ureteral pelvis, or the first main urinal reservoir, collects the urine. from the renal pyramids until full, whence it periodicly contracts, forcing the urine into the ureter toward the second main urinal reservoir, the bladder. The proximal ureteral dilatation or ampulla, the ureteral calices and pelvis, is the first location of calculi formation, and when the calculus irritates it into wild or disordered peristalsis, ureteral colic is the result. Undisturbed ureteral rhythm or the natural periodic ureteral peristalsis which accompanies the normal periodic flow of urine through the ureter, produces no pain.

The distinct ureteral pelvis practicly belongs to erect animals or to the smooth kidney.

The ureteral calices and ureteral pelvis are very variable in size and shape and will hold from two teaspoonfuls to an ounce and a half according to my examination of over one hundred fifty ureters. Perhaps the large-dimensioned ureteral calices and pelvis are hydronephrotic, as the proximal ureteral isthmus, I noticed, was in such subjects generally narrow; perhaps frequent kinking produced occasional hydronephrosis.

The proximal ureteral dilatation or reservoir is the most significant of all ureteral dilatations as the most ureteral surgery has always been accomplished at this point in the removal of calculi, in ureteral drainage and in renal exploration. Fortunately the dorsal surface of the ureteral pelvis is practicly free from blood-vessels and hence can be safely incised extraperitoneally, explored with removal of calculi and sutured or safely drained unsutured. The ventral surface of the ureteral pelvis, or proximal urinal reservoir, is so richly covered with large vessels that exploration would be bloody and dangerous surgery.

In incision of the ureteral calices and pelvis the general rule is that the calices converge into two large arms, a proximal located in the proximal renal pole and a distal arm located in the distal rena! pole. Occasionally smaller calicular tubes lie between them which will become incised.

When the renal cortex is incised to explore the ureteral calices or pelvis the incision should be executed in the exsanguinated renal zone of Hyrtl, that is, one-half inch dorsal to the external lateral longitudinal renal border. This incision will sever the calices obliquely, hence the dorsal and ventral renal segments should be accurately coapted and sutured in position in order to heal perfectly so that the original calicular tubes may convey the urine with the least obstruction due to cicatricial projections or calicular strictures. The proximal urinal reservoir, the ureteral calices and pelvis, is a distinctly rhythmic organ evacuating its contents periodicly when full. It does not depend on attitude or force of gravity.

Pathologic defects of the calices and pelvis lie mainly in defects of their walls (inflammatory products, paresis, tuberculosis or calculus deposited on the wall), producing deficient peristalsis or in the mechanic obstruction to the ureteral stream (calculus, kink, torsion, flexion, stricture). So long as the calicular and pelvic peristalsis is not inter

FIGURE 1.-Five ureters, half life size, three with and two without calices and pelvis. The spindles are obvious, especially those of the woman at 4 and 6. There frequently exists two pelvic spindles, 6 and 6a. VI and VII are ureters from the same subject

Bar M

fered with and especially the ureteral stream is not obstructed the ureteral calices and pelvis perform their function, which is periodic rhythm. However, as soon as any mechanic obstruction to the ureteral stream occurs (as by kink, torsion, calculus, stricture) the nondrainage induces residual deposits in the pelvis, but especially in the less powerfully rhythmic calices with resulting accumulation of bacteria, whence the vicious circle arises in the tractus urinarius exactly similar to the vicious circle arising from obstruction in the pylorus or biliary ductscalculi.

Some years of clinic and operative observations on the tractus urinarius, but particularly the personal autopsic inspection of about six hundred abdomens, have convinced me that the wide range of renal mobility must occasionally kink and compromise the ureter with narrow proximal isthmus or neck, and hence induce ureteral pelvic and calicular dilatation with consequent residual deposits and bacterial accumulation, ending in deposits of calculi in the smaller and quieter calices as well as in ureteral, pelvic and calicular dilatation. Repeated kinking and obstruction of the narrow ureteral neck increasingly cripple the rhythmic power of the calices and pelvis, with an increase of bacteria and calculi in the residual urine of the proximal ureteral dilatation.

The kidney with the calices and pelvis frequently passes one and one-half inches distal from its usual position, hence this not only kinks and flexes the neck or proximal isthmus but it enhances the burden of the periodic rhythm to completely evacuate the urinal reservoir. The calices and pelvis, the proximal ureteral dilatation, periodicly and rhythmicly dilates and contracts every three to five minutes.

The proximal ureteral dilatation, the calices and pelvis, has age relations but scarcely enough functional relation to the tractus genitalis to be of practic importance.

Its age relations are of considerable extent but perhaps chiefly manifest in the calices which in senescence dilate in diameter and elongate in length. The calices lose their shapely form of early adult life. The apex of the renal pyramids atrophy, making more spacious the proximal lumen of the calices. The apertures of the cribrum benedictum (blessed sieve) become larger.

II. THE MIDDLE URETERAL DILATATION OR LUMBAR SPINDLE.

This constitutes a practicly constant fusiform swelling in the lumbar ureter. It is the main proximal ureteral spindle, which may be as much as one-half inch in diameter. The spindle occurs as a heritage of the Wolffian body enhanced from the erect attitude, on account of the flexion or kinking of the ureter and consequent narrowing of its lumen. by the projecting vasa iliaca. The sharp projecting brim of the in their natural course relations. Observe the variation in ureteral calices and pelvis. The major distal arm of the calices is practicly a lateral tributary, while the major proximal arm of the calices is the principal in direction; however, the proximal arm generally has one or two fewer calices. The ureteral dilatations, spindles or reservoirs are: 2, the pelvis; 4, the lumbar spindle; and 6, 6a, the pelvic spindle.

pelvis, and, the distalward movement of the genitals in man account for the middle ureteral isthmus and consequent lumbar spindle. The periodic, rhythmic function of forcing urine through the duct, with localized constrictions in the ureter, accounts for the evolutionary formation of dilatations, spindles. The lumbar spindle is one to three inches in length. The lumbar spindle, though constant, is irregular in location, length, form, number and diameter. It could entertain a large ureteral calculus, and still allow space for the urine to pass laterally to it for some time. Though the urine remains but a short time in the proximal main spindle, yet it is a urinal reservoir, like the ureteral pelvis or bladder, and calculi no doubt may lodge and increase in it.

Rarely minor irregular ureteral dilatations occur in the lumbar segments. The spindle begins on an average about two and one-half inches from the hilus renis. The spindle diminishes gradually proximalward but rapidly and abruptly distalward. It lies on the psoas. muscle. It is more pronounced in woman than in man and is larger on the right than the left side. The lumbar spindle is more distinct in erect animals. It is not very distinct in carnivora (dog, cat) or ruminants (rabbit, cow). It is distinct in the sheep, buffalo, pig, and horse (soliped).

It is chiefly due to the flexura iliaca ureteris whose projection is caused by assuming the erect attitude, which insures a pelvic position of the bladder. The vasa iliaca in the erect animal projects the ureter ventralward causing a kink, flexion or angulation in the ureter which offers obstruction to the ureteral stream and consequently dilates the segment of the ureter proximal to the vasa iliaca. There may be two lumbar spindles, that is, the main one divided. The average diameter of the lumbar spindle is about one-third of an inch. It may be more than one-half inch in caliber. Its average length is about two inches. The diameter of its proximal end (ureteral neck or proximal isthmus) is one-ninth of an inch. The diameter of its distal end (middle isthmus) is one-sixth to one-third of an inch. The right lumbar spindle is shorter and more pronounced than the left, especially in

woman.

I found the diameter of the lumbar spindle varying from onefourth to one-half inch. When the diameter was more than one-half inch it was considered pathologic. If more than one lumbar spindle exists, the diameter is proportionately small. In double ureters the lumbar spindles were exactly similar in location but one was generally smaller. Though the lumbar ureteral spindle varies considerably in location and dimension-diameter, length and form-it is practicly

constant.

The lumbar spindle is located diagonally on the psoas muscle. It is not always regular but may sometimes be composed of two smaller ones succeeding each other, of which the distal one is usually the larger. In rare cases a series of swellings of unequal caliber may succeed one another. The lumbar spindle gradually tapers long and slender proximalward to it-ureteral neck-but bluntly and abruptly at its distal

extremity previous to its passage on the ventral surface of the iliac artery.

The pronounced blunt and abrupt distal ending of the lumbar ureteral spindle is mainly on the right side and is more noticeable in woman. In the evacuated state the lumbar ureter may be observed shimmering through the peritoneum as a flattened pronounced spindle with its blunt end distalward. Though flattened in the cadaver from intraabdominal pressure, while in rhythmic activity it has a cone shape. The large lumbar spindle in the majority of subjects is invaluable in lumbar ureteral surgery. It presents ample wall and caliber for manipulations. It may enable the operator to force a calculus lodged at the middle ureteral isthmus into the largest diameter of the lumbar spindle in order to fragment it by pressure or by the point of a needle introduced at a healthy place in the ureteral wall without ureteral incision. The lumbar spindle allows space for catheterization and for the various methods of ureteral anastomosis.

The strong periodic rhythmic action of the lumbar spindle every three to five minutes and its large urinal stream facilitate the passage of a ureteral calculus, and if the calculus passes the small proximal ureteral isthmus (one-tenth inch) the combined force of the lumbar spindle will likely force it rapidly through the larger middle ureteral isthmus (onesixth inch).

The lumbar spindle is one of the most mobile segments of the ureter and hence can be widely displaced for surgical intervention.

FUNCTIONAL AND AGE RELATIONS.

The lumbar spindle experiences first, functional relations, and second, age relations.

Functional. The lumbar spindle is markedly more pronounced in woman and on the right side.

The arteria ureterica proximal in general is emitted from the ovarian artery as it crosses ventral to the largest diameter of the lumbar spindle, hence the lumbar spindle is liable to be most nourished at its middle point, that is, at its largest diameter. In pubertas (twelve to fifteen years of age) the uteroovarian artery springs into activity and the arteria ureterica proximal becomes distended and engorged with blood, giving extra nourishment to the spindle (to a less degree this occurs in the male). As menstruation arrives the arteria ureterica proximal becomes periodicly engorged, hyperemia exists for about fifteen days during each month, half of the time, and overfeeding the lumbar spindle arises which tends to increase its dimensions, length and diameter. This hypertrophic process is again enhanced by the constant ureteral congestion of pregnancy, further increasing the volume of the spindle. With the cessation of the function of the tractus genitalis the arteria ureterica proximal ceases supplying the spindle with so much periodic blood and the ureteral wall rapidly undergoes a retrogressive process resembling the process in the ductus Botali, the arteria umbilicalis and arteriæ hypogastrice-an arteritis physiologica. It