chap, xviii.] THE URETHRA. 361 



the orifice of the urethra. If the affection be general, 

 the prostatic urethra is lengthened, and if one lateral 

 lobe be more enlarged than the other, the canal 

 deviates to one side. When the enlargement par- 

 ticularly affects the middle lobe, the prostatic urethra, 

 which is normally almost straight, becomes con- 

 siderably curved, the curve being sometimes very 

 abrupt. 



It is important to note that enlargement of the 

 middle lobe alone can hardly be made out by rectal 

 examination. 



Between the prostate and its capsule is an exten- 

 sive plexus of veins, the prostatic plexus, into which 

 enters the dorsal vein of the penis. Phlebolithes are 

 said to be more frequently met with in these veins 

 than in any other in the body. This plexus is cut in 

 lateral lithotomy, and it is through its vessels that 

 septic matter is probably absorbed in cases of pysemia 

 following that operation. 



The male urethra is about eight and a half 

 inches in length, an inch and a quarter being devoted 

 to the prostatic urethra, three-quarters of an inch 

 to the membranous, and six and a half inches to 

 the penile or spongy portion. The canal may be 

 divided into a fixed and a movable part. The 

 fixed part extends from the neck of the bladder to the 

 posterior extremity of the penile urethra at the .point 

 of attachment of the suspensory ligament. The fixed 

 part describes an even curve, fairly represented by 

 the line of a " short-curve " metal catheter. The 

 two ends of the curve lie about in the same line, viz., 

 one drawn across the lower end of the symphysis, 

 and at right angles to the vertical axis of that arti- 

 culation. The curve is formed around this line, its 

 summit corresponding to a prolongation of the vertical 

 axis of the symphysis, and to about the centre of the 

 membranous urethra. This part of the tube lies 



