1082 UROGENITAL SYSTEM. , 
elevations separating these areas correspond to the angles along which the different 
muscular planes meet. These ridges can be observed in the hardened kidney after 
its removal from the body, but they are usually not very sharply defined, the 
angles between the muscular planes being very obtuse. 
A kidney hardened in situ (Fig. 7 29) presents an area near the inner part of 
Pleura — 
Pleura 
f Crus of 
Wa \ diaphragin 
12th rib — 
Crus of | 
diaphragm J TL fist lumbar 
External | vertebra 
arcuate = 4 s ~ 
ligament ya —_ HOTT uh TWN Ss 12th rib 
Diaphragm 3 Ih / Ih A\\ \ wT SS Wn ~~ ( External 
Spleer gis HU) | fae} ee re iit, * - jarenate 
tie: Wi} ‘ \ Aine . (ligament 
eee Diaphragm 
Kidney 
Quadratus Liver 
lumborum 
Small _ 
intestine 
Fat beneath 
colon 
| 
| Quadratus 
lumborum 
lliae crest 
— Tliae crest 
Fic. 728.—THE PosrerRton RELATIONSHIPS OF THE KipNkEYs. ‘Tbe dotted lines indicate the contours of the 
kidneys. The drawing is made from a model prepared by Professor Cunningham. 
its posterior surface adapted to the anterior aspect of the psoas muscle. This 
part of the posterior surface looks inwards and slightly backwards. Farther out 
there is a larger area which, resting against the quadratus lumborum, looks more 
directly backwards. These two areas are separated by a rounded ridge which fits 
into the angle between the muscles mentioned. Beyond the area in contact with 
the quadratus lumborum is the thick outer border of the kidney. 
Towards the upper end of the kidney the posterior surface slopes forwards and 
rests upon the diaphragm. Indeed the upper part of the kidney is, as a whole, 
bent slightly forwards, following that part of the arch of the diaphragm on which it 
rests, and thus a narrow interval is left, in which the pleural cavity passes down behind 
the upper end of the kidney (Fig. 7 28). This relationship of the pleural cavity to 
the kidney is of importance in connexion with surgical operations performed in 
the lumbar region. The portions of the diaphragm to which the kidney is apphed 
are the crus and the parts arising from the last rib and arcuate ligaments. 
In addition to these surfaces or facets for the muscles with which it is in contact, the posterior 
aspect or outer border of the kidney often shows a groove for the last rib, another for the external 
arcuate ligament, and two or three depressions for the tips of the transverse processes of the upper 
two or three lumbar vertebre. In some cases also faint narrow grooves are to be seen for the 
nerves which pass downwards and outwards between the kidney and quadratus lamborum— 
namely, the last dorsal nerve and the ilio-hypogastrie and ilio-inguinal nerves. 
