THE MALE PERINEUM. 201 



nalis, the result of the descent of that organ into the 

 scrotum. That portion of the peritoneum which is thus 

 cut off from the bag, remains as a shut sac, investing the 

 outer surface of the testis (tunica vag. testis), and is re- 

 flected on to the scrotum (tunica vag. reflexa). Collec- 

 tions of fluid (hydrocele, hcematocele) are thus related to 

 the testis namely, that they are above and in front of 

 it, unless there be any abnormality, such as an inversion 

 of the testis. In removal of the testis (castration), the 

 retraction of the cord into the abdominal cavity, owing 

 to the action of the cremaster muscle, is liable to give 

 trouble, unless it be firmly secured. 



The structures divided in the operation of castration 

 would be as follows: (1) the scrotal tissues, with the 

 vascular and nervous supply viz., the superficial peri- 

 neal vessels and nerves, inferior pudendal nerve, super- 

 ficial external pudic vessels ; (2) the structures entering 

 into the formation of the cord. 



SURGICAL ANATOMY OF THE MALE PERINEUM. 



This region is to be studied when the body is placed 

 in what is known as the lithotomy position that is, 

 with the legs flexed on the thighs, and the thighs on the 

 pelvis, in order that the parts to be examined be on the 

 stretch. 



In the erect position the superficial aspect of the re- 

 gion becomes a mere fold. 



There is considerable difference in the descriptions 

 given by authors as to what the limits of the perineum 

 really are: some including all those structures which 

 close in the inferior outlet of the pelvis, its entire floor 

 in fact ; others dividing this lozenge-shaped space into 



