Descriptive system for congenital limb anomalies.

A descriptive system for the nomenclature, notation and classification of congenital limb malformations, suitable for clinical, epidemiological and experimental use is presented. Every developmental limb anomaly is described by stating the type of anomaly and the affected anatomic structure. All anomalies are classified into three basic types: excess, deficiency and fusion. The anatomic structure of the affected limb is defined within a two dimensional order. This system was used to describe 652 cases with isolated developmental limb anomalies obtained from two series of observations. The observed data are presented in a progressively expanded classification ranging from 4 to 497 diagnostic categories. Observed incidence rates for the four main types of anomaly from a sample of 297,299 consecutive livebirths, are: excess: 1.22; deficiency: 0.17; fusion: 0.20; combined: 0.24 per thousand.