Topography and main parts
When beginning the study of Vesica urinaria, one must first memorize its localization. Anatomy test questions often try to trick students by offering options such as the abdominal cavity, retroperitoneal space, or greater pelvis cavity. Remember once and for all: the organ lies in the lesser pelvis cavity.
Anatomically, the organ is conventionally divided into four distinct parts. Each of them has its own Latin name, which must be known by heart to successfully pass the exam:
- Apex — apex vesicae. This is the anterosuperior narrowed part of the organ.
- Body — corpus vesicae. The largest, middle part, which makes up the main volume.
- Fundus — fundus vesicae. The expanded posteroinferior part of the organ.
- Neck — cervix vesicae. The narrowed lower part that directly transitions into the urethra.
Note that the fundus (fundus) is anatomically directed more posteriorly and inferiorly, which often causes confusion when studying preparations.
Wall structural features
The wall of this hollow organ has a classic layered structure, yet possesses a number of unique features. The layers are arranged from inside out as follows:
- Mucous membrane (tunica mucosa). In most parts, it forms prominent folds when the organ is empty.
- Submucosa (tela submucosa). Ensures the mobility of the mucous membrane and the ability to form folds.
- Muscular coat (tunica muscularis). This is a thick layer that has a special name — detrusor (m. detrusor vesicae). It is the contraction of this muscle that ensures the performance of the organ's main function.
- Outer coat. Depending on the filling degree and the specific section of the wall, it can be represented either by the serous coat (peritoneum) or the adventitial coat (connective tissue).
An important element of the muscular apparatus is the internal urethral sphincter (m. sphincter urethrae internus). This structure is localized directly in the area of the neck (cervix vesicae) and plays a critical role in retaining contents.
Vesical trigone
When studying the internal relief of the organ on macro-preparations, attention is always drawn to a special area located on the fundus of the bladder (fundus vesicae). This area is called the vesical trigone (trigonum vesicae).
Its main distinguishing feature is that in this place the mucous membrane is completely smooth and lacks folds. This is due to the fact that the submucosa is completely absent in the trigone area, and the mucous membrane is tightly fused with the underlying muscle layer.
Blood supply and innervation
Understanding the neurovascular supply of the organ is essential for clinical practice. Arterial blood supply to the organ comes from the iliac vessel system. Specifically — from branches of the internal iliac artery (a. iliaca interna).
Nervous regulation governing the complex work of the muscular layer (detrusor) and sphincter is provided by branches emerging from the specialized vesical plexus (plexus vesicalis).
Briefly: answers to topical questions
Which specific arteries supply blood to the urinary bladder?
The blood supply to the urinary bladder is provided by branches of the internal iliac artery (a. iliaca interna). The main source indicated in the materials is:
- Inferior vesical artery (a. vesicalis inferior) — supplies blood to the bladder fundus and ureters.
Other specific arteries feeding the body and apex of the organ are not detailed in these sources.
What anatomical structures form the apices of the vesical trigone (trigonum vesicae)?
The apices of the vesical trigone (trigonum vesicae) are formed by the internal urethral orifice and the orifices of the two ureters.
- Anterior apex — corresponds to the internal urethral orifice (ostium urethrae internum).
- Posterior apices (base of the trigone) — formed by the orifices of both ureters, which are connected to each other by the interureteric fold (plica interureterica).
The mucous membrane in this area is tightly fused with the muscular coat and lacks folds.
How does the relation of the urinary bladder to the peritoneum change depending on the degree of its filling?
The relation of the urinary bladder to the peritoneum depends on its filling. When full, the urinary bladder occupies a mesoperitoneal position and is covered by the peritoneum on three sides. The sources also indicate that the superior surface of the urinary bladder is covered by the peritoneum.
From which sources is the sympathetic and parasympathetic innervation of the urinary bladder carried out?
Innervation of the urinary bladder is provided by the sympathetic and parasympathetic divisions of the autonomic nervous system.
- Sympathetic innervation — preganglionic neurons lie in spinal cord segments L1–L2. Postganglionic fibers originate from the celiac ganglion, renal, inferior mesenteric, and hypogastric plexuses.
- Parasympathetic innervation — centers are located in sacral segments S2–S4 (or S3–S5). Impulses are conducted via pelvic splanchnic nerves (nn. splanchnici pelvini), switching in the hypogastric (vesical) plexus.
Branches of the vesical plexus (plexus vesicalis) form intramural networks in the organ wall.
Which organs border the urinary bladder (syntopy) in men and women?
The syntopy of the urinary bladder has sex differences.
| Surface | In men | In women |
|---|---|---|
| Anteriorly | Pubic symphysis | Pubic symphysis |
| Posteriorly | Ampulla of the rectum, ampullae of the ductus deferentes, seminal vesicles, and terminal parts of the ureters | Uterus; in the subperitoneal space — vagina |
| Inferior | Initial part of the urethra and prostate gland | Urogenital diaphragm |
| Superior | Loops of the small, sigmoid, and cecum intestines | Intestinal loops adjoin the apex |
| Laterally | — | Levator ani muscle |
The anterior surface is separated from the pubic symphysis by the prevesical space.
To which lymph nodes does lymph drainage from the urinary bladder occur?
Lymphatic vessels of the urinary bladder departing from the muscle layer and fascia head toward:
- sacral lymph nodes;
- external iliac lymph nodes;
- internal iliac lymph nodes.
Lymphatic vessels of the urinary bladder connect with the vessels of the prostate gland, seminal glands, and urethra. Direct connections of the urinary bladder vessels with the vessels of the uterus and vagina at the base of the broad ligament of the uterus are also indicated.
To remember the layers of the wall from inside out, use the mnemonic "Smart Medical Students Sleep Soundly" (Mucosa, Submucosa, Muscular, Serous/adventitial).
Class and exam questions
In which cavity is the urinary bladder located?
The organ is located exclusively within the lesser pelvis cavity.
Where is the trigone of the urinary bladder (trigonum vesicae) located and what is its feature?
It is located at the base of the urinary bladder (fundus vesicae). Its main feature is that the mucous membrane in this area completely lacks folds.
What is the main muscle of the urinary bladder called?
It is called the detrusor muscle, or m. detrusor vesicae, and forms the muscular tunic of the organ.
Where is the internal urethral sphincter located?
The internal sphincter (m. sphincter urethrae internus) is located in the region of the neck of the urinary bladder (cervix vesicae).
What else to study on this topic
- Detailed structure of the muscular tunic (detrusor) and the direction of muscle fibers.
- Topographic relations of the serous membrane (peritoneum) to the urinary bladder during filling and emptying.
- Formation and branches of the vesical plexus (plexus vesicalis).
- Anatomic boundaries and angles of the trigone of the bladder (trigonum vesicae).
Study the complete topic in the Anatomy course
This is a summary. The course covers everything tested in classes and exams.
- Complete study guide on "Urinary bladder" and another 1,363 pages of the subject
- Assignments and quizzes after every topic — just like in a colloquium
- AI tutor answers questions on the topic anytime
- 295 video lessons by subject
Other topics in the section "Splanchnology / Urogenital System"
Free video lessons: AnatomyShort lessons with study notes — no registration required.
Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.