Anatomic Study of the Uterosacral Ligaments: Impact on Endometriosis Diagnosis

Background: Uterosacral Ligament (USL) is the most frequent location of deep infiltrating endometriosis.Despite an abundant literature on USL anatomy in genital prolapse, few data are available on normal USL anatomy.This explains the absence of consensus on criteria to diagnose by imaging techniques this specific endometriosis location.Therefore, the aim of the present study was to assess the normal anatomy of USL.Material and methods: Five fresh and five embalmed cadavers of adult female were dissected.The anatomic characteristics of USL at the insertion to the torus uterinum were assessed by measuring the distance between the inner edges of the USLs at the uterine insertion and the distance between the torus uterinum and the upper edge of the posterior vaginal cuff.For the 20 hemipelvis, the length and thickness of the USLs were evaluated every centimeter from the uterus to the sacral insertions.Comparisons of measures between the right and left USL and between fresh and embalmed cadavers were performed.Results: Distance between the inner edges of the USLs at uterine insertion was 1.40.3cm.Distance between the torus uterinum and the upper edge of the vaginal cuff was 1.00.4cm.For the 20 hemipelvis, the mean length of the USL was 70.95cm.USL transverse thickness varied according to the distance from uterine insertion and was steady between 2 and 5cm from uterine insertion with a mean value of 0.50.2cm.The length of the right USL was longer (7.1 vs. 6.8cm)(p<0.01).No difference in the transverse thickness was found between right and left USL.No difference in USLs measures were found between fresh and embalmed cadavers. Conclusion:Our results allow to determine the portion of USL where the measures are reproducible.Moreover, measures of normal USL were evaluated contributing to define cut-off of abnormal USL applicable to imaging techniques in women with suspicion of endometriosis.