Of the various abdominal positions, the knee-elbow, as used by Sims as early as 1845, is the most frequently utilized. The patient kneels on the table, the legs resting flat upon it, and the knees being separated about ten inches. The upper portion of the body is supported on the elbows, the forearms lying flat upon the table, or, better still, to either side of the head, which rests on a pillow. The elbows are wide apart, the spinal column assumes a curve, concave upwards. The opening of the pelvis looks nearly directly downwards, the plane of the pelvic inlet meets the horizontal at a very acute angle directed forwards and upwards, approaching the horizontal when the spinal column is greatly depressed, the symphysis is almost vertical, as also the entrance to the vagina and the anus. If the clothing of the patient is well loosened, the muscles of the abdomen relaxed, and if the patient breathes with the thorax, then all the abdominal organs gravitate forwards and downwards, and the pressure in the pelvis becomes negative. • It is sufficient now to pull apart the labia, and air rushes into the vagina, the uterus sinks down wards and the vagina balloons out. The anterior vaginal wall rises and falls synchronously with the respiration, to such an extent often that it is difficult to see into the vagina. (Kristeller's respiratio vaginalis.) The same entrance of air takes place into the rectum when the anus is open, as also into the bladder through an inserted catheter. Where the sphincter vaginas is much relaxed, or that of the anus, the air rushes in spontaneously without separation of the opening into these canals, often audibly, and the same occurs where there is laceration of the perineum. When the patient quickly changes her position, the air is driven out audi bly, unless the precaution is taken to keep the vagina open by the finger, or else by a catheter. The knee-elbow position is of special utility in cases where we wish to examine the pelvic organs in the absence of intra abdominal pressure, or else to test the effect of diminution of this pressure on the position of the uterus in connection with tumors. All the pelvic viscera and tumors gravitate upwards in so far as their attachments will permit, and it is thus often possible to differentiate tumors which appear to be connected with the uterus. Small quantities of fluid, which may have escaped notice in the dorsal position, flow towards the lowest point, and may be recognized by percussion in the neighborhood of the umbili cus; tumors which before occupied the posterior part of the pelvis, ap proach the abdominal wall and the palpating fingers. Palpation is, on the contrary, more difficult, owing to the sagging against the hand of,the abdominal wall and the pelvic contents; every conjoined manipulation is also less readily applicable, as also the simple vaginal touch, since the vagina is stretched out, and the uterus has gravitated forward and down ward, and is less readily reached. When a speculum is inserted, we are able to see the entire vaginal wall and a portion of the posterior pouch, and in this position operations on the anterior vaginal wall are most readily performed.
The knee-elbow position may be assumed on any table or in any bed which is not too soft, and the upper part of the body, since the position is a tiresome one, may be supported on bolsters with the precaution that they do not interfere overmuch with the thoracic breathing. The pelvis
must be so steadied by assistants, as to keep the thighs vertical, for the patients always tend to extend the thighs and to deviate the pelvis an teriorly. To maintain the body in this position during operations, Bozeman has devised a table and fixation apparatus, on which the patient may readily be kept anesthetized.
The pure lateral position, with the knees drawn up, is of advantage for the inspection of the external genital organs, in particular the perineum, the anus and its neighborhood; it may also be utilized for the better pal pation of certain tumors, as for instance in case of floating kidney, and for testing the movability of certain tumors; further, by causing the patient to lie on first one side and then on the other, the alteration of the percussion note in case of fluid in the abdominal cavity may be de termined.
The position devised by Sims and almost uniformly used by him is one between a lateral and an abdominal position. The patient reclines on her left side, so that the genitals are opposite the window, the legs being drawn up about at a right angle to the thorax, the right leg a trifle more than the left; a cushion laid between the knees separates con veniently the legs. The left hand is placed on the back, the thorax against the table, so that the head rests on the left parietal bone. In this position the pelvis is supported on the anterior part of the left crest of the ilium, and on the left trochanter, the right iliac crest being the highest point of the body. The vertebral column is deviated a trifle from the vertical, the sagittal plane of the pelvis intersects the left thigh, the anterior surface of the sacrum looking downward and forward. When the examiner stands behind the patient, about opposite the introitus vaginae, the anterior vaginal wall lies to the right and below, the posterior wall to the left and above, the right lateral wall of the uterus above and to the right, the left wall below and to the left. If the upper part of the body is prone, the anterior part of the body against the table, then the intra-abdominal pressure is lowered, and it becomes the greater the more the thighs are flexed against the thorax, and the nearer the body approaches the pure lateral position. In comparison with the knee-elbow position, the intra-abdominal pressure is greater, but still it may sink to nil.
The right lateral position may be used as well as the left. The harder and more resisting the examining table, the better may the lateral posi tion be assumed. On a soft couch or in bed, the pelvis sinks in so deeply that the great advantage of this position, the lessened abdominal pressure, is largely lost. For the insertion of the duck-bill speculum, the intro duction of the sound, tents and dilators, for the examination of the rec tum, or the combined examination of the rectum and the vagina, for the exposure of the anterior vaginal wall, which in this position also rises and falls with the respiratory movements, the Sims position is very advan tageous, in particular since it is far less unpleasant and tiresome than the knee-elbow.