no A MANUAL OF ANATOMY 



the internal and external oblique, crosses the iliac crest at the 

 junction of its middle and anterior thirds to be distributed to the 

 integument of the adjacent part of the gluteal region. The nerve 

 continues its course forwards between the internal oblique and 

 transversalis abdominis, supplying branches to these muscles and 

 communicating with the inguinal nerve. About i inch in front of 

 the anterior superior iliac spine it pierces the internal oblique, 

 and then runs forwards between the Poupart fibres of that muscle 

 and the external oblique aponeurosis. • Finally it pierces that 

 aponeurosis i inch above the external abdominal ring, and is 

 distributed to the integument of the suprapubic region, where it 

 is in series with the anterior cutaneous nerves. The ilio-hypogastric 

 nerve is serially continuous with the intercostal nerves, like which 

 it gives off a lateral cutaneous branch, called iliac, and then ends 

 as an anterior cutaneous nerve. 



The inguinal nerve (ilio-inguinal), having pierced the outer 

 border of the psoas magnus lower down than, but close to, the 

 ilio-hypogastric, passes obliquely outwards and downwards over 

 the quadratus lumborum, where it may lie below the lower end of 

 the kidney or behind it. It then passes forwards internal to the 

 inner lip of the iliac crest beneath the transversalis abdominis. In 

 this part of its course it rests upon the iliac fascia and iliacus 

 muscle. Near the anterior part of the iliac crest it pierces the 

 transversalis, and here communicates with the hypogastric branch 

 of the ilio-hypogastric. It subsequently perforates the Poupart 

 fibres of the internal oblique, after which it descends through the 

 lower two- thirds of the inguinal canal, and emerges through the 

 external abdominal ring, where it lies external to the spermatic 

 cord. Finally, having pierced the intercolumnar fascia, it is distri- 

 buted to the integument of the inner side of the thigh in its upper 

 third, and the integument of the scrotum, or labium majus, according 

 to the sex. The inguinal nerve in its course supplies branches to 

 the internal oblique and transversalis abdominis muscles. It differs 

 from the ilio-hypogastric and intercostal nerves in the following two 

 respects : it does not give off any iliac or lateral cutaneous branch, 

 and it is not distributed to the integument of the abdominal wall. 



The genito-{emoral nerve passes forwards through the psoas 

 magnus, and appears on its superficial surface about the level of 

 the body of the third lumbar vertebra, where it lies close to the 

 inner border of the muscle. It sometimes pierces the muscle in two 

 parts, due to an early division of the nerve into its genital and 

 crural branches. It then descends upon the psoas sheath, passing 

 slightly outwards, and crossing behind the ureter. At a variable 

 distance above Poupart's ligament (sometimes in the psoas magnus) 

 the nerve divides into two branches, genital and crural. The genital 

 branch lies upon the external iliac artery close above Poupart's 

 ligament, and enters the inguinal canal through the internal 

 abdominal ring to be distributed to the cremaster muscle. The 

 crural branch descends on the outer side of the external iliac artery 



