<prompt> Diagonal conjugate is defined as the distance betweenUpper border of symphysis pubis and the sacral promontoryLower border of symphysis pubis and the sacral promontoryLower border of symphysis pubis and the third piece of sacrumLower border of symphysis pubis and tip of sacrum  <response>: The diagonal conjugate is clinically estimated by measuring the distance from the sacral promontory to the lower margin of the symphysis pubis. 