Polydactyly and syndactyly are congenital malformations of the fingers and/or toes.
Polydactyly is the presence of extra fingers or toes, and syndactyly is the fusing together or webbing of two or more fingers or toes.
Polydactyly and syndactyly can vary in the degree of severity.
Syndactyly may be either a complete fusion of fingers or toes or a looser webbing of skin between them.
Syndactyly and polydactyly may occur simultaneously when extra digits are fused in a condition known as polysyndactyly.