The Perineum. 295 



the inferior hemorrhoidal nerve are not limited to the 

 sphincter ani muscle, since the inferior hemorrhoidal is a 

 branch of the pudic, and the pudic is derived from the 

 third and fourth sacral nerves, and, since these nerves 

 send branches to the viscera of the pelvis to communicate 

 with the sympathetic system, it follows, that irritation of 

 the inferior hemorrhoidal nerves may be transferred to the 

 bladder and induce vesical tenesmus, or retention of urine, 

 as seen after operations on the anus, or, it may be trans- 

 ferred to the penis, through the pudic itself, thus causing 

 pain in the integument of the penis, or priapism, or neu- 

 ralgia of the urethra. The pain that is sometimes felt 

 down the inner and back parts of the thigh, or, in the 

 perineum, from affections of the anus, rectum, prostate or 

 bladder, depends on the fact that, while the third and fourth 

 sacral nerves give branches, as above mentioned, to the 

 pelvic viscera, the third helps to form the sciatic, and 

 the fourth forms the pudic, hence, in inflammatory affec- 

 tions of these organs the pain may be referred to the dis- 

 tribution of the sciatic, i.e., to the inner and back parts of 

 the leg, or to that of the pudic, i.e., the perineum and 

 penis. In ischio-rectal abscess, reflex disturbances affect- 

 ing the bladder and rectum may follow similar paths, and 

 in this disease, the inferior pudendal, a branch of the small 

 sciatic, is especially involved, so that the pain is readily 

 reflected to the other branches of this nerve in the leg. 



Stone in the bladder may cause retraction of the tes- 

 ticle, or erection of the penis, or pain, felt in the penis, or 

 at its end. In the first case, i.e., when retraction of the 

 testicle is present, the stone generally rests on the trigone, 

 which is richly supplied with branches from the inferior 

 hypogastric plexus, but this plexus sends branches to the 

 vas deferens, which communicate with the spermatic 

 plexus. Hence, irritation of these plexuses, surround- 



