THE KIDNEYS. 1081 
relationship of the kidneys to the lower two ribs is very inconstant, owing 5 partly 
to the great variability in‘size and inclination of these bones (Fi 1g. 728). . 
The lower ends of the kidneys are situated from 14 to 2 inches above the 
highest part of the crest of the ilium. This distance is, of course, usually greatest 
on the left side. 
The kidneys are placed behind the peritoneum, and project into the posterior 
part of the abdominal « cavity. Each is surrounded by a considerable amount of 
Fic. 727.—OUTLINE OF A TRANSVERSE SECTION THROUGH THE BODY AT THE LEVEL OF THE First LUMBAR 
VERTEBRA. The kidneys are seen one on each side of the vertebral column (E). The letter B is 
placed upon the right kidney, and its intimate relationship to the liver (A) is well seen. The left kidney 
at this level is closely related to the spleen (D. J. Cunningham). 
loose tissue, often loaded with fat, the fatty tissue (capsula adiposa) being present 
in greater quantity round the margins, and only to a small extent in front of and 
behind the kidney. In the fat the renal vessels and nerves lie before they enter 
the organ, and the adipose tissue 1s continued, along with the vessels, through the 
hilus into the kidney sinus, where it fills up all the space unoccupied by the vessels 
and nerves. 
The kidney is not held in its place by any hgaments or special folds of peri- 
toneum, but its fixation depends, to a large extent, on the pressure and counter- 
pressure which is exerted upon it by neighbouring structures. 
The long axis of each kidney is somewhat oblique, as the upper end of the organ 
approaches nearer to the middle line than the lower end. The surface of the 
kidney, which is apphed against the muscles forming the posterior wall of the 
abdomen, looks, as a whole, backwards and inwards, and that which projects into 
the abdominal cavity looks forwards and outwards. Hence it happens that the 
outer border of the kidney lies on a posterior plane to the inner border. The 
kidney is rotated in this manner on its long axis to such a degree that the inner 
margin and hilus are scarcely visible from behind, and but a limited view of the 
outer border can be obtained in front (Figs. 729 and 730). 
Posterior Relations and the Posterior Bariice of the Kidney.—The muscles 
of the posterior abdominal wall on which the kidney rests are the psoas, the 
quadratus lumborum, the diaphragm, and the transversalis abdominis. The 
abdominal surfaces of these muscles do not le on the same plane, but slope 
towards one another, and thus the bed on which the kidney rests is not flat. The 
posterior aspect of the kidney, when in situ, adapts itself to the inequalities of the 
surface against which it is placed, and so we find on a kidney which has been care- 
fully fixed and hardened before it has been disturbed, areas marked off for the 
different planes of these muscles. When the kidney is in position, ridges or 
