ABDOMEN. 



13 



consider this as merely a portion of the subperi- 

 toneal cellular tissue, but I cannot help regard- 

 ing it as a process from the iliac fascia itself to 

 envelope the vessels just as that fascia envelopes 

 the circumflexa ilii artery between two lamina 

 at its outer margin. I have never seen an in- 

 stance in which this sheath was not perfectly dis- 

 tinct, in some cases it is of considerable strength, 

 but in the majority weak and transparent. It 

 was this slveath which impeded Mr. Abernethy 

 in one of his earliest operations for applying a 

 ligature to the external iliac artery.* 



The connexion which the iliac fascia has 

 with the fascia transversalis at the crural arch, 

 and the relation both bear to the iliac vessels at 

 their exit to become femoral, suggested to Mr. 

 Colles a comparison which is constantly referred 

 to by anatomists. " It may be said to resem- 

 ble," he says, " a funnel, the wide part or 

 mouth of which occupies the hollow of the 

 ilium and lower part of the abdominal muscles, 

 and the narrow part or pipe of which passes 

 downwards on the thigh. The mouth of this 

 funnel may be supposed to rise as high as the 

 upper edge of the iliac muscle, and to be turned 

 toward the cavity of the abdomen : the pipe 

 joins the wide part where the external iliac 

 vessels are passing under Poupart's ligament, 

 and it is continued down on the thigh, so low 

 as to reach the insertion of the saphena into the 

 femoral vein."f 



From the preceding sections it appears that 

 a fibro-cellular expansion lines the whole in- 

 ternal surface of the abdominal parietes. It is 

 so likewise with the pelvis, and also with the 

 thorax. The cavity of the cranium, too, is 

 lined with a fibrous membrane,, although of a 

 different nature, and doubtless performing a dif- 

 ferent office. 



5. Between the internal fibrous expan- 

 sion of the abdomen and the peritoneum is 

 a cellular tissue, which presents different cha- 

 racters in each region ; it is the subperitoneal 

 cellular tissue. Along the anterior wall it is 

 thin and fine, except inferiorly opposite the in- 

 ternal abdominal ring, where it becomes more 

 abundant, as well as in the hypogastric region, 

 immediately above the pubis. In the iliac 

 fossa and lumbar region it is lax and abundant, 

 especially in the latter, where there is also a 

 considerable quantity of fat surrounding the 

 kidney. In the iliac fossa this cellular tissue 

 is stretched across the crural ring, and forms 

 what Cloquet describes under the name of 

 septum crurale. On the superior wall it is ex- 

 tremely fine, and in very small quantity. Im- 

 mediately behind the sternum, and in the mid- 

 dle line, this cellular tissue communicates with 

 that of the mediastinum through a separation 

 of the anterior fibres of the diaphragm. 



This subserous cellular tissue forms the pri- 

 mary covering of all herniae, which push a 

 peritoneal sac before them, and as being the 

 fascia constituting the nearest investment of the 

 sac, it is generally called the fascia propria. 



* Abernethy's Surgical Works, vol. i. p. 225. 

 t Colics' Surgical Anatomy, pp. 68, 69. 



Opposite the crural canal this cellular tissue is 

 often so abundant, as, when condensed by the 

 pressure of the hernial tumour, to form an ex- 

 pansion over the sac of considerable thickness. 

 Sometimes it contains fat, and not unfrequently 

 we find a large lymphatic ganglion in it, filling 

 up the crural ring. 



6. Peritoneum. A considerable part of the 

 abdominal surface of the walls of the abdomen 

 is lined by a very fine transparent serous mem- 

 brane the peritoneum, which is likewise con- 

 nected, to a greater or less extent, with every 

 viscus within the cavity. In consequence of 

 this double connexion, it happens that in various 

 situations the peritoneum is reflected from the 

 wall of the abdomen upon an adjacent viscus, 

 and thus are produced various folds of this mem- 

 brane, which demand the attention of the ana- 

 tomist. These folds are rendered distinct when 

 such a section of the anterior abdominal wall is 

 made as without dividing them to allow of it 

 being held apart from the viscera. I shall 

 enumerate these folds in describing the relation 

 of the peritoneum to the several walls. The 

 anterior wall of the abdomen is entirely lined 

 by peritoneum, and has in connexion with it 

 four folds, all of which, as it were, radiate from 

 the umbilicus. In the adult these folds are 

 reflected round four ligamentous cords (three 

 of which are the remains of bloodvessels in 

 the foetus), which meet at the umbilicus and 

 diverge, one upwards, backwards, and to the 

 right side (the obliterated umbilical vein), 

 two downwards and outwards towards Pou- 

 part's ligament on each side, so as to pass 

 behind the inguinal canal, nearly midway 

 between the two rings (the obliterated um- 

 bilical arteries), and the fourth nearly ver- 

 tically downwards along the middle line to be 

 inserted into the apex of the bladder (the ura- 

 chus). The four folds are similar in direction 

 to that of the fibrous cords contained within 

 them : the fold which passes upwards towards 

 the liver is falciform, the concavity being di- 

 rected downwards and backwards. From its 

 connexion with the convex surface of the liver 

 it is also called the falciform ligament of the 

 liver, and the fibrous cord contained in its in- 

 ferior margin, the ligamentum teres. The in- 

 ferior and external folds pass each from 

 the umbilicus, downwards and outwards to 

 the iliac fossa, to a point a little on the inner 

 side of the internal abdominal ring, where it dis- 

 appears, being continued externally over the 

 iliac fossa, and internally behind the rectus 

 muscle. This fold, when stretched towards 

 the umbilicus, evidently forms the partition 

 between two pouches, the external and in- 

 ternal inguinal pouches, which correspond re- 

 spectively to the internal and external abdo- 

 minal rings, and indicate the situations at 

 which make their escape those two forms 

 of inguinal hernia, which, from their connexion 

 with these pouches, are called by Hesselbach 

 external and internal inguinal hernias ; the for- 

 mer being that by oblique descent, the latter 

 that by direct descent. 



The fourth or vertical fold indicates the 



