THE RENAL DUCTS. 1895 



dibula (calyces minores), that proceed from the renal substance, where they surround 

 the papillae. 



The latter are embraced by the expanded bases of the conical calyces, the walls 

 of which are intimately blended with the kidney-substance around the sides of the 

 free part of the papillae, a narrow cleft separating the latter from the enclosing calyx. 

 The epithelium of the papillary ducts is directly continuous with that lining the 

 calyx, while the subepithelial tissue of the latter blends with the intertubular renal 

 stroma. On laying open the calyx, the papilla is seen as a conical elevation project- 

 ing into the funnel-shaped envelope (Fig. 1598); although usually enclosing a single 

 papilla, the calyx may receive two or even more such projections. 



The two general groups of calyces an upper and a lower open into the two 

 large primary subdivisions {superior and inferior pelvis) that join to produce the 

 main compartment of the pelvis. The lower end of the latter emerges through the 

 hilum and arches downward to pass about midway between the hilum and the 

 inferior pole of the kidney insensibly into the ureter; exceptionally this junction 

 is marked by a constriction in the lumen of the canal. Although surrounded in its 

 upper part and smaller divisions by the branches of the renal blood-vessels, the general 

 position of the pelvis within the sinus and as it emerges through the hilum is behind 

 the blood-vessels, the intervals between the renal duct and the other occupants of 

 the sinus being filled with adipose tissue. On the right side the lower part of the 

 pelvis is covered in front by the second part of the duodenum ; on the left by the 

 pancreas. 



The Ureter. This part of the renal duct is a flattened tube which connects the 

 renal pelvis with the bladder. It lies beneath the parietal peritoneum, embedded 

 within the subserous tissue and surrounded by fat, and descends along the posterior 

 abdominal wall to the pelvic brim ; crossing the latter, it follows the lateral wall of 

 the pelvis, curving downward, forward and finally inward along the pelvic floor, 

 to reach the bladder. The general direction of its course is indicated by a vertical 

 line on the surface of the abdomen drawn from the junction of the inner and middle 

 thirds of Poupart's ligament (Tourneux). The average length of the undisturbed 

 ureter is approximately 27 cm. (10.5 in.), the left duct being usually about one 

 centimetre longer than the right in consequence of the higher position of the corre- 

 sponding kidney. Apart from the uncertainty of determining just where the pelvis 

 ends and the ureter begins, its length is influenced by several factors, such as the 

 level of the kidneys and of the bladder, the descent of the renal pelvis, body height, 

 and sex, so that considerable variation is encountered ; the excessive figures some- 

 times given are probably based upon measurements of the ducts after removal and 

 abnormal relaxation. The diameter of the ureter from 4-5 mm. is not uniform, 

 since at certain points, corresponding to changes in the direction or relations of the 

 canal (Solger), constrictions regularly occur, near which the tube exhibits fusiform 

 dilatations or spindles (Schwalbe). The most constant narrowings are situated 

 (i) from 4-9 cm. (1^-3^ in.) below the hilum, at which point the upper isthmus 

 of Schwalbe the diameter of the canal is reduced to almost 3 mm.; (2) near the 

 pelvic brim as the duct crosses the iliac vessels {lower isthmus}, preceded by a fusi- 

 form enlargement {chief spindle} ; and (3) at the lower end of the ureter as the 

 canal penetrates the wall of the bladder. Since its course and relations vary in 

 different parts of its path, the ureter is divided for description into an abdominal and 

 a pelvic portion. 



The abdominal portion (pars abdominalis) from 13-14 cm. (about 5-5% in.) 

 in length begins a short distance below the hilum and descends upon the anterior 

 surface of the psoas magnus muscle and its fascia towards the sacro-iliac articulation, 

 with a slight inclination towards the mid-line (Fig. 1591). The distance between the 

 two ureters at their upper ends is about 9 cm. (3^ in.) and at the pelvic brim about 

 6 cm. (2^ in.). Just before reaching the latter level the ureters obliquely cross 

 the common iliac vessels, approximately the point at which the artery divides into its 

 external and internal divisions, or, especially on the right side, they may pass over 

 the external iliac vessels instead. About midway in their course to the pelvis both 

 ducts are crossed in front, at a very acute angle, by the spermatic (or ovarian) ves- 

 sels and behind and obliquely by the genito-crural nerve. The right ureter passes 



