282 ILIAC FASCIA. PELVIC FASCIA. 



^ Direct inguinal hernia d^ffgrs from oblique in never attaining the 

 same bulk, in consequence of the resisting nature of the conjoined 

 tendon of the internal oblique and transversalis and of the transversalis 

 fascia ; in its direction, having a tendency to protrude from the 

 middle line rather than towards it. Thirdly, in making for itself a 

 >"\~ new passage through the abdominal parietes, instead of following a 

 natural channel ; and fourthly, in the relation of the neck of its sac 

 to the epigastric artery; that vessel lying to the outer side of the 

 opening of the sac of direct hernia, and to the inner side of that of 

 oblique hernia. 



All the forms of inguinal hernia are designated scrotal, when they 

 have descended into that cavity. 



The FASCIA ILIACA is the aponeurotic investment of the psoas and 

 iliacus muscles ; and, like the fascia transversalis, is thick below, and 

 becomes gradually thinner as it ascends. It is attached superiorly along 

 the edge of the psoas, to the anterior lamella of the aponeurosis of the 

 transversalis muscle, to the ligamentum arcuatum intermim, and to the 

 bodies of the lumbar vertebrae, leaving arches corresponding with the 

 constricted portions of the vertebrae for the passage of the lumbar 

 vessels. Lower down it passes beneath the external iliac vessels, and 

 is attached along the margin of the true pelvis ; externally, it is con- 

 nected to the crest of the ilium ; and, inferiorly, to the outer two-thirds 

 of Poupart's ligament, where it is continuous with the fascia trans- 

 versalis. Passing beneath Poupart's ligament, it surrounds the psoas 

 and iliacus muscles to their termination, and beneath the inner third 

 of the femoral arch forms the posterior segment of the sheath of the 

 femoral vessels. 



The FASCIA PELVICA is attached to the inner surface of the os pubis 

 and along the margin of the brim of the pelvis, where it is continuous 

 with the iliac fascia. From this extensive origin it descends into the 

 pelvis, and divides into two layers, the pelvic and obturator. 



The pefoic layer or fascia, when traced from the internal surface of 

 the os pubis near the symphysis, is seen to be reflected inwards to 

 the neck of the bladder, so as to form the anterior vesical ligaments. 

 Traced backwards, it passes between the sacral plexus of nerves and 

 the internal iliac vessels, and is attached to the anterior surface of the 

 sacrum ; and followed from the sides of the pelvis, it descends to the 

 base of the bladder and divides into three layers, one ascending, is re- 

 flected upon the side of that viscus, encloses the vesical plexus of veins, 

 and forms the lateral ligaments of the bladder. A middle layer passes 

 inwards between the base of the bladder and the upper surface of the 

 rectum, and was named by Mr. Tyrrell the recto-vesical fascia ; and an 

 inferior layer passes behind the rectum, and, with the layer of the 

 opposite side, completely invests that intestine. 



The obturator fascia passes directly downwards from the splitting 

 of the layers of the pelvic fascia, and covers in the obturator internus 

 muscle and the internal pudic vessels and nerve ; it is attached to the 

 ramus of the os pubis and ischium in front, and below to the falciform 



