Urological Anatomy

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Kidneys - Bean Brilliance

  • General: Retroperitoneal. Wt: ~150g. Size: ~11x6x3 cm. Loc: T12-L3 (R lower).
  • Coverings (Inner→Outer): Fibrous capsule, perirenal fat, renal fascia (Gerota's), pararenal fat.
  • Hilum (Ant→Post): 📌 VAU - Vein, Artery, Ureter/Pelvis. Kidney Anatomy: Cross-section with Hilum and Structures, relations)
  • Relations:
    AspectRight KidneyLeft Kidney
    AnteriorLiver, duodenum, hepatic flexure, jejunumStomach, spleen, pancreas tail, splenic flexure, jejunum
    PosteriorDiaphragm, 12th rib, psoas, QL, trans. abdominisDiaphragm, 11th & 12th ribs, psoas, QL, trans. abdominis
  • Arterial Supply: Renal art. (aorta) → segmental → lobar → interlobar → arcuate → interlobular → afferent arteriole.
  • Venous Drainage: Parallels arteries → renal vein → IVC.

    ⭐ Left renal vein longer; receives L. suprarenal & L. gonadal veins.

  • Lymphatics: Para-aortic nodes.
  • Innervation: Renal plexus (symp. T10-L1; parasymp. vagus).

Ureters - Pathway Pipes

  • Retroperitoneal tubes, ~25-30 cm long.
  • Course:
    • Abdominal: Descends on psoas major.
    • Pelvic: Crosses pelvic brim/iliac vessels.
  • Three Constrictions (Sites of calculus impaction):
      1. Pelvi-ureteric junction (PUJ)
      1. Crossing pelvic brim/iliac vessels
      1. Vesico-ureteric junction (VUJ)
  • Blood Supply (Segmental): From renal, gonadal, aorta, common iliac, & internal iliac arteries.
  • Histology: Transitional epithelium (urothelium).
  • Relations: 📌 'Water under the bridge':
    • Females: Ureter passes under uterine artery.
    • Males: Ureter passes under vas deferens.

⭐ The narrowest point of the ureter is the vesico-ureteric junction (VUJ), a common site for calculus impaction.

Male Urogenital Anatomy: Sagittal View

Bladder & Urethra - Reservoir & Release

  • Bladder:
    • Location: Pelvic cavity; retroperitoneal. Apex ant., Base post., Neck inf.
    • Relations: ♂ Ant. to rectum, sup. to prostate. ♀ Ant. to uterus & vagina.
    • Trigone: At base; ureteric orifices & int. urethral meatus.
    • Detrusor muscle: Smooth muscle wall. Normal capacity: 300-500ml.
  • Innervation & Micturition:
  • Urethra:
    • Female Urethra: ~4cm; ext. meatus in vestibule.
    • Male Urethra: ~20cm. 📌 Mnemonic (Parts): 'Prostitutes Make Me Beg Pardon' (Prostatic, Membranous, Bulbar, Penile/Spongy).
      • Prostatic (~3cm): Widest.
      • Membranous (~1-2cm): Narrowest, passes UG diaphragm.
      • Bulbar (~1-2cm): In bulb of penis.
      • Penile/Spongy (~15cm): Longest, in corpus spongiosum.
  • Sphincters: Int. (smooth, involuntary), Ext. (skeletal, voluntary, pudendal n.).

Male and Female Urinary Tract Anatomy

⭐ The membranous urethra is the shortest, least dilatable part, and most prone to injury in pelvic fractures.

Prostate & Testes - Glandular Guards

Prostate:

  • Location: Inferior to bladder, surrounds prostatic urethra; ~20g.
  • Zones & Significance:
    • Peripheral (PZ): 70%; most CaP.
    • Central (CZ): 25%.
    • Transitional (TZ): 5%; BPH.
    • Anterior fibromuscular stroma.
  • Ejaculatory ducts: Pass posterior, open into prostatic urethra.

Prostate gland anatomy and zonal divisions

Testes:

  • Location: Scrotum.
  • Coverings: 📌 'Some Damn Englishman Called It The Testis'; Skin, Dartos, External spermatic fascia, Cremasteric fascia, Internal spermatic fascia, Tunica vaginalis, Tunica albuginea.
  • Blood Supply:
    • Testicular artery: from aorta (L2).
    • Pampiniform plexus: thermoregulation, forms testicular vein.
  • Lymphatics: Para-aortic nodes.
  • Vas deferens: epididymis to ejaculatory duct.

⭐ Most CaP (~70-80%) in peripheral zone, DRE detectable.

High‑Yield Points - ⚡ Biggest Takeaways

  • Kidneys: Retroperitoneal, T12-L3. Segmental arteries are end arteries, infarction risk.
  • Ureteric constrictions: PUJ, pelvic brim, VUJ - common sites for stone impaction.
  • Bladder trigone: Smooth, bounded by ureteric orifices and internal urethral meatus.
  • Testicular drainage: Left vein to left renal vein, right to IVC. Lymphatics to paraaortic nodes.
  • Male urethra: Prostatic (widest), membranous (narrowest, injury prone), spongy.
  • Gerota's fascia encloses kidney/adrenal; Waldeyer's sheath at VUJ helps prevent reflux.

Practice Questions: Urological Anatomy

Test your understanding with these related questions

Stab wounds of the kidneys involve other abdominal organs in a high percentage of cases. Of the organs listed, which one is least likely to be damaged in this patient?

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Flashcards: Urological Anatomy

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Duplex collecting system is strongly associated with vesicoureteral _____ and/or ureteral obstruction

TAP TO REVEAL ANSWER

Duplex collecting system is strongly associated with vesicoureteral _____ and/or ureteral obstruction

reflux

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