Iliac Fascia 307 



As the transversalis fascia completely lines the antero-lateral 

 aspect of the abdominal cavity, no hernia can escape thence without 

 deriving a covering from it. The femoral variety takes an investment 

 from it under the name of the anterior layer of the crural sheath ; 

 the oblique inguinal hernia is, like the cord, invested by the infundi- 

 buliform process, and direct inguinal and umbilical herniae derive 

 special investments from it. 



The coverings of an oblique inguinal hernia are, then, skin, two 

 layers of superficial fascia, intercolumnar fascia (of external oblique), 

 cremasteric fascia (of internal oblique), infundibuliform fascia, sub- 

 peritoneal fat, and the sac. In the female an oblique inguinal, labial 

 hernia may enter the labium pudendi ; it has the same coverings as a 

 scrotal hernia, except that there may be no representative of cremas- 

 teric fascia. 



The iliac fascia is a strong investment for the iliacus and psoas ; 

 it is beneath the iliac vessels, and is connected above with the internal 

 arcuate ligament. Internally it is attached to the vertebral column 

 and to the brim of the true pelvis ; externally it meets the transversalis 

 fascia at the iliac crest and along the outer half of Poupart's ligament. 

 Passing down beneath the external iliac vessels, it forms the posterior 

 layer of the crural sheath, and on the inner side of them it joins the 

 transversalis fascia at Gimbernat's ligament. The branches of the 

 lumbar plexus are beneath it. (For crural sheath see p. 313.) 



The iliacus arises from the iliac fossa and ilio-lumbar ligament, 

 and slightly from the capsule of the hip-joint, over which it passes to 

 its insertion into the tendon of the psoas and into the femur below it. It 

 flexes, adducts, and everts the thigh. It is closely covered in by the 

 iliac fascia and has in front the external cutaneous nerve, peritoneum, 

 caecum or sigmoid flexure (according to side), and, more internally, 

 the psoas and anterior crural nerve. It passes under Poupart's 

 ligament, a bursa intervening between it and the hip-joint. Lower 

 down, it is covered by the fascia lata, sartorius, and deep femoral 

 vessels. 



The psoas arises from the bodies and transverse processes of the 

 last dorsal and the lumbar vertebrae, and from the intervening discs. 

 Its upper end extends beneath the internal arcuate ligament ; it 

 descends below Poupart's ligament and is inserted into the lesser 

 trochanter. Its action resembles that of the iliacus, but, in addition, 

 it acts upon the lumbar spine. 



It is invested by the iliac fascia, and in its substance is the lumbar 

 plexus the ilio-hypogastric, ilio-inguinal, and external cutaneous 

 emerge along its outer side, the genito-crural pierces it in front, the 

 obturator lies along its inner border, and the anterior crural is em- 

 bedded between it and the iliacus, which is on its outer and posterior 

 aspect. The vena cava, on the right, and the aorta, on the left, and, 

 lower down, the common iliac vessels, lie along its inner border. 



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