DISSECTION OF THE BACK 



43 



vertebrae, and also to the posterior part of the crest of the 

 ilium. The costal slips of origin interdigitate with the lower 

 digitations of the external oblique muscle of the abdominal 

 wall. 



The fibres of the latissimus dorsi converge rapidly as they 

 approach the lower part of the scapula. The highest fibres 

 pass almost horizontally towards this point ; the lowest 

 fibres ascend almost vertically ; whilst the intermediate 



FIG. 19. Diagram of the Lumbar Fascia. 



1. Serratus posterior inferior. 



2. Latissimus dorsi. 



3. Transversus abdominis. 



4. Obliquus internus. 



5. Obliquus externus. 



6. Fascia transversalis. 



7. Sacrospinalis. 



8. Quadratus lumborum. 



9. Psoas major. 



fibres show varying degrees of obliquity. As a result of this 

 convergence of fibres, the muscle is greatly reduced in width ; 

 and it sweeps over the inferior angle of the scapula in the 

 form of a thick, fleshy band, which winds round the lower 

 margin of the teres major muscle to gain insertion, by means 

 of a narrow, flat tendon, into the floor of the intertubercular 

 sulcus of the humerus (Fig. 33, p. 79). This insertion cannot 

 be studied at present, but will be seen later on. With the 

 teres major muscle the latissimus dorsi forms the posterior 

 fold of the axilla. At first it is placed on the dorsal aspect of 



