External Abdominal Ring 303 



ing of the spermatic cord, and ot an oblique inguinal hernia. The 

 external abdominal ring, being the lower end of the inguinal canal, 

 transmits the spermatic cord or the round ligament. And, as the 

 spermatic cord is the more bulky of these two structures, the canal 

 and the ring are more capacious in the male than in the female, and 

 inguinal hernia, therefore, is more common among men than women. 



Femoral hernia a protrusion beneath Poupart's ligament is 

 more common in women, the great breadth of the pelvis necessitating 

 a wide space below the ligament, which the iliacus and psoas, and the 

 femoral vessels, but indifferently block up. 



In the case of a tumour in the upper part of the scrotum, if the 

 external ring contain nothing but the normal cord the swelling below 

 it can have no association with the abdominal cavity it is not a 

 hernia. The tip of the ringer need not be made actually to enter 

 the ring by invaginating the scrotum and thrusting it up ; but in every 

 case of scrotal tumour the cord should be examined just below the 

 ring. 



On account of the fascia lata being closely attached to Poupart's 

 ligament, tension of the fascia drags down the ligament and tightens 

 the aponeurosis of the external oblique. Therefore, before attempting 

 the reduction of an inguinal hernia, the thigh should be slightly flexed 

 and inverted. The hernia is rarely strangulated at the external ring, 

 because of the comparative slackness of its inner boundary ; the con- 

 striction is almost invariably in the neck of the peritoneal sac. 



The internal oblique has its 

 fibres running upwards and inwards, ^ 

 almost at right angles to those of 

 the external oblique, for the greater 

 strength of the abdominal wall ; the 

 directions of the fibres in the two 

 muscles are like those of the bars 

 of a lattice-work. The internal 

 oblique takes a fleshy origin from 

 the outer half of Poupart's ligament, 

 the anterior two-thirds of the iliac 

 crest, and the fascia lumborum, and 

 slopes upwards and forwards to be 

 inserted into the four lower costal 

 cartilages. As it approaches the 

 outer border of the rectus it becomes 

 aponeurotic, and then splits to en- 

 close the rectus. The anterior sheet 

 joins over the front of the rectus 

 with the. lamella of the external 

 oblique, to reach the linea alba, while the deeper layer passes to the 

 linea alba, along with the aponeurosis of the transversalis muscle 



