A system for modeling the pelvic anatomy of a person comprises an apparatus and method for using the apparatus. The apparatus includes a support and a sizing assembly. The support comprises a base and upstanding member. The sizing assembly is movable along the upstanding member to various heights. The sizing assembly includes a pubis stop arm with a pubis stop, and a pelvic seat arm. The pelvic seat arm supports a pair of opposed ischial seats. The pubis arm extends generally horizontally from the upstanding member. The pelvic seat arm has a horizontal ledge for receiving a patient's ischial tuberosity and an adjoining vertical wall for receiving a patient's medial aspect of the ischial ramus. The distance between the pubis stop and pelvic seats is adjustable, the distance between the pelvic seats is adjustable, and the relative angle between the vertical arms of the pelvic seat is adjustable to accommodate for different anatomies.