URETERS SUPRA-RENAL CAPSULES. 727 



unite into arches round the bases of the medullary cones. After receiving the 

 venous plexus from the tubular portion, they accompany the branches of the 

 arteries to the sinus of the kidney, where they finally unite to form a single vein, 

 which terminates in the inferior vena cava. 



The lymphatics of the kidney consist of a superficial and deep set ; they accom- 

 pany the bloodvessels, and terminate in the lumbar glands. 



The nerves are derived from the renal plexus, which is formed by filaments 

 from the solar plexus and lesser splanchnic nerve ; they accompany the branches 

 of the arteries. From the renal plexus, some filaments pass to the spermatic- 

 plexus and ureter. 



THE URETERS. 



The Ureter is the excretory duct of the kidney. It is a cylindrical mem- 

 branous tube, from sixteen to eighteen inches in length, and of the diameter of a 

 goose-quill. It is placed at the back part of the abdomen, behind the peritoneum ; 

 and extends obliquely downwards and inwards, from the lower part of the pelvis 

 of the kidney, enters the cavity of the pelvis, and then passes downwards, for- 

 wards, and inwards, to the base of the bladder, into which it opens by a con- 

 stricted orifice, after passing obliquely, for nearly an inch, between its muscular 

 and mucous coats. 



Relations. In its course from above downwards, it rests upon the Psoas 

 muscle, being covered by the peritoneum, and crossed in front very obliquely by 

 the spermatic vessels ; the right ureter lying close to the outer side of the inferior 

 vena cava. Opposite the sacrum, it crosses the common or the external iliac 

 artery, lying behind the ileum on the right side, and the sigmoid flexure of the 

 colon on the left. In the pelvis, it enters the posterior false ligament of the 

 bladder, and runs below the obliterated hypogastric artery, the vas deferens, in 

 the m^le, passing between it and the bladder. In the female, the ureter passes 

 along the sides of the cervix uteri and upper part of the vagina. At the base of 

 the bladder, it is situated about two inches from its fellow; lying, in the male, 

 about an inch and a half behind the base of the prostate, at the posterior angle of 

 the trigone. 



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

 mucous. 



The fibrous coat is continuous with that surrounding the pelvis. 



The muscular coat consists of two layers of longitudinal fibres, and an inter- 

 mediate transverse layer. 



The mucous coat is smooth, and presents a few longitudinal folds, which 

 become effaced by distension. It is continuous with the mucous membrane of the 

 bladder below ; whilst, above, it is prolonged over the papillae into the tubuli 

 uriniferi. The epithelial cells lining it are spheroidal. 



The arteries supplying the ureter are branches of the renal, spermatic, internal 

 iliac, and inferior vesical. 



The nerves are derived from the inferior mesenteric, spermatic, and hypo- 

 gastric plexuses. 



SUPRA-RENAL CAPSULES. 



The Supra-renal Capsules are usually classified, together with the spleen, 

 thymus, and thyroid, under the head of "ductless glands," as they have no excre- 

 tory duct. They are two small flattened glandular bodies, of a yellowish color, 

 situated at the back part of the abdomen, behind the peritoneum, immediately in 

 front of the upper end of either kidney ; hence their name. The right one is 

 somewhat triangular in shape, bearing a resemblance to a cocked hat ; the left is 

 more semilunar, and usually larger and higher than the right. They vary in size 

 in different individuals, being sometimes so small as to be scarcely detected, at 

 other times large. They measure from #n inch and a quarter to nearly two 



