INTERNAL ABDOMINAL RING. 



827 



The fascia transversalis is a thin aponeurotic membrane, which lies between 

 the inner surface of the Transversalis muscle and the peritoneum. It forms 

 part of the general layer of fascia which lines the interior of the abdominal and 

 pelvic cavities, and is directly continuous with the iliac and pelvic fasciae. 



In the inguinal region, the transversalis fascia is thick and dense in struc- 

 ture, and joined by fibres from the aponeurosis of the Transversalis ; but it 

 becomes thin and cellular as it ascends to the Diaphragm. Below, it has the 

 following attachments: external to the femoral vessels, it is connected to the 

 posterior margin of Poupart's ligament, and is there continuous with the iliac 

 fascia. Internal to the vessels, it is thin, and attached to the pubes and pec- 

 tineal line, behind the conjoined tendon, with which it is united ; and, corre- 

 sponding to the point where the femoral vessels pass into the thigh, this fascia 

 descends in front of them, forming the anterior wall of the crural sheath. 



Fig. 448, Inguinal Hernia, showing the Transversalis Muscle, the Transversalis Fascia, 

 and the Internal Abdominal Ring. 



The internal abdominal ring is situated in the transversalis fascia, midway 

 between the anterior superior spine of the ilium and the spine of the pubes, 

 and about half an inch above Poupart's ligament. It is of an oval form, the 

 extremities of the oval directed upwards and downwards, varies in size in 

 different subjects, and is much larger in the male than in the female. It is 

 bounded, above, by the arched fibres of the Transversalis muscle, and inter- 

 nally, by the epigastric vessels. It transmits the spermatic cord in the male, 

 and the round ligament in the female, and from its circumference a thin, funnel- 

 shaped membrane, the infundibuliform fascia, is continued round the cord and 

 testis, inclosing them in a distinct pouch. When the sac of an oblique inguinal 

 hernia passes through the internal ring, the infundibuliform process of the 

 transversalis fascia forms one of its coverings. 



Between the transversalis fascia and the peritoneum is a quantity of loose 

 areolar tissue. In some subjects it is of considerable thickness, and loaded 

 with adipose tissue. Opposite the internal ring, it is continued round the sur- 

 face of the cord, forming a loose sheath for it. 



