An assessment of the bone age can be made in different manners. Numerical methods calculating the number of existing ossification centers are to inaccurate. The use of "age-of-appearance" tables gives a more accurate evaluation. In both methods, however, x-ray films of several body parts must be made. Therefore, they are complicated and lead to a higher patient radiation exposure. Methods using hand and wrist as a representative area of the whole skeleton are of greater value for routine bone-age assessments. There is a wide-spread use of the Greulich-Pyle atlas. The atlas-method is fully sufficient in the great majority of cases when certain rules are considered. A more detailed information can be achieved by using the so-called "bone-by-bone" evaluation. A score system was introduced by Tanner and Whitehouse which should be used to a greater extent than is done up to now. Metrical methods give no real information about the bone age but additional informations which can be helpful in following examinations with short intervals.