NORMAL RADIOGRAPHIC ANGULATION IN THE 4TH AND 5TH METACARPAL - A REFERENCE GUIDE

Accurate radiographic interpretation of deformities is of value during treatment of disorders of the 4(th) and 5(th) metacarpal. A uniform a nd simple measurement technique and a matching reference standard of t he normal radiographic anatomy is indispensable to do so. Reports repr esenting the normal radiographic angulations of these metacarpals are as yet not available. In 225 plain hand radiographs taken in PA and ob lique directions, the capital- and subcapital angulations, the proxima l articular inclination angle and the shaft bending angle, have been m easured. A simple but effective measurement technique was developed to define their 'normal values'. The reproducibility of this technique w as confirmed in a cadaver study. The obtained values were not dependen t on sex, age, the involved side or the manual dominance. Increased su bcapital inclination in one metacarpal was often accompanied by the sa me trend in the other. The values reveal some variation, but provide a n applicable reference table. They can be used on an individual base f or reliable determination of fracture angulation in the 4(th) and 5(th ) metacarpal in persons over 14 years old with closed growth plates.