THE MUSCULATURE 41 



gin from dorsal fascia (connective tissue along mid- 

 line of the back) : insertion on lower jaw. 



251. Dorsalis scapulae. Covering suprascapula. Origin 

 from suprascapula: insertion on humerus. 



252. Latissimus dorsi. Caudal and dorsal to dorsalis 

 scapula^. Origin from dorsal fascia: insertion on 

 humerus. 



253. Longissimus dorsi. A longitudinal muscle, caudal 

 and ventral to the latissimus. Origin from urostyle: 

 insertion on occipitals. It is marked by a number of 

 transverse white lines, the septa tendinea. 



254. Coccygeo-sacralis. At the lateral margin of the 

 caudal end of the longissimus. Origin from urostyle: 

 insertion on sacral vertebra. 



255. Coccygeo-iliacus. Caudal and lateral to coccygeo- 

 sacralis by which it is covered cephalad. Origin from 

 urostyle: insertion on ileum. 



256. Obliquus externus. The broad lateral muscle of the 

 body wall. Origin from dorsal fascia: insertion on 

 ventral aponeurosis (corresponding to dorsal fascia 

 on ventral side). One portion (pars scapularis) at 

 the cephalic end connects the suprascapula with the 

 sternum. 



Cut through the obliquus externus and note ventral to it: 



257. Transversus, a similar sheet, but with its fibers at 

 a different angle. Origin from ileum, fascia dorsalis 

 and the fourth vertebra: insertion on ventral 

 aponeurosis. 



Carefully pull the depressor mandibulce cephalad and lift 

 suprascapula exposing the folloiving muscles: 



258. Rhomboideus anterior, at the cephalo-mesial border. 

 Origin from dorsal fascia and fronto-parietals: inser- 

 tion on ventral surface of suprascapula. 



