Ureter Anatomy in Pelvic Surgery
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Direct answer
The pelvic ureter enters the pelvis at the brim, crosses the bifurcation of the common iliac artery and runs along the lateral pelvic wall before passing beneath the uterine artery at the lateral fornix of the vagina. The uterine artery crosses above it, the classic water-under-the-bridge landmark. The ureter is most often injured during hysterectomy near the uterine artery, the uterosacral ligament and the ovarian pedicle, so its course must be known before any pelvic clamp or ligature.
What you must remember
- Entry into pelvis: the ureter crosses the pelvic brim at the bifurcation of the common iliac artery, lying in front of the sacroiliac joint.
- Pelvic course: it runs along the lateral pelvic side wall, anterior to the internal iliac artery, and then turns medially toward the bladder.
- Water under the bridge: the uterine artery passes over the ureter at the lateral fornix, about 1.5 to 2 cm lateral to the cervix, which is the landmark for dissection.
- Uterosacral relation: the ureter runs just lateral to the uterosacral ligament near its cervical attachment, a common site of injury during posterior dissection.
- Ovarian pedicle: the ureter runs beneath the ovarian vessels near the pelvic brim, so clamping the infundibulopelvic pedicle can injure it.
- Vesical entry: the ureter enters the bladder obliquely at the ureterovesical junction, which is the reason a short segment has a valve-like action.
- Injury confirmation: intraoperative cystoscopy with a dye or fluorescence agent checks the integrity and the function of each ureter.
A pathway through a difficult hysterectomy
Consider a 46-year-old woman undergoing abdominal hysterectomy for a large fibroid uterus, where the cervix is hard to reach and the field is distorted.
- Find the ureter first. Identify the ureter on the pelvic side wall, using the peritoneum at the pelvic brim, before any clamp is placed on the broad ligament.
- Retract and confirm the artery. Once the ureter is seen, the surgeon retracts it laterally and ligates the uterine artery only after confirming that it lies above the ureter.
- Clamp close to the uterus. The uterine artery should be clamped close to the uterus rather than at its origin, because clamping near the internal iliac risks trapping the ureter in the clamp.
- Look again if the ureter is hidden. If the ureter is not visible, the surgeon takes a careful look at the pelvic side wall, because a fibroid may have displaced it medially or laterally.
- Stent and test when in doubt. Where there is any doubt, a ureteric stent placed before surgery helps the surgeon see the course by palpation, and an intraoperative cystoscopy after the vault is closed confirms that urine is flowing from both orifices.
A suspected injury found early can be repaired with a ureteroneocystostomy or an end-to-end anastomosis. A missed injury presents later with a urinoma or fistula, which is why the check is routinely performed.
Where the exam tries to catch you
Ureter questions test position relative to the vessels and the ovarian pedicle.
- Trap: treating the ureter as an intraperitoneal structure of the broad ligament. Correct: the ureter is retroperitoneal and passes through the parametrium at the base of the broad ligament, beneath the uterine artery, close to the lateral fornix.
- Trap: remembering the uterine artery as passing under the ureter. Correct: the uterine artery crosses over the ureter, not under it, which is the source of the water-under-the-bridge phrase.
- Trap: forgetting the ovarian pedicle. Correct: the ureter lies beneath the ovarian vessels at the brim, so clamping the pedicle during oophorectomy can injure it.
The bladder is the commonest urinary tract injury in gynaecological surgery, but a stem with flank pain, urinoma, a rising creatinine or a delayed urinary leak after surgery points to the ureter.
Frequently asked questions
Which artery crosses the ureter during hysterectomy?
The uterine artery crosses over the ureter at the lateral fornix of the vagina, about 1.5 to 2 cm lateral to the cervix. This relation is the water-under-the-bridge landmark that surgeons use to find the ureter before ligating the vessel.
Where does the pelvic ureter enter the pelvis?
The pelvic ureter enters the pelvis at the pelvic brim, where it crosses the bifurcation of the common iliac artery. It then runs along the lateral pelvic side wall before turning medially toward the bladder.
Why is the ovarian pedicle a site of ureteric injury?
The ureter runs beneath the ovarian vessels near the pelvic brim, so a clamp or ligature placed on the infundibulopelvic pedicle can catch the ureter. Care is needed during oophorectomy or salpingo-oophorectomy for this reason.
How is ureteric injury confirmed during surgery?
Intraoperative cystoscopy after dye injection or fluorescence confirms whether urine flows from each ureteric orifice. An absent efflux from one side suggests injury and requires repair before the operation ends.