It is universally recognized that the true angle of anteversion cannot be determined by any single roentgenographic exposure. Realization of this fact has led to the development
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of three other methods of calculating this angle 1, 2, 4. All of these methods, together with our own, are basically similar. The essential requirement is that some variation of a lateral view be made, and from the projected angle thereon, the true angle is calculated by means of a mathematical formula. One of these methods uses only a single exposure. The other two require an anteroposterior view in addition to the modified lateral view. Comparison of our studies with those previously published would seem to indicate that accuracy is achieved to a similar degree by all four methods. As stated earlier, the chief merit of our method lies in the fact that the calculation is done from roentgenograms already made in order to determine the relationship of the femoral head to the acetabulum. In this way the patient will be spared additional radiation exposure, time will be conserved, and the need for extra equipment will be obviated.