The diagonal conjugate is measured while the woman is in the lithotomy position. Two fingers of the examining hand are placed in the vagina and pressed inward and upward until the middle finger touches the sacral prominence. (The woman may feel the pressure of the examining finger.) The location where the examining hand touches the symphysis pubis is marked by the other hand. After withdrawing the examining hand, the distance between the tip of the middle finger and the marked point is measured with a ruler or a pelvimeter.