ANATOMY OF THE PERINEUM. 201 



The EXTERNAL ILIAC ARTERY, with its accompanying 

 vein, lies along the inner border of the psoas muscle ; it 

 has no branches till it reaches Poupart's ligament, where 

 it gives off two, and sometimes three. About half an inch 

 outside the artery as it passes under Poupart's ligament, 

 the crural nerve may be seen, lying deep between the psoas 

 and iliacus muscles. 



The epigastric artery has been already noticed (p. 167), but may 

 now be more particularly observed as to its origin from the external 

 iliac ; this is usually close to Poupart's ligament, but it may be found 

 at a very considerable distance either above or below it ; it frequently 

 furnishes the obturator artery. 



The circAimflexa iJii artery arises from the outer side of the artery, 



and winds along Poupart's ligament, and the crest of the ilium ; it 



ies between the internal oblique and transversalis muscles, and 



reaks up into numerous branches, some of which supply the muscles, 



while others inosculate with the ilio-lumbar artery, a branch of the 



internal iliac ; these anastomoses principally take place beneath the 



iliacus muscle, and if that be divided and detached from the ilium, 



they will be brought into view. 



The obturator artery nominally arises from the internal iliac, but in 

 a certain number of cases it arises from the external iliac by an inde- 

 pendent origin, or by a trunk common to it and the epigastric ; it 

 then descends to reach the upper and inner part of the obturator 

 foramen, and passes out through an opening in the obturator mem- 

 brane, to be distributed outside the pelvis : as it perforates this mem- 

 brane it is often joined by a small branch given off from the internal 

 iliac, which preserves the normal origin and course of the artery. 



It will be desirable at this period to turn the subject 

 over. If the previous dissections have been accomplished, 

 this can be done without embarrassing those engaged upon 

 the lower extremity. The parts connected with the region 

 of the back will be found described in Part Second, Dis- 

 section Y. 



DISSECTION Y. 



ANATOMY OP THE PERINEUM. 



As the dissection of the perineum interferes with that of other 

 parts of the body, it should consequently be made in common, the 

 dissectors mutually agreeing to suspend operations until it is accom- 

 plished. It can be done advantageously only on the male subject; 

 the peculiarities of the female perineum will be found at p. 205. 



