THE URINARY BLADDER 1249 



and then forward and downward upon the obturator internus and its fascia 

 behind and below the psoas, crossing the obturator vessels and nerve and having 

 anterior to it in the female the posterior border of the ovary. It thus reaches the 

 level of the floor of the peritoneal cavity, whereupon, at about the level of the 

 ischial spine, its course is directed forward and medially toward the bladder. 

 In this part of its course in the m,ale, it is crossed superiorly and medially by the 

 ductus deferens, and then passes under cover of the free extremity of the vesicula 

 seminalis, separated from its fellow by a distance of 37 mm. In the female it 

 runs parallel with, and 8 to 12 mm. distant from, the cervix uteri, passes behind 

 the uterine artery, through the uterine plexus of veins, and beneath the root of 

 the broad ligament, and finally crosses the upper third of the lateral wall of the 

 vagina to reach the vesico-vaginal interspace and enter the substance of the 

 bladder at about the junction of its posterior, superior and lateral surfaces. 



The vesical portion, about 12 mm. in length, runs obliquely downward and 

 medialward through the coats of the bladder, and opens on its mucous surface 

 about 20 to 25 mm. from both its fellow and the internal urethral orifice. 



Structure. — The wall of the ureter is about 1 mm. (jV in.) in thickness, and consists of a 

 mucous membrane, a muscular coat, and an external connective-tissue investment. The mucous 

 membrane is longitudinally plicated, and is Uned by transitional epithelium, continuous with 

 that of the papillae above and with that of the bladder below. Mucous foUicles of simple form 

 have been found in the upper part of the canal. The muscularis is about 0.5 mm. (1/50 in.) in 

 thickness, and consists of two layers, an external, composed of annular fibres, and an internal, 



Fig. 1012. — Pelvis and Upper Portion of Ureter. (After Henle.) 



Calyx minor 



Infundibulum 



Superior calyx major 



Pelvis Ji" ^% ^Pftoj J Calyx minor 



Ureter 



Inferior calyx major 



of fibres longitudinally disposed. After the tube has entered the bladder the circular fibres form 

 a kind of sphincter around its vesical orifice; while the longitudinal fibres are continued onward 

 through the wall of the bladder and terminate beneath its mucous membrane. 



Vessels and nerves. — The arteries supplying the pelvis and upper part of the ureter come 

 from the renal; the rest of the abdominal portion of the ureter is supplied by the spermatic 

 (or ovarian), and its pelvic portion receives branches from the middle hsemorrhoidal and in- 

 ferior vesical; the veins terminate in the corresponding trunks; and the lymphatics pass to the 

 lumbar and hypogastric nodes. The nerves are supplied by the spermatic, renal, and hypo- 

 gastric plexuses. 



Variations. — Occasionally the depression which separates the two calyces majores extends 

 through the pelvis, so that the calyces appear to open directly into the ureter. The fission may 

 also affect the lu-eter to a greater or less extent, in extreme cases producing a duplication of 

 the tube throughout its entire length. 



THE URINARY BLADDER 



The urinary bladder [vesica urinaria] is a receptacle, whose form, size, and 

 position vary with the amount of its contents. The adult organ in its empty or 

 moderately filled condition hes entirely below the level of the obhque plane of 

 the pelvic inlet; but when considerably distended it rises into the abdomen and 

 shows itself beneath the parietes as a characteristic mesial projection above the 

 symphysis, a projection which in extreme distention of the bladder may extend 

 nearly to the level of the umbilicus. 



79 



