



Inguinal Canal 309 



Small lobulated offshoots from this subserous layer are apt to pro- 

 trude through the iinea alba, and sometimes they grow into mushroom- 

 like masses which closely simulate omental hernioe. They differ from 

 omental hernia in that they are enclosed in no peritoneal sac ; but 

 this cannot be recognised until they are exposed by an incision, as in 

 an attempt to perform a radical operation for their obliteration. In 

 puerperal cellulitis inflammation spreads rapidly through the sub- 

 serous layer, and an abscess in it may open into the peritoneal cavity, 

 into an abdominal or pelvic viscus, or, passing outwards, may find 

 escape through the abdominal wall. 



Anastomosis between parietal and visceral blood-vessels. 

 In the sub-peritoneal tissue there is a delicate but general anastomosis 

 between the blood-vessels of those viscera which are on any particular 

 surface destitute of peritoneum, and those of the adjacent abdominal 

 wall. Thus, the hepatic vessels communicate with phrenic and inter- 

 costals ; renal and supra-renal with phrenic, intercostal, and lumbar ; 

 pancreatic and duodenal with phrenic and intercostal ; colic with 

 ilio-lumbar, circumflex iliac, lumbar and intercostal ; ovarian with 

 iliac ; haemorrhoidal with sacral, iliac, and pudic, and spermatic with 

 cremasteric and perineal. These important anastomoses explain the 

 value of cupping and leeching in hepatic and renal congestion, and in 

 ovaritis, epididymitis, and orchitis. 



The inguinal canal is the tunnel, \\ in. long, through which the 

 spermatic cord descends. It runs obliquely, so that there may be 

 less chance of a piece of bowel entering it in a similar manner the 

 ureter passes through the strata of the vesical wall, so that in disten- 

 sion of the bladder the sides of the passage may be pressed against 

 each other and regurgitation towards the kidney prevented. 



The upper end of the inguinal canal is the internal abdominal ring, 

 about an inch above the middle of Poupart's ligament; the lower 

 end is the external ring, on the pubic crest. As the canal follows the 

 downward course of Poupart's ligament, the internal ring is further 

 from the middle line of the body than the external. Behind the canal 

 the deep epigastric artery runs in a direction upwards and inwards. 

 The artery lies, therefore, to the outer side of the external ring (but 

 at a much deeper level), and to the inner side of the internal ring, as 

 shown on p. 306. 



Boundaries of the canat.The floor is formed by Poupart's liga- 

 ment and the pubic crest. Posteriorly is the conjoined tendon. 

 Above are the arched border of the transversalis muscle and the 

 lower part of the internal oblique. In front are cremasteric and inter- 

 columnar fascise. Loosely investing the cord is the funnel-shaped 

 process of the transversalis fascia, which thus lines the canal. 



