Organ
Ureteric crossing of the pelvic brim
The ureter's passage over the iliac arterial region
High-yield
The iliac vessels are useful positional landmarks, but this crossing is not a consistently demonstrated major site of stone impaction.
Overview
At the pelvic brim, the ureter changes from its abdominal course to the pelvic sidewall. It passes anterior to iliac vessels near the sacroiliac region, with variation between a common-iliac-division crossing and a more distal external-iliac crossing.
Reference facts
- Location
- Near the pelvic brim and sacroiliac region, anterior to the common iliac division or adjacent external iliac artery.
- Parts
- A continuous transition between the abdominal and pelvic ureter, not a separate anatomical valve.
- Blood supply
- Small branches from nearby iliac vessels join the ureteral adventitial arterial network.
- Innervation
- Autonomic fibers accompany regional aortic and pelvic plexuses; ureteric pain follows lower thoracic and upper lumbar afferents.
- Relations
- Anterior to iliac vessels and close to gonadal vascular structures; in females the ovarian pedicle is an important adjacent relationship.
- Function
- Connects the abdominal and pelvic courses while transmitting peristaltic urine flow; it is not established as a universal physiological obstruction point.
Clinical correlation
A calcification near the expected ureteral course may represent a stone or an unrelated calcified vein. Plain-film position alone does not reliably distinguish them; CT distribution studies have challenged the traditional second-constriction rule.
Frequently asked questions
Where is the ureteric crossing of the pelvic brim located?
The ureteric crossing of the pelvic brim lies near the pelvic brim and sacroiliac region, anterior to the common iliac division or adjacent external iliac artery.
What does the ureteric crossing of the pelvic brim do?
Connects the abdominal and pelvic courses while transmitting peristaltic urine flow; it is not established as a universal physiological obstruction point.
What are the parts of the ureteric crossing of the pelvic brim?
A continuous transition between the abdominal and pelvic ureter, not a separate anatomical valve.
What is the blood supply of the ureteric crossing of the pelvic brim?
The ureteric crossing of the pelvic brim is supplied by the small branches from nearby iliac vessels join the ureteral adventitial arterial network.