Part 10

The landmarks of the operation are:--(1) The last rib, of which feel the sloping edge; (2) the crest of the ilium; (3) the outer border of the ‘erector spinæ.’ The incision should be about three inches long, midway between the rib and the ilium. It should begin at the outer border of the ‘erector spinæ,’ and should slope downwards and outwards in the direction of the rib. The edge of the ‘quadratus lumborum,’ which is the guide to the colon, is about one inch external to the edge of the ‘erector spinæ,’ or three full inches from the lumbar spines. The line of the gut is vertical, and runs for a good two inches between the lower border of the kidney and the iliac crest on the left side; rather less on the right.

=Small intestines.=--All the room below the umbilicus is occupied by the small intestines. The coils of the jejunum lie nearer to the umbilicus (one reason of the great fatality of umbilical herniæ). Those of the ilium are lower down.

On the right side, a little below the ninth rib, the colon lies close to the gall bladder, and is, after death, sometimes tinged with bile. Posteriorly, this part of the colon is in contact with the kidney and duodenum.

86. =Bladder.=--When the bladder distends, it gradually rises out of the pelvis into the abdomen, pushes the small intestines out of the way, and forms a swelling above the pubes, reaching in some instances up to the navel. The outline of this swelling is perceptible to the hand as well as to percussion. More than this, fluctuation can be felt through the distended bladder by tapping on it in front with the fingers of one hand, while the forefinger of the other passed up the rectum feels the bottom of the ‘trigone.’

THE PERINEUM.

The body is supposed to be placed in the usual position for lithotomy.

87. =Bony framework.=--We can readily feel the osseous and ligamentous boundaries of the perineum; namely, the rami of the pubes and ischia, the tuberosities of the ischia, the great sacro-ischiatic ligaments, and the apex of the coccyx. This framework forms a lozenge-shaped space. If we draw an imaginary line across it from the front of one tuber ischii to the other, we divide this space into an anterior and a posterior triangle. The anterior is nearly equilateral, and, in a well-formed pelvis, its sides are from three to three and a half inches long. It is called the urethral triangle. The posterior, containing the greater part of the anus and the ischio-rectal fossa on each side, is called the anal triangle.

88. =Raphé.=--A slight central ridge of skin, called the ‘raphé,’ runs from the anus up the perineum, scrotum, and penis. This ‘raphé,’ or middle line of the perineum, is the ‘line of safety’ in making incisions to let out matter or effused urine, or to divide a stricture.

89. =Central point of perineum.=--It is very important to know that a point of the raphé about midway between the scrotum (where it joins the perineum) and the centre of the anus, corresponds with the so-called ‘central tendon’ where the perineal muscles meet. The bulb of the urethra lies above this point, and never, at any age, comes lower down. The artery of the bulb, too, never runs below this level. Therefore the incision in lithotomy should never commence above it. A knife introduced at this point, and pushed backwards with a very slight inclination upwards, would enter the membranous part of the urethra just in front of the prostate gland; pushed still farther it would enter the neck of the bladder. This point, then, is a very good landmark to the urethra in lithotomy, or, indeed, in any operations on the perineum.

The incision in the lateral operation of lithotomy, beginning below the point indicated, should be carried downwards and outwards between the anus and the tuberosity of the ischium, a little nearer to the tuberosity than the anus. The lower end of the incision should reach a point just below the anus.

90. =Triangular ligament.=--In a thin perineum, we can feel the lower border of the deep perineal fascia or the ‘so-called’ triangular ligament of the urethra. The urethra passes through it about one inch below the lower part of the symphysis pubis, and about three-quarters of an inch higher than the central tendon of the perineum. It is important to bear in mind these landmarks in introducing a catheter. If the catheter be depressed too soon, its passage will be resisted by the triangular ligament; if too late, it will be likely to make a false passage by running through the bulb.

91. =Anus.=--One of the most important landmarks which guide a surgeon in his operations about the anus, is a white line at the junction of the skin and mucous membrane. It is easily recognised and is of especial interest, because it marks with great precision the linear interval between the external and internal sphincter muscles. From this line the internal sphincter extends upwards, beneath the mucous membrane, for about an inch, becoming gradually more and more attenuated.

The wrinkled appearance of the anus is caused by the contraction of the external sphincter. At the bottom of these cutaneous folds, especially towards the coccyx, we look for ‘fissure of the anus.’

92. =Landmarks in the rectum.=--Many valuable landmarks may be felt by introducing the finger into the rectum, with a catheter at the same time in the urethra. The principal of these landmarks are the following:--

a. The finger can feel the extent and powerful grasp of the internal sphincter for about one inch up the bowel. (91)

b. =Urethra.=--Through the front wall of the bowel it can most distinctly feel the track of the membranous part of the urethra, exactly in the middle line. This is very important, because you can ascertain with precision whether the catheter has deviated from the proper track.

c. =Prostate gland.=--About an inch and a half or two inches from the anus, the finger comes upon the prostate gland. The gland lies in close contact with the bowel, and can be detected by its shape and hard feel. The finger, moved from side to side, can examine the size of its lateral lobes, their consistence and sensibility.

d. The finger, introduced still farther, can reach beyond the prostate, as far as the apex of the trigone of the bladder. More than this, it can feel the angle between the ‘ductus communes ejaculatorii,’ which forms the apex of the trigone. This is the precise spot where the distended bladder should be punctured through the rectum. The more distended the bladder, the easier can this spot be felt. Fluctuation is at once detected by a gentle tap on the bladder above the pubes (86). The trochar must be thrust in the direction of the axis of the distended bladder; that is, roughly speaking, in a line drawn from the anus through the pelvis to the umbilicus.

e. The fold of peritoneum, called the recto-vesical pouch, is about four inches from the anus, therefore it is not within reach of the finger; and we run no risk of wounding it in tapping the bladder if the trochar be introduced near the angle of the trigone.

f. The finger can feel one of the ridges or folds of mucous membrane which are situated at the lower part of the rectum. This fold projects from the side, and sometimes from the upper part of the rectum, near the prostate. When thickened or ulcerated, this fold occasions great pain in defæcation; and great relief is afforded by its division.

g. Lastly, the finger can examine the condition of the spaces filled with fat on either side of the rectum, called the ischio-rectal fossæ, with a view to ascertain the existence of deep-seated collections of matter, or the internal communications of fistulæ.

=Introduction of catheters.=--In the introduction of catheters the following are good rules. Keep the point of the instrument well applied against the upper surface of the urethra;--depress the handle at the right moment (90);--keep the umbilicus in view;--in cases of difficulty feel the urethra through the rectum, to ascertain whether the instrument be in the right direction. Attention to these rules diminishes the risk of making a false passage, an injury which under great delicacy in manipulation ought never to happen.

=Urethra in the child.=--In children the membranous part of the urethra is, relatively speaking, very long, owing to the smallness of the prostate. It is also more sharply curved, because the bladder in children is more in the abdomen than in the pelvis. It is, moreover, composed of thin and delicate walls. The greatest gentleness, therefore, should be used in passing a catheter; else the instrument is likely to pass through the coats and make a false passage. Hence the advantage of being able to ascertain through the rectum whether the instrument be in the right track and moving freely in the bladder, which can also be easily felt in children.

THE THIGH.

93. =Poupart’s ligament, or crural arch.=--Mark the anterior superior spine of the ilium, the spine of the pubes, and define the line of ‘Poupart’s ligament’ which extends between them. This line is one of our guides in the diagnosis of inguinal and femoral herniæ. If the bulk of the tumour be above the line, the hernia is probably inguinal; if below it, femoral. The line is not a straight one drawn from the spine of the ilium to the spine of the pubes, but slightly curved, with the convexity downwards, owing to its close connection with the fascia lata of the thigh. In many persons it can be distinctly felt; in nearly all its precise course is indicated by a slight furrow in the skin.

For the points about the spine of the pubes, refer to paragraph 69.

94. =Furrow at the bend of the thigh.=--When the thigh is even slightly bent, there appears a second furrow in the skin below that at the crural arch. This second furrow begins at the angle between the scrotum and the thigh, passes outwards, and is gradually lost between the top of the trochanter and the anterior superior spine of the ilium. It runs right across the front of the capsule of the hip-joint. For this reason it is a valuable landmark in amputation at the hip-joint. The point of the knife should be introduced externally where the furrow begins, should run precisely along the line of it, and come out where it ends; so that the capsule of the joint may be opened with the first thrust. In suspected disease of the hip pressure made in this line, just below the spine of the ilium, will tell us if the joint be tender. Effusion into the joint obliterates all trace of the furrow, and makes a fulness when contrasted with the opposite groin.

95. =Saphenous opening.=--In most persons there is a natural depression over the saphenous opening in the fascia lata, where the saphena vein joins the femoral. The position of this opening is just below the inner third of Poupart’s ligament, and about an inch and a half external to the spine of the pubes. This is the place where the swelling of a femoral hernia first appears: therefore it ought to be carefully examined in cases of doubt.