484 



THE MUSCULAE SYSTEM. 



The spermatic funiculus passes over the base of the triangle, covered over by the 

 aponeurosis of the obliquus externus. Behind the funiculus, and forming the floor 

 of the triangle, is the fascia transversalis partially covered, in the medial portion of 

 the triangle, by the falx inguinalis of the obliquus internus and transversus muscles. 



Middle arcuate ligament 



Vena caval opening 

 Aortic opening >.__ 



(Esophageal opening in diaphragn 



Anterior ramus 

 of twelfth 

 thoracic nerve 

 Quaclratus_ 

 lumborum 

 Ilio-hypogastric_ 

 nerve 



Ilio-inguinal 



Lateral 



cutaneous nerve 

 of thigh 



Femoral nerve 3 



Genito-femoral 

 nerve 1 



Obturator ne^ 



Descending branch 

 of fourth lumbar 1 " 



nerve 



Anterior ramus 



of fifth lumbar 



nerve 



Medial and 

 I lateral lunibo- 

 . I costal arches 

 Ant. ramus of tw 

 thoracic nerve 

 ..Quadratus 

 lumborum 

 -Ilio-hypogastrie 

 nerve 

 ilio-inguinal 



-Psoas major 



Genito-feinoral 

 nerve 



Lateral 



.cutaneous nerve 

 of thigh 



Iliacus 



Lumbo-sacral 

 trunk 



Femoral nerve 



Obturator nerva 



FIG. 430. THE DIAPHRAGM AND POSTERIOR ABDOMINAL WALL. 



Inguinal Hernia. For an account of the anatomical relations of the inguinal cana 

 to the various forms of inguinal hernia, see the section on " Applied Anatomy."" 



Nerve-Supply. The nerve-supply of the majority of the foregoing muscles is derived fron 

 the anterior rami of the lower six thoracic nerves. The pyramidalis muscle is innervated b; 

 the last thoracic nerve. The cremaster muscle receives its supply from the genito-femora 

 nerve (L. 1. 2.). 



Actions. (1) The chief action of these muscles is to retract the abdominal walls. B 

 compressing the contents of the abdomen, they are powerful agents in vomiting, defaecatioi 



