MUSCLES OF THE SHOULDER AND ARM. 3 1 



pass to the spine of the scapula, and are inserted along 

 the greater portion of its anterior edge. There is usually 

 a space between this and the anterior division near the 

 origin of the fibres, which is filled up with fat, connec- 

 tive tissue, lymphatic glands, etc. 



c. The Posterior Trapezius arises above the spi- 

 nous processes' of the anterior thoracic vertebrae in a 

 continuous line with the middle trapezius. The fibres 

 pass obliquely forward to be inserted along the pos- 

 terior edge of the outer or vertebral portion of the 

 spine of the scapula. 



In man these three divisions are more completely 

 united to form a single trapezius muscle. 



Ctii the three divisions of the trapezius at their in- 

 sertions and reflect the cut ends dor sally to their origins. 

 The following muscles will be exposed. 



2. The Rhomboideus Minor. It arises from the 

 dorsal mid-line above the spinous processes of the 

 posterior cervical vertebrae, just beneath the origin of 

 the trapezius. The fibres pass obliquely to the scapula 

 and are inserted into the anterior angle of the vertebral 

 margin. 



a. The OcciPiTO ScAPULARTS. Lying along the inner 

 margin of the rhomboideus minor is a narrow band of 

 muscle, the occipito scapularis, which arises from the 

 occipital bone and is inserted into the scapula along 

 with the rhomboideus, the two forming one muscle at 

 the insertion. This muscle is known also as the rhom- 

 boideus capitis or rhomboideus occipitalis in humaa 

 anatomy. 



3. The Rhomboideus Major arises from the spi- 

 nous processes of the four or five most anterior tho- 

 racic vertebrae — its origin being in a continuous line 

 with that of the rhomboideus minor, from which 



