1. A method for estimating the location of an anatomical structure in a diagnostic image of a patient, comprising: obtaining the x-ray data in digital format; detecting a first benchmark feature within the x-ray image; detecting a second benchmark feature within the x-ray image; locating an intersection between a first line that extends along the length of the first benchmark feature and a second line that extends through a central point related to the curvature of the second benchmark feature and that intersects with the first line at an angle that is within a predetermined range of angles; and identifying the location of the anatomical structure relative to the intersection.