Which polydactyly type is the most common?

Which polydactyly type is the most common?

• A. Central polydactyly
• B. Preaxial polydactyly
• C. Postaxial polydactyly
• D. Mesaxial polydactyly

Answer: (C)

Polydactyly is classified by where the extra digit appears relative to the central axis of the hand or foot. The most common form occurs on the ulnar side of the hand, producing an extra little finger or digits on the side opposite the thumb. This is the postaxial type. Epidemiology across populations shows that postaxial polydactyly is far more frequent than the other forms, which are much rarer. Central (or mesaxial) polydactyly happens infrequently, and preaxial polydactyly (on the thumb side) is less common overall than postaxial. So the postaxial form best matches the typical presentation and is the correct choice.

Polydactyly is classified by where the extra digit appears relative to the central axis of the hand or foot. The most common form occurs on the ulnar side of the hand, producing an extra little finger or digits on the side opposite the thumb. This is the postaxial type. Epidemiology across populations shows that postaxial polydactyly is far more frequent than the other forms, which are much rarer. Central (or mesaxial) polydactyly happens infrequently, and preaxial polydactyly (on the thumb side) is less common overall than postaxial. So the postaxial form best matches the typical presentation and is the correct choice.