A technique to study the passive supports of the uterus.

The present report concerns the position of the portio vaginalis of the uterine cervix when known amounts of downward force are applied to it under anesthesia. It is intended to provide a quantitative assessment of the passive supports of the uterus relatively independent of the active striated muscles in the pelvis. The measurements were made by connecting to the cervix a uterine insufflation cannula with a ruler attached to it and measuring the distance from the hymen to the ectocervix while varying amounts of downward traction were applied to a tenaculum with a spring scale. In 73 asymptomatic patients, the cervix lay above the hymen by the following distance with the amount of traction stated: 0 lb = 3.50 cm, 1 lb = 2.35 cm, 2 lb = 1.65 cm, 3 lb = 1.16 cm, and 4 lb = 0.81 cm. In 22 patients examined independently by two examiners, the mean difference between these measurements was 0.29 cm, and the correlation coefficient for their measurements at each level of traction ranged from 0.86-0.94, depending on the amount of force applied. This technique of measurement could be used to study the influence of such factors as age, race, parity, menopausal status, and obstetric history on the integrity of the passive support system within a population, and can provide a way to obtain objective data to study further the passive supports of the uterus.