I

Failure of formation

Transverse (reduction defect, congenital amputation):

 Description of level (e.g. mid forearm reduction defect)

Longitudinal:

 Radial (radial dysplasia, radial club hand)

 Central (typical cleft hand, lobster claw hand)

 Ulnar (ulna dysplasia, ulna club hand)

Intercalated (phocomelia)

II

Failure of differentiation

Soft tissue:

 Syndactyly

 Trigger digit

 Camptodactyly

 Clasp thumb

Skeletal:

 Clinodactyly

 Tumerous

III

Duplication (polydactyly)

Preaxial (thumb)

Central

Postaxial (little finger)

IV

Undergrowth (hypoplasia)

Brachydactyly

Symbrachydactyly (atypical cleft hand)

V

Overgrowth

Level of involvement of macrodactyly/gigantism

VI

Amniotic band syndrome/constriction ring

VII

Generalized conditions

Achondroplasia, dyschondroplasia, Madelung’s