Abstract
A description is given of hysterometry, a method for in vivo determinations of the pressure response to linear increments in volume of the non-pregnant human uterus. The analyses of pressure-volume diagrams obtained during consecutive phases of the menstrual cycle reveal that the volume of the uterine cavity during the secretory phase is larger than during the proliferative phase by a factor of 2 or more. If ovulation does not occur, however, the relation between pressure and volume remains unchanged throughout the interval between two menstrual flows. It is suggested that hysterometry might prove of value for assessing the effect of hormones and pharmacologically active agents upon the myometrium.