Classification and Description for External Malformations, with Special Reference to Limb Malformations

Abstract

External malformations includes diverse anomalies. Here, congenital limb malformations are considered as examples of external malformations. There are various classification systems for limb malformations. For hand malformations, Swanson's classification is widely used in Japan. This classification bases on pathogenesis of hand malformations. However, pathogenetic processes are still unknown for many of hand malformations. It may be worth trying to classify limb malfonnations according to hypothetical pathogenetic processes for research purposes. For clinical description, however, a classification system by anatomical features is preferable. The important point is to preserve the details of the actual event for data storage and retrieval. A descriptive system devised for this purpose by Martinez Frias et al. (Teratology, 15: 163, 1977) is worth mentioning here. In this system, all anomalies are classified into three basic types: excess, deficiency, and fusion. The anatomical structure of the affected limb is defined within a two dimensional order: seven segments in the proximo-distal dimension, and eight rays in the preaxial-postaxial dimension. Classification by this system may seem complicated for nonspecialists, but it has advantages; it can be stored and processed in a computer, and be translated into conventional terminology. At present, storage of precise anatomical data is most important to establish a logical and practical classification system for congenital malformations.