288 



PRACTICAL ANATOMY. 



ligament and the iliac crest for two inches. Trace the muscle to its insertion 

 into the lower border of the twelfth rib and into the transverse processes of the 

 four upper lumbar vertebra;. Now place the kidney in its original position on 

 this muscle. This muscle lies in front of the erector spinaj muscle. In fact, 

 these two muscles form a guide to operations on the kidney. See whether you 

 can demonstrate on your work these structures, in the following relation from 

 behind forward : (i) The quadratics Itiinboriun ; (2) the- lumbar fascia; (3) the 

 last thoracic nerve, the ilio-hypogastric and ilia-inguinal nerves ; (4) the fatty 

 capsule of the kidney ; (5) the kidney. In operations on the kidney from behind, 



Quadratua lumboruxn 



Paoas parvuB 



Psoaa magnuB 



Interlransversalis 

 anterior 



Quadratus lumborum 



FIG. 197. PSOAS, ILIACUS, AND QUADRATUS LUMBORUM. 



you would find the above relations. Study the above relations until you have a 

 perfect picture of all these structures in your mind. The lower end of the kidney 

 is about one and one-half inches above the iliac crest. 



The psoas magnus muscle in its relation to vessels and nerves has been 

 previously described. The muscle has a strong synergist in the iljacus. These 

 two are sometimes spoken of as one muscle, with two heads or parts the ilw- 

 psoas. The two muscles are inserted into the lesser trochanter of the femur. 

 By this action, when the thigh is the fixed point, they draw the pelvis forward, 

 rotating the same on the heads of the femur. They thus antagonize the gluteus 

 maximus. The psoas magnus arises from the sides of the bodies of the last thor- 



