Gross Anatomy of The Kidneys, Ureters and Bladder Flashcards
What are the dimensions and weight of a healthy adult kidney?
Length: 10-11 cm
Breadth: 5-6 cm
Thickness: 2.5-3 cm
Weight: 135-150 g (women slightly lighter than men).
Describe the normal position of the kidneys and common variations.
Normal: Retroperitoneal, extending from T12 to L3 vertebrae; hilum at L1.
Variations:
Horseshoe kidney (fused at lower poles).
Pelvic kidney (ectopic).
Crossed renal ectopia.
Absent kidney (1 in 1200 individuals).
List the key homeostatic functions of the kidneys.
Excretion of metabolic waste and excess water.
Regulation of acid-base balance, electrolytes, and blood pressure (via RAAS).
Hormone production (erythropoietin, active vitamin D).
Filtration, reabsorption, and secretion.
What are the major branches of the renal artery, and why are they surgically important?
Branches: Anterior (superior, anterior superior, anterior inferior, inferior) and posterior segmental arteries.
Importance: Segmental arteries are end arteries (no collateral circulation); damage can lead to ischemia.
Describe the course and constrictions of the ureters.
Course: 25-30 cm long, retroperitoneal; abdominal and pelvic parts.
Constrictions (stone impaction sites):
Pelvi-ureteric junction.
Bifurcation of common iliac artery.
Entry into bladder.
What are the key anatomical features and relations of the urinary bladder?
Features: Trigone (smooth triangular area), rugae (folds), detrusor muscle.
Relations:
Male: Rectum (posterior), prostate (inferior).
Female: Vagina (posterior), uterus (superior).
Compare the male and female urethra.
Male: ~20 cm; 3 parts (prostatic, membranous, penile); narrowest at external meatus.
Female: ~3.8 cm; shorter, opens in vestibule; more prone to UTIs.
Define hydronephrosis and nephrotic syndrome.
Hydronephrosis: Kidney swelling due to urine buildup (e.g., from ureteral obstruction).
Nephrotic Syndrome: Proteinuria, hypoalbuminemia, edema (glomerular damage).
Why is knowledge of renal artery variations critical in surgery?
Accessory renal arteries (common) must be identified to avoid ischemia during nephrectomy or transplant.
What embryological structures give rise to the kidneys?
Pronephros → Mesonephros → Metanephros (definitive kidney).
What are the layers covering the kidney, and what is their clinical significance?
Fibrous capsule (easily stripped in health).
Perirenal fat (cushions kidney).
Renal fascia (Gerota’s anterior, Zuckerkandl posterior; limits abscess spread).
Pararenal fat (external to fascia).
Significance: Protects kidney and guides surgical approaches (e.g., lumbar incision).
Compare the anterior relations of the left vs. right kidney.
Left: Suprarenal gland, spleen, stomach, pancreas, jejunum, descending colon.
Right: Suprarenal gland, liver (hepatorenal pouch), duodenum, right colic flexure.
What structures lie posterior to both kidneys?
Diaphragm, psoas major, quadratus lumborum, transversus abdominis.
Subcostal nerve/vessels, iliohypogastric/ilioinguinal nerves.
Critical note: Costodiaphragmatic recess (risk of pleural injury during surgery).
How is the blood supply to the ureters segmented, and why is this surgically relevant?
Abdominal part: Renal artery, gonadal arteries, aorta.
Pelvic part: Internal iliac branches (vesical, uterine/vaginal in females).
Relevance: Avoid devascularization during surgery (e.g., hysterectomy).
Describe the autonomic innervation of the bladder and its clinical implications.
Sympathetic (L1–L2): Inhibits detrusor, contracts internal sphincter (prevents retrograde ejaculation).
Parasympathetic (S2–S4): Stimulates detrusor, relaxes sphincter (voiding).
Clinical: Damage → urinary retention (e.g., spinal cord injury).
Where are the 3 typical sites of ureteric stone impaction?
Pelvi-ureteric junction.
Crossing iliac vessels (bifurcation of common iliac artery).
Vesicoureteric junction (narrowest in males: external urethral meatus).
What anatomical structures must be preserved during a nephrectomy?
Critical: Contralateral kidney (assess function pre-op).
Vessels: Avoid injury to aorta/IVC, accessory renal arteries (present in ~25%).
Adjacent organs: Colon (left), duodenum/liver (right).
What causes a horseshoe kidney, and how does it relate to the inferior mesenteric artery (IMA)?
Cause: Fusion of lower poles during embryogenesis.
IMA traps the kidney, preventing ascent → lies at L3–L5 (below normal position).
Why is the trigone of the bladder clinically significant?
Smooth muscle (no rugae); sensitive to infection (common UTI site).
Landmark: Ureters enter posterolaterally; urethra exits inferiorly.
Why is the ureter at risk during hysterectomy, and where?
Risk area: Near uterine artery (“water under the bridge”).
Mechanism: Ureter crosses under uterine artery near cervix (may be clamped/cut).
Where do the kidneys and ureters drain lymphatically?
Kidneys: Lateral aortic/caval nodes → cisterna chyli.
Ureters: Follows blood supply (aortic, common/internal iliac nodes).
Why does renal colic cause pain in the groin/genitals?
Afferent nerves (T10–L1) share pathways with genital nerves → referred pain along dermatomes.
What is the lumbar/retroperitoneal approach to the kidney?
Incision: Flank, between 12th rib and iliac crest.
Key steps: Split renal fascia, avoid pleura (posterior) and peritoneum (anterior).
