1136 SURGICAL AND TOPOGRAPHICAL AXATOMY 



(1) Median, or urachus; This interesting fa?tal relic, the intra-abdominal part 

 of the allantois, passes up between the apex of the bladder and the umbilicus, and 

 by so doing — (a) keej^s the bladder up, especially in early life, when the pelvic 

 cavity is but little developed; (6) it keeps the bladder well up so that it shall be 

 above the level of the urethra, and so more easily enii)tied; (c) it provides, by thus 

 keeping up the bhukler, that it shall enlarge in a diri'ction which will admit of the 

 greatest amount of distension, i.e. one between the lower or yielding part of the 

 abdominal wall and the hollow of the rectum, which is compressible. 



(2) The obliterated hypogastric arteries. These, the remains of vessels which 

 during fatal life carry the impure blood of the foetus out to the mother through 

 the umbilicus, run up and join the urachus at the umbilicus. In relation to these 

 cords are the following fossae : (a) An internal one, between the urachus and the 

 obliterated hyj)()gastric artery. This corresponds, on the anterior surface, to the 

 external al)dominal ring. Through this fossa comes direct inguinal hernia, (b) 

 Between the obliterated hypogastric artery and the deep epigastric artery, running 

 u]) wards and inwards to form the outer boundary of Hesselbach's triangle, is a 

 middle fossa. This is the smallest of all. (c) The external fossa is outside the 

 det'p epigastric artery. It is the most distinct of the three, from the way in which 

 the cord or round ligament passes down within a glove-like process of the trans- 

 versalis fascia. This fossa corresponds to the internal ring. 



Varieties of inguinal hernia according to the condition of the vaginal 

 process of peritoneum. — Inguinal hernia? have above been classified according 

 to thtiv relation to the deep epigastric artery. It remains to allude to the arrange- 

 iiicnt of these same hernia? according to the varying condition of the processus 

 funiculo-vaginalis. This pouch of peritoneum, which paves the way for the pas- 

 sage of the testis before this organ makes its start, eventually becomes the tunica 

 vaginalis below, in this fashion: Ver}^ soon after birth the process becomes oblit- 

 erated at two spots — one near the internal ring, and one just above the testicle. The 

 obliterative process, commencing first above and descending, and then, ascending 

 from below, the shrivelling continues until nothing is left save the tunica vaginalis 

 below. The following are possible outcomes from an imperfect obliteration of the 

 process — the first, alone, is common: — 



(1) If the process does not close at all, a descending hernia is called congenital. 

 This may make its way into the scrotum. The testis is now enveloi)ed and con- 

 cealed by the hernia. 



(2) If the process is closed only above, i.e. near the internal ring, the hernia 

 may make its way behind the unobliterated processus funiculo-vaginalis. To this 

 variety of inguinal hernia the name infantile has been given. Its only importance 

 is that during any operation for such a hernia three layers of peritoneum would 

 have to be divided before the hernial contents could be reached. If, again, during 

 some exertion, the hernia rupture the obliterating septum which has formed above, 

 the condition of things to be dealt with is practically that of a congenital hernia. 



(3) If the processus funiculo-vaginalis be closed l)elow and not above, a patent 

 tul)ular process of peritoneum will lead down as far as the top of the testis. Any 

 liernia into this process is called a hernia into the funicular process. 



Inguinal hernia in the female. — The inguinal canal in women is smaller and 

 narrower than in men. Inguinal hernia is, therefore, uncommon in the female sex, 

 and only occurs before adolescence, in patients who happen to be the subjects of an 

 unobliterated processus funiculo-vaginalis, which extends for a varying distance 

 along the round ligament, and is called the canal of Nuck. Inguinal hernia in the 

 female is, therefore, always congenital. It is, practically, always of the oblique 

 variety, and travels along the round ligament towards the labium majus. Its cov- 

 erings will be the same as those of the oblique variety in the male, save that the 

 cremaster, as a distinct muscle, is absent, and any fibres of the internal oblique 

 which may be present are but little developed. 



Causes of hernia. — It will he well, while the anatomy of hernia is being con- 

 sidered, to refer briefiy to the causes, as many of these are intimately bound up 

 with the anatomy of the parts. Amongst the chief are the following: — 



(1) Hereditary, viz. weakness of alxlominal wall; openness of rings. 



(2) Weak spots. — (a) The presence of the cord; (b) deficiency of some of the 



