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Foundations · AnatomyFoundations / Anatomy

Ureter Anatomy

A ~30 cm retroperitoneal S-curve from renal pelvis to bladder with three physiological narrowings (UPJ, iliac crossing, UVJ) where stones impact, and a segmental blood supply you protect by preserving the adventitia.

Orientation

The big picture

The adult ureter is about 30 cm long and follows a smooth S-curve from renal pelvis to bladder, running retroperitoneally along the psoas, crossing the iliac vessels at the pelvic brim, then coursing through the bladder wall. It has an abdominal segment (pelvis → iliac vessels) and a pelvic segment (iliac vessels → bladder).

Golden rule

Three narrowings = UPJ, iliac crossing, UVJ (narrowest); preserve the adventitial sheath to protect a segmental blood supply.

Pathophysiology

Mechanism pathway

Tap any step to see why it happens.

Illustration

Ureter — course & three narrowings

The ureter — course & the three constrictions

The ureter is ~30 cm long and follows a smooth S-curve from the renal pelvis to the bladder. It has three natural narrowings — the classic sites where stones impact: ① the UPJ, ② where it crosses the iliac vessels, and ③ the ureterovesical junction (the narrowest).

BLADDER 1 2 3 Kidney & renal pelvis urine collects, funnels into the ureter ① Ureteropelvic junction (UPJ) pelvis meets ureter — 1st narrowing Abdominal ureter descends on the psoas, smooth S-curve (~30 cm total) ② Crossing the iliac vessels at the pelvic brim — 2nd narrowing Pelvic ureter curves forward into the pelvis toward the bladder ③ Ureterovesical junction (UVJ) enters the bladder wall — 3rd & NARROWEST point
① UPJ — where the renal pelvis tapers into the ureter.
② Iliac crossing — where the ureter crosses the iliac vessels at the pelvic brim.
③ UVJ — where it passes obliquely through the bladder wall; the narrowest point.
The ureter runs ~30 cm from the renal pelvis to the bladder in a smooth S-curve, descending over the psoas, crossing the iliac vessels at the pelvic brim, then curving forward to enter the bladder wall obliquely. Its three natural constrictions — ① the ureteropelvic junction, ② the iliac-vessel crossing, and ③ the ureterovesical junction (the narrowest) — are the classic sites where stones impact. The oblique passage through the bladder wall also forms the anti-reflux flap-valve. Grounded in leading urology references.
Exam

Board traps

Ureter ≈ 30 cm, S-curve, retroperitoneal; three narrowings = UPJ, iliac vessel crossing, UVJ (narrowest) — the stone-impaction sites.

Ureteric blood supply: medial above, lateral in the pelvis — preserve the adventitial sheath.

The uterine artery crosses over the ureter ("water under the bridge") — classic hysterectomy injury site.

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Related topics

Kidney AnatomyBladder AnatomyUreteric Stones
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