378 SURGICAL APPLIED ANATOMY. [Chap. xvm. 



with hardened faeces. From this apathy it has pro- 

 bably happened that, in the self-administration of 

 enemata, patients have thrust the tube through the 

 rectum into the peritoneal cavity. The last two 

 inches of the bowel, on the other hand, are extremely 

 sensitive. 



The pain at the end of the penis felt in prostatic 

 affections, and in stone, or other maladies involving 

 the bladder neck, is probably explained by the fact 

 that the prostatic nerve plexus (that supplies both 

 the gland and the neck of the bladder) is continued 

 to the end of the penis as the cavernous plexus. It 

 terminates at the very spot where the penile pain is 

 mostly complained of, viz., at the posterior part of the 

 glans. 



The nerve relations between the anus and the neck 

 of the bladder are very intimate. Painful affections of 

 the anus often cause bladder troubles, and retention 

 of urine is very common after operations upon piles. 

 Maladies, on the other hand, that involve the bladder 

 neck are often associated with tenesmus and anal dis- 

 comfort. This relation is maintained by the pelvic 

 plexus, but mainly by the fourth sacral nerve. This 

 nerve gives special branches direct to the neck 

 of the bladder, and then goes to supply the muscles of 

 the anus (the sphincter and levator) and the integu- 

 ment between the anus and the coccyx. 



The mucous membrane of the urethra, the muscles 

 of the penis, and the greater part of the skin of the 

 penis, scrotum, perineum, and anus, are supplied by the 

 pudic nerve. Thus, it will be understood that irritation 

 applied to the urethra may cause erection of the penis 

 (as illustrated by chordee in gonorrhoea), or may pro- 

 duce contraction of the urethral muscles (as seen in 

 some forms of spasmodic stricture). The disturbance 

 caused by accumulated secretion beneath the prepuce 

 in young children may provoke great irritability of the 



