REN. 



235 



The posterior surface of the kidney looks 

 somewhat inwards ; it rests upon the quad- 

 rat us lumbonim muscle, from which it is 

 separated by the anterior division of the tendon 

 of the transversalis ; it is also in contact with 

 the diaphragm, which separates it from the 

 two or three last ribs, and with the psoas 

 muscle, which separates it from the spine. 



From a consideration of these relations, it 

 will be seen that exploration of the kidney, 

 with a view to detect enlargement or tender- 

 ness, may best be made in the lumbar region 

 on either side. It will also be evident that 

 abscess originating in the kidney may extend 

 backwards, and become diffused amongst the 

 muscles in this region, or that it may approach 

 the surface, and discharge itself by an opening 

 in the loins. Cases of this kind are known to 

 occur ; and when renal calculi have been the 

 exciting cause of the suppuration, these have 

 escaped through the same opening in the 

 lumbar region. 



The circumference of the kidney presents, 

 1st, an external border, thick, convex, semi- 

 elliptical, and directed outwards, backwards, 

 and upwards ; 2nd, an internal border, directed 

 inwards, forwards, and downwards, and pre- 

 senting about its middle a deep notch or 

 fissure, the hilum, as it is sometimes called. 

 This notch is more marked posteriorly, where 

 it corresponds to the commencement of the 

 ureter and the pelvis of the kidney, than an- 

 teriorly, where it corresponds to the renal 

 vein. The notch usually contains some adi- 

 pose tissue, which passes in with the blood- 

 vessels, and occupies the space between the 

 substance of the kidney and the pelvis. 



Of the extremities of the kidney, the su- 

 perior, as before stated, is larger than the 

 inferior, and directed somewhat inwards. It 

 is immediately covered by the supra-renal 

 capsule. The liver is above the right, and the 

 spleen above the left. The inferior extremity 

 of the kidney is directed somewhat outwards, 

 and has below it, but at some distance from 

 it, the crest of the ilium. 



The ureter, or excretory duct of the kidney, 

 extends from the hilum of this organ to the 

 base of the bladder. It is a cylindrical canal, 

 with whitish, elastic walls, varying in size from 

 that of a crow-quill to that of a goose-quill. 

 It is usually dilated at its commencement, 

 narrowed in the middle of its course, and again 

 dilated before its entrance into the bladder. 



Its direction is obliquely downwards and 

 inwards to the sides of the base of the sacrum ; 

 it then passes almost horizontally forwards 

 between the layers of peritoneum forming the 

 posterior ligament of the bladder ; lastly it is 

 directed inwards to the side of the base of the 

 bladder, where it takes an oblique course 

 through the wall of that organ, to open on its 

 inner surface by a narrow orifice in one of the 

 posterior angles of the trigone. 



The relations of the ureter are the following : 

 In the notch of the kidney the ureter lies 

 behind the renal vessels. From the pelvis of 

 the kidney to the base of the sacrum it is 

 in contact with the anterior border of the 



psoas muscle ; it is covered by the peritoneum, 

 and is crossed obliquely by the spermatic 

 vessels. The right ureter has the inferior 

 vena cava on its inner side. On a level with 

 the base of the sacrum, each ureter crosses 

 the common iliac, and below this the external 

 iliac artery and vein. In the pelvis the ureter 

 lies in contact with the wall of this cavity, 

 being covered by peritonaeum, and crossing 

 successively the umbilical artery or its ob- 

 literated cord, the obturator vessels, the vas 

 deferens in the male, and the superior and 

 lateral part of the vagina in the female. In 

 that part of its course which is included in the 

 wall of the bladder the ureter is very close 

 upon the neck of the uterus, and is thus liable 

 to become involved in cancerous disease of 

 that organ.* That part of the ureter which 

 lies in contact with the anterior border of the 

 psoas may become affected by disease ex- 

 tending from the substance of the muscle. 

 The pathological museum of King's College 

 contains a preparation in which an abscess, 

 occupying the substance of the psoas muscle, 

 has opened into the ureter. 



The ureter has two distinct coats or mem- 

 branes. 1. An internal mucous membrane, 

 continuous above with the mucous lining of 

 the pelvis of the kidney, and below with that 

 of the bladder. 2. An external fibrous coat, 

 continuous above with the capsule of the 

 kidney and with the pelvis, and below with 

 the muscular coat of the bladder. The minute 

 structure of the coats of the ureter will be 

 described in a subsequent part of this article. 



Blood-ve ssels of the Kidney. The emiifgent -\- 

 or renal arteries are the largest branches of the 

 abdominal aorta, from which they proceed at 

 nearly a right angle. Their origin is about half 

 an inch below the superior mesenteric artery, 

 the right being frequently somewhat lower 

 and longer than the left. Each renal artery 

 passes obliquely downwards, backwards, and 

 outwards towards the hilum of the kidney, 

 giving off in its course branches to the supra- 

 renal capsule, to the ureter, and to the sur- 

 rounding cellular membrane. At the pelvis 

 of the kidney the artery usually lies be- 

 tween the vein and the ureter, the former 

 being in front of, and the latter behind, the 

 artery. In the hilum of the kidney, where the 

 artery is surrounded by reticular and adipose 

 tissue, it breaks up into four or five branches, 

 and these again subdivide into smaller branches, 

 most of which pass in front of the pelvis of 

 the kidney, while a smaller number pass be- 

 hind this part ; their course and distribution 

 in the substance of the kidney will be de- 

 scribed in connexion with the structure of 

 the gland. The right renal artery is covered 

 at first by the vena cava, and then by its 

 corresponding vein ; the duodenum and pan- 

 creas are also in front of it. It crosses the 

 spine and the right psoas muscle. The artery 



* Cruveilhier, Anatomic Descriptive. 



f Insulsa theoria, quo. urinum v;isis secrctam ex 

 pnpillis quasi viiiul<<c>iil(> [irclici civdcbatur, ea sic 

 denominnndi ausain dcdit. Schumlanskv, de Struc- 

 ture Ecnum. 



