13 72 THE VRINOGEXITAL ORGANS 



low to very considerably modify the operation of lithotrity and introduce that of litholapaxy. 

 In passing a fine catheter, the point of the instrument after it has passed the lacuna magna should 

 be kept as far as possible along the upper wall of the canal, as the point is otherwise very liable 

 to enter one of the lacunae. Stricture of the urethra is a disease of very common occurrence, and 

 is generally situated in the spongy portion of the urethra, most commonly in the bulbous portion 

 just in front of the membranous urethra, but in a very considerable number of cases in the penile 

 part of the canal. Even in a normal urethra, and very markedly in an inflamed urethra, a 

 bougie encounters resistance behind the bulb. This is usually supposed to be due to spasm of 

 the Compressor urethrse muscle. 



In irrigation of the urethra by gravity fluid tends to block at the same point, especially if it is 

 thrown in suddenly or forcibly. If a reservoir is raised seven ahd one-half feet from the floor, 

 and if a patient sits on a chair or lies upon a bed, fluid can be readily made to pass by hydraulic 

 pressure from the meatus to the bladder. Spasm may temporarily prevent the inflow, but the 

 weight of the column of fluid soon tires out the muscle and causes it to relax. Relaxation is 

 favored by having the patient take slow, deep breaths, and make efforts at urination (Valentine). 



Chronic gonorrhea is frequently kept up by persistent inflammation of the ducts and follicles 

 in the mucous membrane. This condition is known as chronic glandular urethritis or para- 

 urethritis. In these crypts and glands gonococci may remain when gonorrhea appears to have 

 passed away, and from time to time reinfection of the urethra may arise from such a source. 



Median urethrotomy or perinea!, section is opening of the membranous urethra. Through such 

 an opening the bladder can be drained and explored, and the operation is sometimes called 

 median cystotomy. 



In lateral lithotomy the knife enters the membranous urethra and strikes the groove of the 

 staff. Its edge is then turned toward the left ischial tuberosity and is carried along the groove 

 into the bladder, dividing the membranous urethra, the prostatic urethra, the posterior layer of 

 the triangular ligament, the Compressor urethra? muscle, anterior fibres of the Levator ani 

 muscle and the left lobe of the prostate gland. 



THE FEMALE URETHRA (URETHRA MULIEBRIS). 



The female urethra is a narrow membranous canal, about an inch and a half in 

 length, extending from the internal urethral orifice at the neck of the bladder to 

 the meatus urinarius. It is placed behind the symphysis pubis, embedded in the 

 anterior wall of the vagina, and its direction is obliquely downward and forward; 

 its course is slightly curved and the concavity directed forward and upward. 

 Ordinarily the wall is collapsed so that the lumen is of stellate outline; the urethra 

 may be dilated to about a quarter of an inch (6 to 8 mm.); toward the bladder 

 the calibre increases slightly. The urethra perforates both layers of the tri- 

 angular ligament, and its external orifice is situated directly in front of the vaginal 

 opening and about an inch behind the glans clitoridis. 



Structure. The female urethra consists of three coats mucous, muscular, and fibrous. 



The mucous coat (tunica mucosa) is pale, continuous externally with that of the vulva, and 

 internally with that of the bladder. It is thrown into longitudinal folds, one of which, placed 

 along the floor of the canal, extends from the vesical trigone almost to the external orifice of the 

 urethra. It is called the crest (crista urethralis). The outline of the urethra is stellate when 

 collapsed, because of the formation of numerous longitudinal folds. It is lined by laminated 

 epithelium, which becomes transitional near the bladder. Many mucous glands open into the 

 urethra, and there are numerous lacunae. On either side of the terminal portion of the urethra 

 lie a group of mucous glands (glandulae paraurethrales) , each lateral group opening into the vesti- 

 bule by a common duct (ductus paraurethralis) at the side of the urinary meatus. These glands 

 are regarded as being homologous with the prostate in the male. 



The mucous coat is lined by stratified squamous cells resting upon a basement membrane and 

 by papillated tunica propria; the latter consists of fibroelastic tissue containing the smaller 

 vessels, some lymphoid tissue, and a few racemose glands. In the deeper portion of the tunica 

 propria the structure is very vascular, is of a spongy nature, and constitutes the erectile tissue. 



The muscular coat (tunica muscularis) is continuous with that of the bladder; it extends the 

 whole length of the tube, and consists of an internal layer of nonstriated longitudinal fibres 

 (stratum Jongitudinale) and an external layer of nonstriated circular fibres (stratum circulare). 

 In addition to these, between the two layers of the triangular ligament, the female urethra is sur- 

 rounded by the Compressor urethras muscle, as in the male. 



