Monarch Disease Ontology id MONDO_0017449 (split hand) is a rare, non-syndromic limb reduction defect, clinically and genetically heterogeneous, characterized by bilateral or unilateral underdevelopment or absence of the central rays of the autopod, with absence of all or just some of the central phalanges and at least part of the associated metacarpal bones, yielding a cleft appearance of the hand. It is frequently associated with syndactyly and aplasia/hypoplasia of remaining digits and metacarpal bones. No other dysmorphic features are observed and development is appropriate for age. Also known as: ectrodactyly of hand, split hand (disease).