Handa 9781496386441 Full Sample Chap 1
26
SECTION I Preparing for Surgery
Bladder
Urogenital sphincter muscle
1
Bulbocavernosus muscle
2
3
Schematic
Vagina Levator ani
of circular
Uterus
I
muscle coat
Bartholin gland
Outer longitudinal fibers
Outer longitudinal fibers Urogenital sphincter muscle Inner longitudinal fibers
1
Trigonal sphincter muscle
Urethra
Bladder
Circular fibers
Vagina
Ureter
Urogenital sphincter
2
Rectum
Triangular ligament
Urethra
Vagina
Pelvic fascia
Urogenital sphincter
3
Sphincter
Urethra
Vagina
Urogenital sphincter
x2
FIGURE 1.25 Lateral view of the pelvic organs showing detailed anatomy of the urethra and bladder. Insets demonstrate composition of the smooth muscle fibers of the bladder and bladder neck (top right) and the striated urogenital sphincter complex (left side insets). The compressor urethra is not seen. (The original illustration is in the Max Brödel Archives in the Department of Art as Applied to Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA. Used with permission.)
to the umbilicus by the median umbilical ligament (rem- nant of urachus). The bladder lies against the pubic bones laterally and inferiorly and abuts the obturator internus and levator ani. Posteriorly, it rests against the vagina and cervix. These relations are discussed further in consideration of the pelvic planes and spaces. The blood supply of the bladder comes from the superior vesical artery, which comes off the patent part of the umbilical artery and inferior vesical artery, which is either an independent branch of the internal pudendal artery or arises from the vaginal artery. The nerve supply to the bladder is derived from the vesical plexus, a component of the inferior hypogastric
its structure. It passes through the bladder base in an intramural portion for a little less than a centimeter. This region of the bladder, where the urethral lumen traverses the bladder base, is called the vesical neck. In its distal two thirds, the urethra is fused with the vagina (see FIG. 1.25 ), with which it shares a com- mon embryologic derivation from the urogenital sinus. From the vesical neck to the perineal membrane, which starts at the junction of the middle and distal thirds of the urethra, the urethra has several layers. An outer, circularly oriented skeletal muscle layer (urogeni- tal sphincter) mingles with some circularly oriented smooth muscle fibers. Inside this layer is a longitudinal layer of smooth muscle that surrounds a remarkably vascular submucosa and nonkeratinized squamous epithelium that responds to estrogenic stimulation. The proximal urethral lumen is lined by a urothelial layer.
Copyright © 2019 Wolters Kluwer, Inc. Unauthorized reproduction of the content is prohibited.
plexus. Urethra
The urethral lumen begins at the internal urethral ori- fice (meatus) and has a series of regional differences in
0004290808.INDD 26
4/3/2019 9:30:47 PM
Made with FlippingBook Online newsletter