(\i ANIMAL CASTBATION. 



Inguinal trad or space. — It is the space between the 

 small oblique and the crural arch; oblique from up- 

 wards downwards, outwards inwards and from for- 

 wards backwards, it presents for consideration two 

 walls, two commissures, one entrance, one bottom or 

 summit. 



The anterior ivall or antero-internal is formed by 

 the small oblique muscle, which is gradually dimin- 

 ishing in thickness towards the median line and the 

 internal commissure. The posterior or postero- 

 external wall is formed by the crural arch, which is 

 quite thick inferiorly and towards the external com- 

 missure ; it is thin towards its superior border, 

 which mingles with the lumbo-iliac aponeurosis. 



The external commissure, oblique downwards, back- 

 wards and inwards, is formed by the union of the 

 muscle with the crural arch. On its entire length, 

 these two parts are adherent a little more than in the 

 tract itself, but this is no better defined outwards ; 

 this commissure can readily be forced through with 

 the fingers and the muscle isolated over a wider 

 surface from the aponeurosis which covers it. The 

 internal commissure is formed by the same parts '• 

 towards the inferior inguinal ring, by the union and 

 weak adhesion of the aponeurosis of the small 

 oblique to the arch ; higher up, by that of the pos- 

 terior border of the muscle to the superior of the 

 arch. Bent from upwards downwards and from out- 

 wards inwards, following a line running from the ilial 

 insertion of the small oblique to the prepubic tendon, 

 this commissure is still less resisting than the 



