OF THE ABDOMEN. 



285 



of the lower ribs, and Internal intercostal muscles. Its inner surface is lined by 

 the fascia transversalis, which separates it from the peritoneum. Its lower border 

 forms the upper boundary of the spermatic canal. 



Lumbar Fascia (fig. 166). The vertebral aponeurosis of the Transversalis divides 

 into three layers, an anterior, very thin, which is attached to the front part of the 



Fig. 165. The Transversalis. Rectus, and Pyramidalis Muscles. 



T i n 



apices of the transverse processes of the lumbar vertebra, and, above, to the lower 

 margin of the last rib, forming the ligamentum arcuatum externum ; a middle 

 layer, much stronger, which is attached to the apices of the transverse processes ; 

 nnd a posterior layer, attached to the apices of the spinous processes. Between 

 the anterior and middle layers is situated the Quadratus lumborum, between the 

 middle and posterior the Erector spinse. The posterior lamella of this aponeurosis 

 receives the attachment of the Internal oblique ; it is also blended with the apo- 

 neurosis of the Serratus posticus inferior and with that of the Latissimus dorsi, 

 forming the lumbar fascia. 



