'/'///; U'MliAK PLEXUS 



987 



nerve. A short distance below the anterior superior spine it passes through the in- 

 ternal oblique muscle, anil then descends in the inguinal canal to the subcutaneous 

 inguinal (external abdominal) ring, through which it emerges into the thigh on the 

 outer side of ! he spermatic cord (fig. <>,S(>). It is distributed to the skin of the upper 

 and inner part of the. thigh, in t he male to t he root of the pen is and I" t he skin of t he 

 root of the scrotum through \\*>. anterior scrotal nerves (iig. 01)1), and in the 

 female 1 to the mons veneris and labium majus through the anterior labial nerves. 

 Not uncommonly the ilio-inguinal nerve is blended with the ilio-hypogustric nerve 



Fio. 687. DIAGRAM OF A COMMON FORM OF LUMBO-SACRAL PLEXUS. (Modified 



Paterson.) 



FROM LAST TJ/OJIA ric Ml; I /; 



QSNTTO-FEltORAL 



II.HI-/IYI-III; \sn:n ---- 



FIRST Ll'XBAR 



--- SECOSJI i.i .VH.II: 



T11IR1I LfMBAR 



FOfRTII LfMBAR 



LATERAL Cl 



r.i\i-;ii< S 

 OBTURATOR -... 



ACCESSORY .. 



iiiii'ri:.ii'ii/: 



TOTLTACOSAND <' 



I'M US MAJOR 



FIFTH SACRAL 



TII i'i>i'i-Yi;l-:fs 



TO I.EVATur. AM 

 COCCYGKAL 



EXTERNAL 



1'nl'i.i 1 1 i / 



INTKR'SAL 



POPLITEAL 



SttCTIOfi 



VM I I I '/ I TIC PEKFORATIKC 



SMALL 81 /.I //' ci-TAXEors 



ASo-i'OCCYGEAL 



from 



TO OBTURATOR I\TI'I! \I'S 



and separates from the latter between the transversus abdominis and the internal 

 oblique muscles. It may be replaced by branches of the gemto-femoral (gemto- 



crural) nerve, or it may replace that nerve or the lateral cutaneous nerve. 



The Genito-femoral (genito-crural) Nerve is connected with the first and second 

 lumbar nerves, but the majority of its fibres are derived from the second nerve. 

 passes obliquely forwards and downwards through the psoas and emerges from t 

 anterior surface of that muscle, close to its internal border, at the level of the lower 

 border of the third lumbar vertebra. After emerging from the substance of the 



