscle 

 arising from the clavicle and extending to the 

 mastoid process. (Plates II. and IV.) 



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