13 60 THE URINOGENITAL ORGANS 



Structure. The ureter is composed of three coats fibrous, muscular, and mucous. 



The fibrous coat (tunica adventitia) is the same throughout the entire length of the duct, being 

 continuous at one end with the fibrous capsule of the kidney at the floor of the sinus, while at the 

 other it is lost in the fibrous structure of the bladder. 



In the pelvis of the ureter the muscular coat (tunica muscularis) consists of two layers, an 

 internal longitudinal and an external circular; the longitudinal fibres become lost upon the 

 sides of the papillae at the extremities of the calices; while the circular fibres become more prom- 

 inent and resemble a small sphincter. In the ureter proper the muscle layers are very distinct, 

 and are three in number an external longitudinal (stratum externum), a middle circular 

 (stratum medium), and an internal longitudinal layer (stratum internum). The external longi- 

 tudinal layer is found more prominent in the lower half or lower third of the ureter. 



The mucous coat (tunica mucosa) is smooth, and presents a few longitudinal folds which be- 

 come effaced by distention. It is continuous with the mucous membrane of the bladder below, 

 while above it is prolonged over the papillae of the kidney. Its epithelium is of a peculiar char- 

 acter, and resembles that found in the bladder. It is known by the name of transitional epi- 

 thelium. It consists of several layers of cells, of which the innermost that is to say, the cells in 

 contact with the urine are quadrilateral in shape, w r ith concave margins on their outer surface, 

 into which fit the rounded ends of the cells of the second layer. These, the intermediate cells, 

 more or less resemble columnar epithelium, and are pear-shaped, with a rounded internal ex- 

 tremity, which fits into the concavity of the cells of the first layer, and a narrow external extremity 

 which is wedged in between the cells of the third layer. The external or third layer consists of 

 conical or oval cells varying in number in different parts, and presenting processes which extend 

 down into the basement membrane. A few racemose glands are at times seen in the mucous 

 coat. 



Vessels and Nerves. The arteries supplying the ureter are branches from the renal, sper- 

 matic, internal iliac, and inferior vesical. 



The nerves are derived from the inferior mesenteric, spermatic, and pelvic plexuses. 



Applied Anatomy. Subcutaneous rupture of the ureter is not a common accident, but occa- 

 sionally occurs from a sharp direct blow on the abdomen, as from the kick of a horse. The ureter 

 may be either torn completely across, or only partially divided, and, as a rule, the peritoneum 

 escapes injury. If torn completely across, the urine collects in the retroperitoneal tissues; if it 

 is not completely divided, the lumen of the tube may become obstructed and hydronephrosis or 

 pyonephrosis results. The ureter may be accidentally wounded in some abdominal operations; 

 if this should happen, the divided ends must be sutured together, or, failing to accomplish this, 

 the upper end must be implanted into the bladder or the intestine. 



Stones (calculi) not uncommonly become impacted in the ureter. This may occur at any 

 part, but most commonly either at the point where the tube is crossing the pelvic brim or at the 

 termination, where it is passing obliquely through the muscular wall of the bladder. In the 

 former case, an incision with its centre opposite and one inch internal to the anterior superior 

 spine of the ilium dividing all the structures down to the peritoneum, enables the operator to 

 reach the ureter by pushing the unopened peritoneum inward; the stone can then be felt in the 

 ureter, the wall of which is incised, 'and the stone extracted, free drainage being provided for the 

 escaping urine. When the stone is impacted at the vesical end of the tube a preliminary incision 

 into the bladder is required, and by scratching through the mucous membrane overlying it the 

 calculus can then be removed. 



The diagnosis of ureteral calculus is sometimes made by an x-ray examination. In identifying 

 any shadows in the picture thus secured, caution must be exercised not to mistake similar shadows 

 thrown by periureteral phleboliths in the pelvic veins as ureteral calculi. 1 



THE URINARY BLADDER (VESICA URINARIA) (Figs. 1110, 1111). 



The urinary bladder is a musculomembranous sac situated in the pelvis, behind 

 the pubes, and in front of the rectum in the male, the cervix uteri and vagina 

 intervening between it and that intestine in the female. The shape, position, 

 and relations of the bladder are greatly influenced by age, sex, and the degree of 

 distention of the organ. During infancy it is conical in shape, and projects 

 above the symphysis pubis into the hypogastric region. In the adult cadaver, 

 when quite empty and collapsed (Figs. 1108 and 1109), it is cup-shaped, and on 

 vertical median section its cavity, with the adjacent portion of the urethra, presents 

 a Y-shaped cleft, the stem of the Y corresponding to the urethra. It is placed 



1 Consult article by George O. Clark in Annals of Surgery, 1909, p. 913. 



