The lower abdominal wall and the anterior wall of the bladder may be wanting congenitally. In paralysis of the sphincter at the neck of the bladder distention results. Stones may be found in the bladder.
From the neck of the bladder the urine passes out of the body through the [urethra]. This in the male passes down through the penis and is about ten inches long. Except when urine is passing it is a transverse slit with the upper and under surfaces in contact, while at the end of the penis the slit of the meatus urinarius is vertical. When the penis is flaccid, the urethra describes a sharp curve before its entrance into the bladder, but it becomes approximately straight when the penis is raised at right angles to the body—an important point to remember in catheterization.
In the female the urethra is straight and much shorter, being only about one and a half inches long. The meatus urinarius is in the anterior vaginal wall about one inch behind the clitoris.
Sometimes the urethra is ruptured in a fall. Stricture of the urethra occurs sometimes after gonorrhoea, owing to the formation of scar tissue following ulcer.
CHAPTER XI.
THE PELVIS AND THE
GENITAL ORGANS.
The Pelvis.—Before taking up the pelvic organs, [the pelvis] itself should be described. The name pelvis has been given to the bony ring which is interposed between the spine and the femurs on account of its resemblance to a basin. At the back of this basin or pelvis are the [sacrum] and coccyx, already described in connection with the back, and at the sides and meeting in the median line in front are the two [ossa innominata] or nameless bones, so called on account of their peculiar and indescribable shape. At birth each os innominatum is made up of three bones, the ilium, ischium, and pubes, but about the age of puberty the three become welded into one. At their point of junction is the cavity of the acetabulum for articulation with the head of the femur or thigh bone.
Fig. 62.—Front view of the pelvis, with its ligaments. (Dorland.) a, Anterior sacro-iliac ligament; b, iliofemoral ligament; c, obturator membrane; d, symphysis pubis; e, sacro-sciatic ligament.