Body of Urinary Bladder: Anatomy, Location, Relations, Function, Clinical Significance, MRI & CT Imaging

Topic

Body of urinary bladder

The body of the urinary bladder is the main central portion of the bladder, lying between the apex and the fundus. It serves as the largest expandable part of the bladder, accommodating urine as it fills. The bladder is a hollow muscular organ located in the anterior pelvis, posterior to the pubic symphysis and anterior to the uterus in females or rectum in males. The body plays a central role in urinary storage and contributes to the distensibility of the bladder wall.

Synonyms

Corpus vesicae
Bladder body
Central portion of the urinary bladder

Location and Boundaries

Superiorly: Dome (apex) of the bladder and peritoneum
Inferiorly: Base (fundus) and bladder neck
Anteriorly: Posterior surface of the pubic symphysis, retropubic fat space (space of Retzius)
Posteriorly: Uterus and cervix in females; seminal vesicles, vas deferens, and rectum in males
Laterally: Pelvic fascia, obturator internus muscle, and pelvic sidewall

Relations

In females: Lies anterior to uterus and superior vagina
In males: Lies anterior to rectum, with seminal vesicles and vas deferens posteriorly
Superior surface is covered by peritoneum, forming part of pelvic reflections
Surrounded by perivesical fat and connective tissue

Function

Acts as the reservoir for urine storage
Provides distensible muscular wall that can expand significantly without marked rise in intravesical pressure
Contracts during micturition to expel urine through the bladder neck and urethra
Plays an important role in urinary continence and voiding reflexes

Clinical Significance

Infections (cystitis): Affect bladder wall and mucosa
Tumors: Transitional cell carcinoma often arises in bladder body or trigone
Trauma: Bladder rupture (intraperitoneal or extraperitoneal) may involve bladder body
Pelvic surgery: Body of bladder is displaced in gynecological and urological procedures
Imaging importance: Bladder distension is essential in pelvic MRI for proper organ visualization

MRI Appearance

T1-weighted images:

No urine: Bladder lumen is collapsed, appearing dark; perivesical fat is bright
With urine: Urine appears dark (low signal); bladder wall appears thin and dark
Fat: Bright surrounding the bladder, delineating the margins

T2-weighted images:

No urine: Bladder lumen not well visualized, wall appears as low signal band
With urine: Urine appears bright; bladder wall appears thin and dark
Fat: Intermediate to bright, surrounding bladder externally

STIR (Short Tau Inversion Recovery):

No urine: Pouch appears collapsed, with surrounding suppressed fat
With urine: Urine appears bright hyperintense
Fat: Suppressed (dark), helping to outline the bladder margins

T1 Fat-Sat Post-Contrast:

Normal bladder wall: Shows thin, uniform enhancement
No urine: Collapsed lumen; perivesical fat suppressed (dark)
With urine: Lumen remains dark; tumors, inflammation, or infection show focal or diffuse enhancement of wall
Pathology: Tumors show irregular thickening and nodular enhancement; cystitis shows diffuse wall enhancement

CT Appearance

Non-Contrast CT:

No urine: Collapsed bladder, wall seen as thin soft tissue band
With urine: Urine appears low attenuation (~0–20 HU); bladder wall appears as thin soft tissue density
Fat: Seen as low-density tissue surrounding the bladder (perivesical fat)

Post-Contrast CT:

Normal bladder wall: Enhances thinly and uniformly
With urine: Contrast-opacified urine appears bright, delineating wall
Pathology:
- Tumors: Focal enhancing masses or irregular wall thickening
- Cystitis: Diffuse wall thickening with homogeneous enhancement
- Trauma: Contrast extravasation if rupture present

MRI image

CT image

Topics