678 A MANUAL OF ANATOMY 



before it the peritoneum forming that fossa. It then passes through the 

 internal abdominal ring, and traverses the entire length of the inguinal canal, 

 from which it emerges through the external abdominal ring into the scrotum, 

 thus forming a complete external oblique inguinal hernia. Throughout its 

 entire course the hernia lies in front of the spermatic cord, and its descent is 

 arrested at the upper part of the testis, which can be felt at its lower and back 

 part. The bowel may be arrested at any part of the inguinal canal, the 

 hernia being then called incomplete, and forming what is known as a bubono- 

 cele. In its descent the bowel elongates and carries before it certain invest- 

 ments from the structures to which it is related, these investments being 

 called the coverings of the hernia. The first covering of this form of hernia, 

 as of the other varieties, is derived from the parietal peritoneum, the par- 

 ticular part being that which forms the external inguinal fossa, and this 

 constitutes the sac. The other coverings are simply those of the spermatic 

 cord, which are all superadded to the sac. 



The coverings, enumerated in order from within outwards, are as follows : 



1. Parietal peritoneum, which forms the sac. 



2. Subperitoneal fat or areolar tissue. 



3. Fascia transversalis, from the margins of the internal abdominal ring, 

 forming the infundibuliform or internal spermatic fascia. 



4. Cremasteric or middle spermatic fascia, at the lower border of the internal 

 oblique muscle. 



5. Intercolumnar or external spermatic fascia, from the pillars of the 

 external abdominal ring. 



6. Tunica dartos. 



7. Skin. 



A short distance below the internal abdominal ring the subperitoneal fat and 

 infundibuliform fascia become united, and are known as the fascia propria. 



The sac is composed of the following parts : (i) the moxith, which is the 

 opening by which its interior communicates with the general peritoneal 

 cavity ; (2) the neck, which is the constricted part immediately beyond the 

 mouth ; and (3) the body. The neck of the sac is on a level with the margins 

 of the internal abdominal ring, and the deep epigastric vessels lie immediately 

 on its inner side. 



The seat of stricture may be (i) at the external abdominal ring ; (2) at the 

 Icrwer border of the internal oblique muscle; or (3) at the neck of the sac, 

 the last being the most common situation. 



Internal Direct Inguinal Hernia. — This variety is called internal because 

 the hernia, as it leaves the abdominal cavity, is internal to the deep epigastric 

 artery, and direct, from its straight course through the abdominal parieties. 

 The course of this variety is as follows : the hernia enters the internal inguinal 

 fossa, elongating before it the peritoneum forming that fossa. It then 

 passes through the inner two-thirds of Hesselbach's triangle, and so reaches 

 directly the external abdominal ring without traversing the inguinal canal. 

 Having emerged through the external ring it descends into the scrotum, thus 

 forming a complete internal direct inguinal hernia, which is in front of, and 

 internal to, the spermatic cord. It is to be noted (i) that there is no natural 

 opening in the fascia transversalis over the inner two-thirds of Hesselbach's 

 triangle, as there is external to the deep epigastric artery, and (2) that the 

 conjoined tendon covers the inner two-thirds of Hesselbach's triangle. The 

 coverings of this variety, enumerated in order from within outwards, are as 

 follows : 



1. Parietal peritoneum. 



2. Subperitoneal fat or areolar tissue. 



3. Fascia transversalis. 



4. Conjoined tendon. 



5. Intercolumnar or external spermatic fascia. 



6. Tunica dartos. 



7. Skin. 



If the hernia occurs suddenly, rupture of the conjoined tendon may take 

 place, in which cases the bowel would pass through the fissure. The seat of 



