Urinary Bladder – Relations

The urinary bladder is a distensible, hollow muscular organ situated in the pelvic cavity. Its anatomical relations vary based on its state of fullness and the biological sex of the individual. In the collapsed state, the bladder lies entirely within the true pelvis, but when distended, it rises into the lower abdomen. The organ maintains key anatomical relationships with the peritoneum, pelvic bones, adjacent pelvic organs, and neurovascular structures. Understanding these relations is essential for surgeries involving the bladder, catheterization, gynecologic procedures, and interpreting cross-sectional imaging.

General Topographic Position

The bladder lies posterior to the pubic symphysis and anterior to the rectum (in males) or vagina and uterus (in females). It is enveloped superiorly and posteriorly by peritoneum, which forms pouches between the bladder and adjacent viscera. Its base (fundus) faces posteriorly, its apex anteriorly, and the neck is the most inferior and fixed portion, continuous with the urethra.

Bladder Surfaces

• Apex: Points anteriorly toward the pubic symphysis
• Superior surface: Covered by peritoneum; varies with filling state
• Inferolateral surfaces: Rest on the pelvic diaphragm and pelvic floor muscles
• Base (fundus): Oriented posteriorly, where ureters enter and the trigone is located
• Neck: Continuous with urethra; most fixed region

Relations in Males

Anterior

• Pubic symphysis (via the retropubic space of Retzius filled with fat and loose connective tissue)
• Puboprostatic ligaments anchor the bladder neck and prostate to the pubis

Posterior

• Rectum: Separated from bladder base by the rectovesical pouch and fascia
• Seminal vesicles: Superior and lateral to the vas deferens and behind the bladder base
• Vas deferens (ductus deferens): Crosses medially to enter the prostate
• Ejaculatory ducts: Travel through prostate just inferior to the bladder base

Superior

• Covered by peritoneum: Forms the floor of the rectovesical pouch
• Small intestine and sigmoid colon may rest on the bladder dome when full

Inferolateral

• Obturator internus muscle
• Levator ani muscle
• Endopelvic fascia between bladder wall and muscular floor

Inferior (Bladder Neck)

• Prostate gland: Directly inferior to the bladder neck; surrounds proximal urethra
• Internal urethral sphincter: Present at the junction of bladder and urethra

Relations in Females

Anterior

• Pubic symphysis and retropubic space (space of Retzius)
• Pubovesical ligaments anchor bladder neck to pubis

Posterior

• Uterus: Separated by the vesicouterine pouch (peritoneal fold)
• Anterior vaginal wall: Directly contacts the bladder base and urethra

Superior

• Body of the uterus: Rests on superior surface of the bladder when anteverted
• Small intestine or sigmoid colon: May contact dome when bladder is distended

Inferolateral

• Obturator internus and levator ani muscles
• Endopelvic fascia and vesical venous plexus

Inferior (Bladder Neck)

• Urogenital diaphragm and pelvic floor: Support bladder base
• External urethral sphincter: Surrounds urethra distal to internal sphincter

Peritoneal Relations

• Males: Covered superiorly by peritoneum forming the rectovesical pouch
• Females: Covered superiorly by peritoneum forming the vesicouterine pouch

As the bladder fills and expands, its superior surface elevates and displaces the peritoneum, potentially pushing it into the anterior abdominal wall — important in suprapubic catheterization.

Vascular and Lymphatic Relations

• Superior vesical arteries: Branches of the umbilical artery; supply the bladder apex and body
• Inferior vesical arteries (males): Branches of the internal iliac; supply base and neck
• Vaginal arteries (females): Often replace inferior vesical artery in females
• Vesical venous plexus: Drains into internal iliac vein
• Lymphatics: Drain into external and internal iliac lymph nodes

Nerve Relations

• Autonomic Plexuses: Inferior hypogastric plexus surrounds the bladder and contributes sympathetic and parasympathetic fibers
• Sympathetic: T11–L2 via hypogastric nerves — controls internal urethral sphincter
• Parasympathetic: S2–S4 pelvic splanchnic nerves — stimulate detrusor contraction
• Somatic: Pudendal nerve (S2–S4) — controls voluntary sphincter

Clinical Correlations Based on Relations

• Retropubic surgical approach: Exploits the space of Retzius between bladder and pubis
• Bladder injury during hysterectomy: Due to its proximity to uterus and anterior vaginal wall
• Suprapubic catheterization: Inserted above the pubic symphysis through anterior bladder wall when distended
• Bladder cancer invasion: May involve rectum (male) or uterus/vagina (female) if tumor breaches posterior wall
• Pelvic radiation: Requires detailed knowledge of bladder-anterior rectal relations to minimize complications