360 



DISSECTION OF THE ABDOMEN. 



as they 

 ascend to 

 tendon : 



differences 

 in the 

 pillars. 



intermixing, but the inner fibres of the two crura cross one another 

 in the following manner : Those of the right (e) ascend by the side 

 of the aorta, and pass to the left of the middle line, decussating with 

 the fibres of the opposite cms between that vessel and the opening of 

 the oesophagus. The fibres of the other cms (d) may be traced in 

 the same way, to form the right half of the cesophageal opening. In 

 the decussation the fasciculus of fibres from the right crus is generally 

 larger than, and in front of, that from the left. 



The pillars differ somewhat on opposite sides. The right (e) is 

 the larger of the two, and is fixed by tendinous processes to the 

 bodies of the first three lumbar vertebrae, and their intervertebral 

 substances, reaching down to the disc between the third and fourth 

 vertebrae. The left pillar (d) is situate more on the side of the spine, 



Two arched 

 ligaments, 



internal 



and 

 external. 



FIG. 137. UNDER SURFACE OF THE DIAPHRAGM. 



A. Diaphragm. 



B. Psoas inagnus. 



c. Quadratus lumborum. 



a. Left piece of the tendon of the 

 diaphragm. 



b. Middle, and c, right piece. 



d. Left, and e. right crus. 



/. Inner, and g, outer arched 

 ligament. 



h. Opening for vena cava, i, for 

 oesophagus, k, for aorta, j, for 

 splanchnic nerves. 



is partly concealed by the aorta, and does not reach so far as the right 

 by the depth of a vertebra, and it is even occasionally wanting. 



The arches (ligamenta arcuata) are two fibrous bands on each side 

 over the quadratus lumborum and psoas muscles, which give origin 

 to fleshy fibres. 



The arch over the psoas (lig. arcuat. internum; /) is the stronger, 

 and is connected by the one end to the tendinous part of the pillar 

 of the diaphragm, and by the other to the transverse process of the 

 first or second lumbar vertebra. 



The arch over the quadratas lumborum (lig. arcuat. externum; g) 



