Urinary Bladder Anatomy and Imaging

The urinary bladder, commonly referred to as the bladder, is a key component of the urinary system. Located in the true pelvis, it functions primarily as a reservoir for urine. Below is a detailed overview of its anatomy, imaging features, and related pathology. (Urinary Bladder anatomy and imaging)


model for urinary bladder anatomy

Gross Anatomy of Urinary Bladder

The bladder has a triangular shape with distinct regions:

  • Posterior base (fundus): Forms the back portion.
  • Superior dome: The top part of the bladder.
  • Anterior apex: Directed behind the pubic symphysis and connected to the umbilicus via the median umbilical ligament (a remnant of the embryological urachus).
  • Inferior neck: Leads to the urethra.

The bladder is lined with trabeculated transitional cell epithelium, except at the trigone, a smooth triangular area on the internal surface of the base. The trigone is defined by:

  • Superolateral angles: Formed by the ureteric orifices.
  • Inferior angle: Formed by the internal urethral orifice.

In males, as the prostate enlarges with age, the trigone may protrude, forming a mild elevation called the uvula of the bladder.


Structural Relationships of Urinary Bladder

  • Urethra: Arises from the neck of the bladder and is surrounded by the internal urethral sphincter. It is separated from the pubic symphysis by the retropubic space of Retzius.
  • Peritoneum: Covers the bladder loosely, except at the ureter insertions and the inferior bladder, where it condenses into pelvic fascia.
    • In males, the peritoneum forms the rectovesical pouch between the rectum and bladder.
    • In females, it forms the vesicouterine pouch and rectouterine pouch (pouch of Douglas).

Arterial Supply of Urinary Bladder

  • Upper part: Supplied by the superior vesical artery (in both males and females).
  • Lower part:
    • Males: Inferior vesical artery.
    • Females: Vaginal artery.
  • Both arteries are branches of the anterior division of the internal iliac artery.

Venous Drainage of Urinary Bladder

  • Males: Drained by the vesical and prostatic venous plexuses, which connect to the internal iliac and internal vertebral veins.
  • Females: Drained by the vesical and uterovaginal plexuses, which connect to the internal iliac veins.

Lymphatic Drainage of Urinary Bladder

  • Upper part: Drains to the external iliac lymph nodes.
  • Lower part: Drains to the internal iliac lymph nodes.

Innervation of Urinary Bladder

  • Autonomic innervation: Provided by the vesical nerve plexus, which includes:
    • Sympathetic fibers: From the hypogastric nerves (originating from the inferior mesenteric ganglion).
    • Parasympathetic fibers: From the pelvic splanchnic nerves (originating from the sacral parasympathetic outflow).
  • Somatic innervation: Provided by the pudendal nerves.

Relations of Urinary Bladder

In Males:

  • Anteriorly: Pubic symphysis.
  • Posteriorly: Rectovesical pouch and rectum.
  • Inferiorly: Obturator internus muscle, levator ani muscle, and prostate.
  • Superiorly: Peritoneum.
  • Laterally: Ischioanal fossa.

In Females:

  • Anteriorly: Pubic symphysis.
  • Posteriorly: Vesicouterine pouch, uterus, cervix, and vagina.
  • Inferiorly: Urogenital diaphragm, pelvic fascia, and perineal membrane.
  • Superiorly: Uterus and peritoneum.
  • Laterally: Ischioanal fossa.

Variant Anatomy

  • Double bladder: Receives ipsilateral ureters and has a separate urethra.
  • Septation: Internal division into two or more compartments.
  • Agenesis: Persistence of the cloaca.
  • Ureterocele: Dilation of the intravesical part of the ureter.

Radiographic Features

The bladder is best evaluated when full.

Plain Radiograph:

  • Appears as a rounded soft tissue mass.

Fluoroscopy (Cystography):

  • The bladder is filled with contrast to assess its structure and function.

Ultrasound:

  • Used to assess bladder wall thickness (normal: 3-5 mm).
  • Ureteric jets can be visualized using color Doppler.

MRI:

  • T1-weighted: Bladder wall and contents appear as homogeneous low signal.
  • T2-weighted: Bladder wall appears as low signal, while urine appears as high signal.

Related Pathology

Structural Abnormalities:

  • Pine cone bladder or Christmas tree bladder.
  • Thimble bladder.

Neoplastic Conditions:

  • Bladder cancer: Includes transitional cell carcinoma and squamous cell carcinoma.

Other Conditions:

  • Bladder diverticulum.
  • Bladder hernia.
  • Ketamine bladder.

Read Further From Authentic Sources:

1. Bladder Anatomy & Function

🔗 National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) – Bladder Basics

2. Imaging Techniques for Bladder Assessment

🔗 Radiopaedia – Urinary Bladder Imaging

3. Cystoscopy & Endoscopic Bladder Evaluation

🔗 Urology Care Foundation – Cystoscopy Procedure

4. Bladder Wall Layers & Histology

🔗 Kenhub – Urinary Bladder Histology

5. Pediatric Bladder Anatomy

🔗 Children’s Hospital of Philadelphia – Pediatric Bladder Conditions

6. Wikipedia

🔗 Wikipedia – Urinary Bladder

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