Birth Defects Other Polydactyly Syndrome

Polydactyly and syndactyly are congenital defects affecting the fingers and toes. They may be called digital deformities. Polydactyly syndrome is the presence of extra fingers or toes, while syndactyly syndrome refers to the abnormal joining of two or more digits. Treatment for these conditions involves surgery to separate or remove digits.


Syndactyly is the abnormal joining or fusion of digits. It is also sometimes known as webbed toes or webbed fingers. Syndactyly may be classified as follows:

  • Complete syndactyly: This occurs when the digits are joined all the way to the tips.
  • Incomplete syndactyly: This occurs when the fusion affects only part of the digits.
  • Simple syndactyly: In these cases, only skin and soft tissue connect the digits.
  • Complex syndactyly: This is when the bones are joined.

In cases of syndactyly, toes may be less likely to need surgery than fingers. Finger dexterity requires finger separation, while toe fusion is less likely to have detrimental effects on function.

Congenital syndactyly is caused by incomplete fetal development of the hands. The hands begin as paddle-like structures. Individual digits are differentiated later. The feet form in much the same way. When digits do not separate from one another completely, syndactyly can result.


Polydactyly is the presence of additional, or supernumerary, fingers or toes. Several types of polydactyly may present:

  • Radial polydactly: extra or split thumbs
  • Ulnar polydactyly: extra or split small fingers
  • Central polydactyly: extra or split fingers in the middle of the hand.

Radial and ulnar polydactyly are more common than central polydactyly. In polydactyly, toes may also be affected, with additional digits more likely to form by the outside toes than the middle toes.

Like syndactyly, polydactyly occurs with errors in the process of fetal finger differentiation. However, in polydactyly, fingers developing from the paddle-like hand sometimes split too many times rather than too few.

Treatment for Polydactyly and Syndactyly

Some cases of polydactyly and syndactyly may not require treatment. Other cases require surgery. Generally:

  • Polydactyly surgery involves removing supernumerary digits, and closing a skin flap over the area.
  • Syndactyly surgery involves surgically separating the conjoined fingers. Skin grafts are often taken from the abdomen to cover the surfaces of newly separated fingers.

The complexity of the surgical procedures depends on the type of polydactyly or syndactyly. More intricate and invasive procedures are required when bones must be separated (syndactyly) or removed (polydactyly). After surgery on the hands, occupational and physical therapy may be needed to ensure proper use of the hands.


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University of Missouri Children’s Hospital Pediatric Plastic Surgery. (n.d.). Polydactyly. Retrieved April 29, 2010, from:

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