Landmarks, medical and surgical / by Luther Holden.

  • Luther Holden
Date:
1888
Catalogue details

Licence: Public Domain Mark

Credit: Landmarks, medical and surgical / by Luther Holden. Source: Wellcome Collection.

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    THE PERINEUM 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 lateral lithotomy should always commence below 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 land- mark to the urethra in lithotomy, or, indeed, in any operations on the perineum. The incision in the lateral operation of lithotomy, begin- ning below the central point of the perineum, 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. 106. 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 through the bulb. 107. Anus.—One of the most important landmarks which guide a surgeon in his operations about the anus, is a white line6 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 mem- brane, 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