The anatomic classification of congenital limb deficiencies is used to classify limb deficiencies.
The anatomic classification is proposed to systematically classify all congenital limb reduction defects and avoid terminology that can be considered imprecise or derogatory 1.
This system is currently (c. 2024) endorsed by the World Health Organization and the Centers for Disease Control and Prevention 2.
Classification
complete absence of limb (amelia)
intercalary defect: absence or severe hypoplasia of a section of a long bone, with normal distal structure
terminal transverse defect: complete absence of all structures distal to a certain point of a limb
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longitudinal defect: absence or hypoplasia of a bone parallel to the axis of a limb
preaxial: affects the medial side of the limb. In the upper limb, it involves the thumb with or without the radius, 2nd and 3rd digits may be involved too. In the lower limb, it involves the hallux with or without the tibia, 2nd and 3rd toes may be involved too
central: affects the central part of all of the 2nd to 4th digits
postaxial: affects the lateral side of the limb. In the upper limb, it involves the 5th digit with or without the ulna, 4th and 3rd digits may be involved too. In the lower limb, it involves the 5th digit with or without the fibula, 4th and 3rd digits may be involved too
pre- and postaxial: mixed preaxial and post axial longitudinal defects