Any diameter of the pelvis found by measuring a straight line between any two points. Anteroposterior: the distance between the sacrovertebral angle and the symphysis pubis. Bi-ischial: the distance between the ischial spines. Conjugata diagonalis: the distance between the sacrovertebral angle and the symphysis pubis. Conjugatavera: the true conjugate between the sacrovertebral angle and the middle of the posterior aspect of the symphysis pubis (about 1.5 cm less than the diagonal conjugate). Intercristal: the distance between the crests of the ilia. Interspinous: the distance between the spines of the ilium. Intertrochanteric: the distance between the greater trochanters when the hips are extended and the legs are held together. Obstetrical conjugate: the distance between the promontory of the sacrum and the upper edge of the symphysis pubis.