268 FASCIA ILIACA FASCIA PELVICA. 



of the hernia passing into the scrotum, behind the tunica vaginalis. So 

 that the surgeon in operating upon this variety, requires to divide three 

 layers of serous membrane ; the first and second layers being those of the 

 tunica vaginalis ; and the third the true sac of the hernia. 



DIRECT INGUINAL HERNIA has received its name from passing directly 

 through the external abdominal ring, and forcing before it the opposing 

 parietes. This portion of the wall of the abdomen is strengthened by the 

 conjoined tendon of the internal oblique and transversalis muscle, which 

 is pressed before the hernia, and forms one of its investments. Its cover 

 ings are, the 



Integument, Conjoined tendon, 



Superficial fascia, Transversalis fascia, 



Intercolumnar fascia, Peritoneal sac. 



Direct inguinal hernia differs 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 di- 

 rection, having a tendency to protrude from the middle line rather than 

 towards it. Thirdly, in making for itself a new passage through the ab- 

 dominal 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 internum, 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 connected to the crest of the ilium ; 

 and, inferiority, to the outer two-thirds of Poupart's ligament, where it is 

 continuous with the fascia transversalis. Passing beneath Poupart's liga- 

 ment, 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 pel- 

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



The pelvic layer OT 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 reflected upon the side of 

 that viscus, encloses the vesical plexus of veins, and forms the lateral liga- 

 ments of the bladder. A middle layer passes inwards between the base 



