96 



HANDBOOK OF ANATOMY 



Poupart's ligament the thickened free edge of the external 

 oblique muscle from the anterior superior spine of the ilium to 

 the spine of the pubis. 



The movement of rotation of the spinal column can be 

 defined as the approximation of the twelfth rib of the one side 

 to the iliac crest of the other. It is carried out by the diagonal 

 : muscles of the trunk. Thus rotation to the left i.e., turning 

 the body so tha"t the right twelfth rib is brought nearer to the 

 left iliac crest, is caused by the following muscles : 



Right obliquus externus abdommis. 



Left obliquus interims abdominis. 



Left latissimus dorsi. 



Left serratus posticus inferior. 



Rotation to the right, by the opposite muscles acting together. 

 This movement is made possible by the directions of the fibres 

 of the muscles concerned, and the fact that the external oblique 

 muscle of each side is inserted into the ivhole of the pubic crest, 

 so that the right external oblique gets some of its fibres inserted 

 into the left pubis, and vice versa, consequently is able to pull 

 its own side of the trunk over to the other. 



Muscles of the Thorax. 



This group of muscles can equally well be called the muscles of 

 respiration, as they are the ones that raise the ribs or otherwise 

 enlarge the cavity of the thorax, and make respiration possible. 



Muscle. 



Origin. 



Diaphragm From the ventral surface of 

 the ensi form cartilage ; from 

 I the ventral surfaces of the 

 cartilages of the lower six ribs 

 interdigitating with trans- 

 versalis ; by two crura from 

 the fronts of the bodies of 

 the upper lumbar vertebrae 

 three on the right side, two 

 on the left which decussate 

 in front of the aorta ; and 

 from the arcuate ligaments, 

 which are thickenings in the 

 fascia covering psoas and 

 quadratus lurnborum 



Insertion. 



It is inserted into a 

 large trilobed central 

 tendon, which is de- 

 veloped in the muscle 

 itself, and has no 

 bony attachment 



Nerve-supply. 



Phrenic 



