The pleura reaches the lower border of the posterior portion of the twelfth rib; it crosses the rib posterior to its middle, if the rib is of normal length, to pass to the eleventh rib. Therefore, to avoid the pleura the incision must not touch the twelfth rib posterior to its middle. One must not forget that the ribs are irregular in number and especially in length. It is necessary to identify the twelfth rib, this may be extremely difficult, and unless the greatest care is used a mistake is liable to occur. If the eleventh rib is mistaken for the twelfth the pleura comes so much farther forward that it is almost certain to be wounded, as has once occurred, producing a fatal result. The ribs may be counted down from the second at the angle of the sternum (Ludwig), remembering the possibility of there being, as we have seen, fourteen ribs on a side, or thirteen, or only eleven. The twelfth rib is frequently so short as to be completely concealed by the muscles; in that case only one floating rib would be seen.

If it is necessary to excise a rib, begin at its anterior extremity, where it is not in contact with the pleura, and scrape off the periosteum from before backward.

Delivering The Kidney

After getting through the abdominal wall one comes down on the fat surrounding the kidney and its capsules. The kidney is to be felt inward and backward toward the spine. Having been located by touch the perirenal fascia and the fatty capsule are to be opened and the kidney pushed and lifted into the wound. Do not go anterior, because there the colon or peritoneum may bulge forward. Once freed from its fatty capsule the normal-sized kidney is sufficiently movable to be lifted clear out of the wound onto the surface. If it is too large the wound must be enlarged downward. Incisions into the kidney substance should be made only when the organ is freely accessible, preferably when out on the surface, and in the manner described on page 426. The frequent existence of an additional artery supplying the lower (or other) portion of the kidney should be borne in mind. If it is desired to open the pelvis it should be sought on the posterior surface, because the veins and arteries are in front of it.

The Suprarenal Glands

The right gland is more on the upper anterior surface of the kidney, while the left is more on the upper inner surface above the hilum. The gland rests on the adipose capsule and is not attached to the kidney, so that when the fatty capsule is stripped off in removal of the kidney the suprarenal gland is left behind. They lie opposite the eleventh and twelfth dorsal vertebrae and are 5 to 6 cm. (2 to 2 1/2 in.) apart. A needle thrust into the eleventh interspace close to the spine would penetrate the suprarenal. The right one lies behind the foramen of Winslow.

Ureter, And Renal Pelvis

The pelvis of the kidney is the upper expanded end of the ureter. It is not simply funnel-shaped, but it branches like a tree. The lower portion joining the ureter is called the common pelvis, and this divides into the superior and inferior pelves; these latter divide into eight or nine calyces which embrace the apices of the pyramids. The deposition of salts in the pelvis causes the formation of renal calculi, which are of the shape of the pelvis in which they occur. The arteries and veins which enter the kidney do so on the anterior surface . of the pelvis; hence the incision for the removal of calculi which is sometimes made in the pelvis itself instead of through the kidney substance, is made posteriorly instead of anteriorly. In making the incision care is to be taken to avoid any unusual veins or arteries which may cross the pelvis, especially at its lower portion.

Fig. 437.   The ureter, showing its course and relations.

Fig. 437. - The ureter, showing its course and relations.

In front of the pelvis of the right kidney is the duodenum, and in front of the left is the pancreas.

The ureters are 25 cm. (10 in.) long when in the body, and 27.5 to 32.5 cm. (11 to 13 in.) long when removed from the body (A. Francis Dixon,

"Cunningham's Anatomy"). The left ureter is a little the longer because the left kidney is the higher. They are flattened tubes with a lumen of 3 mm. (1/8 in.) and possess muscular and fibrous walls. The contraction of the marked muscular walls explains the intensity of renal colic. The back-flow of urine from the bladder in diseased conditions may distend the ureters until they approach in size the small intestine. Course. - The ureter is in two parts, an abdominal, extending to the brim of the pelvis, and a pelvic part, which is about 2.5 cm. (1 in.) longer than the abdominal. The abdominal portion extends from 4 cm. (1 1/2 in.) to the outside of the median line opposite the second lumbar vertebra to 3 cm. (1 1/4 in.) outside of the median line oh a line joining the anterior superior spines of the ilia. It descends on the psoas muscle almost parallel to the median line but inclining a little inward and crosses the brim of the pelvis at the bifurcation of the common iliac artery (the right being sometimes a little lower). It will be observed that at this point the right ureter lies immediately to the inner side of the base of the appendix. There are three narrowed parts; the first or superior isthmus is 7 cm. (2 1/2 in.) below the hilum, where the ureter turns forward on the psoas muscle; the second or inferior isthmus is at the pelvic brim; and the third is where it enters the bladder. Calculi may lodge at any of these points. If this occurs at the brim in the right ureter the case may be mistaken for one of appendicitis, for the location of the two affections would be almost identical. The abdominal ureter does not possess as distinct a sheath as does the pelvic ureter. It is stuck, however, by fibrous tissue to the peritoneum, so that when the latter is raised it comes up with it. The ureters are crossed about their middle and accompanied by the spermatic or ovarian vessels. Just below the middle of the abdominal portion of the ureters the genitocrural nerve emerges from the psoas muscle and passes beneath the ureters from within out. This explains the genital pain in cases of calculi.