An understanding of growth events is of primary importance in the practice of clinical orthodontics. Maturational status can have considerable influence on diagnosis, treatment goals, treatment planning, and the eventual outcome of orthodontic treatment. Clinical decisions regarding the use of extra oral traction forces, functional appliances, extraction versus non-extraction treatment, or orthognathic surgeries are, at least partially, based on growth considerations. Prediction of both the times and the amount of active growth, especially in the craniofacial complex, would be useful to the orthodontist.