MUSCLES OF THE ABDOMEN. 201 



or three in the dorsal region, four in the lumbar 



region, one between the last lumbar and sacrum. 

 Insertion Small bundles of muscular fibres, arranged 



in pairs, which pass between the spinous processes. 

 Nerves Dorsal. 

 EXTENSOR COCCYGIS. 



Origin Posterior surface of sacrum ; it is rudimentary. 

 Insertion Posterior surface of coccyx. 

 Nerves Posterior sacral. 

 INTERTRANSVERSALES. 



Origin Six pairs on each side in the cervical region, 



three or four in the dorsal region, four in the lumbar 



region. 

 Insertion Pass between the transverse processes in 



the cervical region ; the bundles are separated by 



a distinct interval. 

 Nerves Dorsal. 



MUSCLES OF THE ABDOMEN. 



EXTERNAL OBLIQUE. 



Origin Eight inferior ribs by eight fleshy digitations 

 interdigitating with the pectoralis major and the 

 serratus magnus. 



Insertion Inserted into the anterior one-third of the 

 crest of the ilium, and into Poupart's ligament, which 

 is the reduplicated inferior edge of the aponeurosis 

 attached to the anterior superior spine of the ilium 

 and the spine of the pubes. The muscle, by its 

 aponeurosis, is also inserted into the linea alba for 

 its entire length. The aponeurotic tendon passes 

 entirely in front of the sheath of the rectus muscle. 

 Just above the point of insertion of Poupart's 

 ligament, the fibres of the aponeurosis of the ex- 

 ternal oblique diverge, leaving a triangular opening 



