226 ABDOMEN 



vessels, where it is attached to the pectineal line or pecten 

 of the superior ramus of the pubis, behind the falx 

 inguinalis (O.T. conjoined tendon), with which it is partially 

 blended. 



Annulus Inguinalis Abdominalis (Abdominal Inguinal Ring). 

 It has been noted that the transversalis fascia is pierced by 

 the spermatic cord. The opening through which it passes is 

 called the abdominal inguinal ring (O.T. internal abdominal 

 ring). The margin of the ring is prolonged downwards on 

 the cord as the internal spermatic fascia. It follows, there- 

 fore, that the opening can be defined, from the front, only by 

 an artificial dissection, viz. by dividing the internal spermatic 

 fascia around the cord and pushing it upwards with the 

 handle of the knife. The ring thus denned lies about 

 12.5 mm. (half an inch) above the inguinal ligament, at a 

 point midway between the symphysis pubis and the anterior 

 superior spine of the ilium. Through the opening the 

 dissector will see the extra-peritoneal fat, upon which the 

 transversalis fascia rests, and, just medial to the opening, the 

 inferior epigastric artery is visible through the fascia, pursuing 

 its oblique course upwards and medially. If the handle of 

 the knife is now introduced into the ring and carried laterally 

 between the fascia and extra-peritoneal fat, the attachments 

 of the fascia to the inguinal ligament and to the iliac crest 

 can be demonstrated. 



Canalis Inguinalis (Inguinal Canal). It has been shown 

 that the spermatic cord, in the male, and the round ligament, 

 in the female, pierce the abdominal wall above the inguinal 

 ligament. The passage which is formed for their transmission 

 receives the name of the inguinal canal. The canal is a 

 source of weakness to the abdominal wall ; and it is in con- 

 nection with it that inguinal hernia occurs, and the student 

 will understand, therefore, how necessary it is that he should 

 examine its position and its walls carefully from all points of 

 view. 



The inguinal canal 'is a narrow channel of about 38 mm. 

 (one inch and a half) in length. It begins at the abdominal 

 inguinal ring, which may be spoken of as its inlet, and 

 ends at the subcutaneous inguinal ring, which constitutes its 

 outlet. It is, consequently, very oblique, having a direction 

 almost directly medialwards, with a slight inclination down- 

 wards and forwards. So much for its length and direction ; 



