Urological Anatomy

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. , relations)
• Relations:

  Aspect	Right Kidney	Left Kidney
  Anterior	Liver, duodenum, hepatic flexure, jejunum	Stomach, spleen, pancreas tail, splenic flexure, jejunum
  Posterior	Diaphragm, 12th rib, psoas, QL, trans. abdominis	Diaphragm, 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)
  • 2. Crossing pelvic brim/iliac vessels
  • 3. 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.

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.).

⭐ 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.

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.