408 SURGICAL APPLIED ANATOMY. [Chap. xvm. 



happens, therefore, that when Hunterian chancreg 

 appear on this part they can never be associated with 

 other than the most trifling induration, there being no 

 tissue in which the thickening can develop. At tho 

 corona, on the other hand, the submucous tissue is 

 lax and plentiful, so that the induration can readily 

 form, and it is about this spot, therefore, that the 

 syphilitic sore attains often its most characteristic 

 development. The vascularity of the penis, and the 

 rapid engorgement that ensues when the return of its 

 venous blood is impeded, serve to explain the ready 

 and extensive swelling of the organ that follows when 

 any constricting baud is placed about it. This should 

 be borne in mind in tying in a catheter by securing it 

 by tapes around the penis. The penis is often the 

 seat of arrests of development, presenting a variety 

 of appearances. Among them may be mentioned 

 Jiypospadias, where the inferior wall of the urethra 

 and corresponding part of the corpus spongiosurn 

 are wanting, and epispadias, where the superior wall 

 of the canal and corresponding parts of the corpora 

 cavernosa are more or less entirely deficient. 



Scrotum. The skin of the scrotum is thin and 

 transparent, so that in bruising of the parts the dis- 

 coloration due to the extravasation of blood beneath 

 the surface is readily and distinctly seen. It is also 

 very elastic, and allows of great distension, as is seen 

 in large scrotal hernise and testicular tumours. The 

 integument of the part is indeed redundant, and the 

 excision of a portion of it will hardly be missed. Even 

 in gangrene of the scrotum, when both testicles have 

 been exposed, the parts have been entirely restored 

 without any inconvenient shrinking or contraction. 

 The rugae on the surface of the scrotum favour the 

 accumulation of dirt, and the irritation set up by such 

 accumulation may be the exciting cause of the epi- 

 theliomata that are not uncommon in this part When 



