Preaxial foot polydactyly (Human Phenotype Ontology id HP_0001841) is duplication of all or part of the first ray. Also known as: Partial/complete duplication of the phalanges of the big toe, Polydactyly affecting the hallux, Preaxial hallucal polydactyly, Preaxial polydactyly of feet, Preaxial polydactyly of foot, Preaxial polydactyly of the feet, Preaxial polydactyly, feet.