- 
the fascia propria is derived from the fascia transversalis of Hesselbach’s triangle. 
The extra-peritoneal fat which covers the outer surface of the hernial sac is some- 
times hypertrophied to such an extent as to amount to a fatty tumour. 
In a large proportion of children at birth the funicular process of peritoneum, 
which connects the tunica vaginalis testis with the abdominal peritoneum, 
especially on the right side, is still patent. . Should the bowel force its way 
along the patent process a congenital inguinal hernia arises. In the majority of 
the cases of congenital inguinal hernia it will be found that the tunica vaginalis 
testis has been shut off by closure of the lower part of the funicular process, only 
the upper part remaining patent and forming the sac of the hernia. In regard to 
the operation for the cure of inguinal hernia, it should be borne in mind that in 
the acquired form the hernia produces the suc, whereas in the congenital variety 
the sae is the cause of the hernia; it follows, therefore, that im the operation for 
acquired hernia the closure of the canal is as important as the removal or oblitera- 
tion of the sac, while in a congenital hernia the most essential part of the operation 
is the closure of the neck of the sac, and as the muscular and fascial apparatus 
forming the walls of the canal are well developed, they should be interfered with 
as little as possible. A patent funicular process may persist durmg adult life 
without any bowel descending into it; on the other hand, years after birth bowel 
may suddenly enter it. In practically all oblique inguinal herniz, which develop 
suddenly in children as well as in adolescents and young adults, the sae is of 
congenital origin. 
Parallel to and at the level of the outer half of Poupart’s ligament is the deep 
circumflex iliac artery. In dividing the abdominal wall to reach the structures in 
the iliac fossee, the incision should be made in the angle between this vessel and the 
deep epigastric artery. To lessen the risk of ventral hernia the muscles should be 
split in the direction of their fibres—the aponeurosis of the external oblique from 
above downwards and inwards, the muscular fibres of the internal oblique and 
transversalis horizontally. An incision through the abdominal wall parallel to the 
outer border of the rectus has the great disadvantage of dividing the abdominal 
terminations of the lower intercostal nerves, which run parallel to a line extending 
from the tenth costal cartilage to the umbilicus. 
The middle line is the site usually selected by the surgeon to open the abdomen. 
The points of surgical importance to be noted in connexion with the linea alba are : 
(1) that its blood supply is scanty; (2) that it is considerably wider above than 
below the umbilicus, where the two ee of the recti he in close apposition ; (3) 
that above the umbilicus the fascia transversalis and linea alba are. adherent, so 
that the two form practically one membrane; (4) that the extra-peritoneal fat is more 
abundant beneath the linea alba than to either side of it; (5) that above the pubes 
the fascia transversalis recedes from the lnea alba, leaving a triangular space 
occupied by fat which must not be mistaken-for the extra-peritoneal fat. 
The posterior layer of the rectal sheath ceases at the fold of Douglas, which is 
situated one-third of the distance from the umbilicus to the pubes. The fleshy 
fibres of the transversalis muscles extend inwards for a considerable distance 
behind the upper part of the recti. 
THE ABDOMINAL CAVITY. 1221 
THE ABDOMINAL CAVITY. 
To simplify the topography of the abdominal viscera the abdomen is arbitrarily 
divided into nine regions by two horizontal and two vertical planes. Of the two 
horizontal planes, the upper (infracostal) plane is at the level of the lowest part of 
the tenth costal cartilages; the lower (intertubercular) plane is at the level of the 
tubercular points of the iliac crests. The two vertical planes correspond upon the 
surface to a line drawn vertically upwards on either side from a poimt midway 
between the anterior.superior iliac spine and the pubic symphysis. Superiorly, 
these vertical planes generally strike the tip of the ninth costal cartilages. The 
subdivisions of the upper zone are termed the epigastric and right and left hypo- 
chondriac regions, of the middle zone the wmbilical and right and left lumbar regions, 
of the lower zone the /ypogastric and right and left iliae regions. The epigastric, 
= 
