Skeletal Maturation in the Early Human Fetus

Abstract

In the study of problems of disordered growth, the concept of skeletal maturity as an index of biological development separate from chronological age has been of great value. The original “atlas” concept applied to an anatomical area of the skeleton, introduced by Todd and refined by Greulich and Pyle has been greatly extended by the “bone-specific” approach suggested first by Acheson (1954, 1957). The simple ordinal method of scoring bone stages gave no weight to the relative value of different centres of ossification. The concept of using weighted scores rather than simple ordinal ranking was perfected by Tanner and coworkers, especially in their TW2 system (1975). In this the numerical scores were weighted so as not to give undue weight to any particular bone or series of bones (e.g. digital ray) in the assessment, but the problem of assigning weightings to each individual stage of each bone is a mathematically monumental task, although it would be biologically preferable A stage which is attained and passed in a short period of time is of more “value” than one which exists for a lengthy period.