392 



ABDOMEN 



At the lateral margin of the rectus muscle the aponeurosis 

 of the internal oblique splits into two layers a superficial 

 and a deep. The superficial aponeurotic layer passes in front 

 of the rectus, and has already been seen to fuse with the 

 aponeurosis of the external oblique muscle. The deep layer is 

 carried medially behind the rectus, and becomes incorporated 

 with the subjacent aponeurosis of the transverse muscle. 

 But this arrangement does not hold good lower down than a 

 point about midway between the umbilicus and the pubes. 

 Below this point the aponeurosis does not split, but passes 



entirely in front of the 

 rectus to join the apo- 

 neurosis of the external 

 oblique. 



It is important to 

 mark exactly the rela- 

 tion which the lower 

 part of the muscle 

 bears to the spermatic 

 cord. At first the cord 

 lies behind the fleshy 

 fibres, but it soon 

 emerges, clothed by 



FIG. 147. Diagram to illustrate the relation 



of the lower border of the Internal Oblique the Cremaster muscle, 

 Muscle to the Cord, the Falx Inguinalis, and, as it is continued 



and the inguinal Canal. downwards and medi- 



O.I. Internal oblique muscle. ally tO the SubcutanCOUS 



C.T. Falx Inguinalis. inguinal ring, it lies in 



The position of the subcutaneous inguinal ring is f f ,, r i 



indicated by a dotted outline. 



neurotica inguinahs 



(O.T. conjoined tendon). Especially note the position of 

 the falx inguinalis in relation to the subcutaneous inguinal 

 ring. It lies immediately behind it, and gives strength to this 

 otherwise weak point in the abdominal parietes. 



M. Cremaster. This muscle supports the testis and 

 spermatic cord, and is consequently peculiar to the male. It 

 arises from the medial part of the inguinal ligament, and also 

 derives fibres from the lower border of the internal oblique 

 (rarely from the lower border of the transversus abdominis 

 muscle). The fleshy fibres descend upon the lateral and 

 anterior aspects of the cord in the form of loops, the con- 

 cavities of which are directed upwards. The depth to which 



