422 



DISSECTION OF THE ABDOMEN. 



ligament inserted into the pectineal line; whilst along the upper part its 

 extent is determined only by the apposition of the muscles. 



In the female, the canal has the same length and boundaries, though it 

 is usually somewhat smaller. In that sex it lodges the round ligament. 



The internal abdominal ring (fig. 140) is an aperture in the fascia 

 transversalis, which is situate midway between the symphysis pubis and 

 the iliac crest, and half an inch above Poupart's ligament. It is oval in 

 form, the extremities of the oval being directed upwards and downwards, 

 and measures about half an inch; the fascia at its outer and lower parts is 

 stronger than at the opposite sides. 



Fig. 140. 



DISSI:CTIOX FOR INOUINAJ. HER.NMA. (Illustrations of Dissections.) 

 Muscles : Arteries : 



A. External oblique tendon, thrown down. a. Epigastric vessels. 



B. Internal oblique, the lower part raised. I. Offset of the circumflex iliac muscles, 

 c. Cremaster muscle in its natural position. 



D. Transversalis muscle with a free border. 



F. Spermatic cord. 



Q. Fascia transversalis. 



H. Conjoined tendon. 



Arching above and on the inner side of the aperture, is the lower border 

 of the transversalis muscle, D, which is fleshy in the outer, but tendinous 

 in the inner half. Below, it is bounded by Poupart's ligament. On the 

 inner side lie the epigastric vessels (a). 



This opening in the fascia transversalis is the inlet to the inguinal canal, 

 and through it the cord, or the round ligament, passes into the wall of the 

 abdomen. The external hernia enters the canal the same spot. All the 



