CURVE OF THE URETHRA.-In connection with the anatomy of the urethra, it is advisable to give some details of explorations, and of catheterism and the use of instruments in the normal canal.

The lowest point of the urethra is just in front of the triangular ligament, where it lies about one inch beneath the symphysis pubis. From this to the meatus the canal takes any position according to the direction given the penis; toward the neck of the bladder, however, the urethra is said to have a fixed curve. This is not strictly true, for straight instruments may enter the bladder-a proceeding sometimes difficult, often painful, never absolutely indispensable, if indeed necessary. At rest, however, the urethra has a curve which, in the membranous portion, is fixed, and runs on an average at a distance of from two fifths to three quarters of an inch from the symphysis pubis. It varies slightly with individuals and in the same individual at different periods of life, being shorter and sharper in the child, longer in the old man. A distended bladder or enlarged prostate lengthens the

curve.

The proper average curve, as recognized since Sir Charles Bell, and insisted on by Sir Henry Thompson, the one which will mathematically accord with the greatest number of urethra, is that of a circle. three and one-quarter inches in diameter; and the proper length of are of such a circle, to represent the subpubic curve, is that subtended by a chord two and three-quarter inches long.* An instrument made with a short curve of this description will readily find its way through the normal urethra into the bladder without the employment of any force. It is very desirable that instruments intended for habitual use should be so constructed, † inasmuch as many of the difficulties of catheterism are due to a defective curve in the instrument employed. The defect most frequently encountered is a too great straightness of the last half-inch-a deviation of the curve at its most important point. In an instrument properly made (Fig. 12) it will be found that a tangent to the axis of the curve at its extremity will intersect the projected axis of the shaft at a little less than a right angle (n k h). If the curve comprised only a quarter of the circle, the tangent would meet the projected shaft at a right angle (m gh); but instruments made of this length and a little longer, as they are usually found, invariably have the last part of the curve tilted off into a faulty direction, as shown in the plate (Fig. 12), making the angle between a tangent to the axis of the curve at this point and the pro

"In the winter of 1852-'53, assisted by the late Dr. Isaacs, I made a series of careful experiments upon sections of frozen subjects, as well as by injecting the urethra with numerous substances, afterward carefully cutting out the casts. I found the average curve to be identical with the one given above."-VAN BUREN.

An instrument destined for habitual use by the patient is sometimes made half an inch short in the curve, on account of the greater ease of introduction of such an instrument through the pendulous urethra.

jected axis of the shaft obtuse (lj h), and falling within the right angle.

Fig. 13 a and b represent faulty curves-still occasionally encountered on instruments. Fig. 14 shows the correct curve. It is better to prolong the curve around the circle, and even slightly decrease that of the terminal quarter of an inch, as instruments so made are less liable to be defective, and the point is, for all practical purposes, still at right angles to the shaft, and one and three-quarter inch from it. A knowledge of this relative position and direc

jg k FIG. 12.-Instruments as ordinarily made, with faulty curve, Oa. Od (Béniqué). Correctly-curved conical instrument, Ob. Length of natural curve of urethra, f Oh. Length of chord of curve of sound, h 0, 2 inches.

tion of the point is of great importance in difficult catheterism. A moderately short curve is as good as a long one, provided it is accu

rate; indeed better, for, when the instrument is made with the full length of curve, three tenths of the circle, that portion subtended by a

FIG. 14.-Proper curve.

chord of two and three-quarter inches, its point is so far from the shaft that it is sure to "wabble" when the point encounters an obstruction. This objection is all the more applicable to the Béniqué instrument (Fig. 12, dho), on account of its having a posterior as well as an anterior curve.

This "wabbling" is not of serious importance in the healthy canal, but it is very distracting to the surgeon when a tight stricture is to be entered. Here the short conical point, at right angles to the shaft and one and three-quarter inch from it, is vastly superior on account of steadiness, and is equally certain to follow the urethral curve accurately.

EXPLORATION OF THE URETHRA-CATHETERISM.-The introduction of a sound, staff, or catheter into the bladder is generally spoken of as "catheterism." The use of the staff or sound is sometimes denominated "sounding." The manoeuver in either case is the same. There being given a canal of certain dimensions and curvature, and an instrument to fit it, the problem is to introduce the latter into the former. Nothing is easier, although to perform the operation perfectly is less simple than would at first appear. No amount of instruction, no volumes of directions, can teach the student how to pass the sound. He must learn by doing it, first upon the dead, then upon the living body. Some suggestions may, however, be given.

Always make the patient lie down on his back, with his head on a pillow, his legs slightly separated, his body relaxed, his fears quieted, and himself as comfortable as possible. Both hands should be practiced in introducing the sound, and the surgeon should keep his elbow supported during most of the operation, in order that his hand may be more steady. If the right hand is used, the surgeon places himself at the patient's left, and vice

versa. To explore the canal, a simple, blunt, steel instrument, of medium size, is selected, and properly warmed. The penis is gently encircled by the fingers and thumb of one hand, the instrument held lightly with the points of three fingers and the thumb of the other. The shaft of the instrument is held over the fold of the groin, its handle nearly in contact with the skin, from which latter (the integument, first of the groin and then of the abdomen) it is not to be

FIG. 15.

moved away until the point of the instrument is about to enter the fixed portion of the urethra (membranous). The instrument, at first held along the groin, with its point high and handle low (Fig. 15), is entered at the meatus, and the penis is molded up over it. It is not pushed into the urethra, but the urethra is made to swallow the

instrument, as it were. When the curve, and perhaps an inch of the shaft, has disappeared within the meatus, the handle of the instrument is swept around over the surface of the belly, so as to lie exactly over the linea alba, parallel with it, and still close to the integument (Fig. 16). The whole shaft of the instrument is now to be gently pressed toward the feet, being still kept close to and parallel with the surface of the belly (the penis, meanwhile, being lightly grasped behind the corona glandis, and held steady). The

FIG. 16.

point of the instrument should be followed with the little finger of the hand which manages the penis, and, when it gets fairly past the peno-scrotal angle, the whole scrotum, with the testicles and penis, should be largely seized with the hand and pressed up against the pubis, with slight upward traction. The point may now be felt to settle down and adapt itself to the sub-pubic curve, whence on, the weight of the instrument, properly directed, should carry it into the bladder.

As soon as the curve lies well against the symphysis, the scrotum, testicles, and penis should be dropped; the hand which held them takes the instrument, simply steadies it in the median line, and gradually carries the shaft away from the abdomen (Fig. 17), making the handle describe the arc of a circle, and depressing the shaft between the thighs until it lies nearly in the same plane with them. No pushing movement should be imparted to the instrument during this time. The handle is simply made to describe the arc of a circle, and the point in a healthy urethra can not go astray. While the instrument is being depressed between the thighs, the free hand is employed in pressing down upon the mons veneris and root of the penis (Fig. 18), to stretch the suspensory liga

FIG. 17.

ment-a point of importance to the easy introduction of an instrument, and one which supplies to the short curve all the advantages

claimed for the longer Béniqué curve.

When the instrument is in

caught, and without traction made to describe the arc of a circle until it touches the abdomen over the linea alba. It is then carried around to the groin, and, by a tilting motion, unhooked from the urethra, ending exactly where it commenced along the groin, the handle low, the point high.

The first principle of instrumentation in the urethra is to avoid the use of force. Even in a healthy subject, sometimes, the beak of the instrument will become arrested by contraction of the unstriped muscle surrounding the canal. A little patient waiting will overcome this, and the instrument glides on. The arrest of a sound from muscular contraction usually occurs at the entrance of the membranous urethra from spasm of the "cut-off" muscle (spasmodic stricture). The practiced touch rarely fails to detect at the handle of the instrument the slight contractions of the muscular fibers around its point, and in this way diagnosis with organic stricture is easy. Gently holding the instrument in place for a few minutes, with slight forward pressure, will tire out the muscles, and, if the obstruction is muscular, the sound will shortly pass.

At this same point any instrument is liable to be arrested mechanically in a healthy urethra by the triangular ligament. Here, it will be remembered, the urethra is narrower than anywhere else within the orifice, and just in front of this point exists, naturally, the greatest width of urethra. Now, if the canal be flabby, or the instrument not large enough to distend it (a small sound is more liable to catch here than a large one), the point may become arrested along the floor by the triangular ligament, or along the roof (more rarely) in the little fossa lying above the edge of the subpubic ligament. The instrument is known to be arrested by the bulging out of its curve in the perinæ