Parts and fixation apparatus
Anatomically, four parts of the organ are distinguished: the apex (apex vesicae), body (corpus vesicae), fundus (fundus vesicae), and neck (cervix vesicae), which directly continues into the urethra.
Fixation of the organ in the pelvic cavity is provided by several structures:
- The urogenital diaphragm (diaphragma urogenitale) and the anterior bundles of the levator ani muscle (m. levator ani).
- The ligamentous apparatus, including the pubovesical (ligg. pubovesicale) and puboprostatic (ligg. puboprostatica) ligaments.
- The median and medial umbilical folds (plicae umbilicales mediana et mediale).
Additionally, in the subperitoneal region, the organ is covered by a well-defined visceral fascia.
Syntopy of the urinary bladder
The relationship to neighboring structures depends on sex, though there are common features.
- Anterior surface: lies against the pubic symphysis (symphysis pubica) and the superior rami of the pubic bones. The organ is separated from the bony structures by a layer of loose connective tissue forming the prevesical space.
- Superior and lateral surfaces: contact the peritoneum-covered loops of the small intestine, sigmoid colon, and cecum. In women, laterally (closer to the base) it is adjacent to the m. levator ani.
- Posterior surface: in men, it borders the ampulla of the rectum, seminal vesicles, ampullae of the vas deferens, and the terminal parts of the ureters. In women, the uterus lies posteriorly, and in the subperitoneal space, the vagina.
- Inferior surface: in men, it lies against the prostate gland (which surrounds the neck of the bladder) and the beginning of the urethra. In women, the fundus of the bladder rests on the urogenital diaphragm.
Internal structure and trigone of bladder
The wall of the organ consists of a well-developed muscular layer and submucosa, which allows the mucous membrane to form folds.
The exception is the trigone of bladder (trigonum vesicae), located in the region of the fundus. Here, the submucosal layer is entirely absent, the mucosa is tightly fused with the muscles, and therefore the surface remains smooth (no folds).
Boundaries of the trigone:
- Apex: points anteriorly and corresponds to the internal urethral orifice (ostium urethrae internum).
- Base: faces posteriorly and connects the orifices of both ureters.
- Interureteric fold (plica interureterica): runs along the base of the trigone, connecting the ureteric orifices.
The closure apparatus is represented by the involuntary bladder sphincter (m. sphincter vesicae), encircling the beginning of the urethra, and the voluntary urethral sphincter (m. sphincter urethrae), which is located at the level of its membranous part (pars membranacea).
Blood supply, lymph drainage, and innervation
Blood supply derives from the internal iliac artery system (a. iliaca interna):
- Superior vesical arteries (a. vesicalis superior) branch off from the non-obliterated part of the umbilical artery (a. umbilicalis).
- Inferior vesical artery (a. vesicalis inferior) originates directly from the anterior trunk of the a. iliaca interna.
Venous blood collects into plexuses within the wall and on the surface of the organ, draining into the internal iliac vein.
Lymphatic drainage is directed to regional lymph nodes along the external and internal iliac arteries, as well as on the anterior surface of the sacrum. In women, lymphatic vessels form direct connections with the vessels of the uterus and vagina at the base of the broad ligament of the uterus.
Innervation is provided by the superior and inferior hypogastric plexuses, pelvic splanchnic nerves, and the pudendal nerve.
Briefly: answers to topical questions
Which venous plexuses participate in blood drainage from the urinary bladder?
Blood drainage from the urinary bladder involves venous plexuses in its wall and surface, as well as the prostatic venous plexus (in men).
- The veins of the wall and surface drain into the internal iliac vein (v. iliaca interna).
- The prostatic venous plexus (plexus venosus prostaticus) receives veins from the lower part of the urinary bladder and the prostate gland, located posterior to the pubic symphysis and anterior to the prostate.
Which pelvic fasciae cover the urinary bladder?
The urinary bladder is covered by the visceral fascia and prevesical fascia.
- Visceral fascia — pronounced in the subperitoneal region and limits the paravesical cellular space.
- Prevesical fascia (fascia prevesicale) — extends onto the anterior surface of the bladder (serving as its visceral fascia) and sends extensions to the posterior wall.
To easily memorize the boundaries of the trigone of the bladder, imagine an isosceles triangle whose apex points downward toward the internal urethral orifice, while the broad base at the top connects the two ureteric orifices via the interureteric fold.
Class and exam questions
How does the syntopy of the posterior wall of the urinary bladder differ between men and women?
In men, the posterior surface borders the ampulla of the rectum, seminal vesicles, and ampullae of the vas deferens. In women, the uterus is located posteriorly, and inferiorly, in the subperitoneal space, is the vagina.
Why is the mucous membrane smooth in the area of the trigone of the bladder?
In this area, the submucosal layer is entirely absent. The mucous membrane is tightly fused with the muscular wall, preventing the formation of folds.
Which muscles form the sphincter apparatus of the urinary bladder and urethra?
The apparatus consists of the involuntary internal urethral sphincter (m. sphincter vesicae), which surrounds the initial part of the urethra, and the voluntary external urethral sphincter (m. sphincter urethrae), located at the level of its membranous part.
What else to study on this topic
- Topography of the prevesical cellular space
- Syntopy of the pelvic parts of the ureters and vas deferens
- Structure and fasciae of the urogenital diaphragm (diaphragma urogenitale)
- Anatomy of the prostate gland and its relationship to the neck of the urinary bladder
- Venous plexuses of the lesser pelvis and pathways of blood drainage
Master the complete topic in the "Topographic Anatomy" course
This is a summary. The course covers everything tested in classes and exams.
- Complete study guide on "Topography of the urinary bladder" and 2,777 more subject pages
- Assignments and quizzes after every topic — just like in a colloquium
- AI tutor answers questions on the topic anytime
- 91 video lessons on the subject
Other topics in the section "Topographic Anatomy of the Pelvis and Perineum"
Free video lessons: topographic anatomyShort lessons with study notes — no registration required.
Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.