Definition of Webbing of the fingers or toes:

Webbing of the fingers and toes is called syndactyly. It refers to the connection of two or more fingers or toes. Webbing usually only involves a skin connection between the two areas, but in rare cases may involve the connection (fusion) of bones. 

Considerations:

Syndactyly may be discovered during an examination of an infant or child. In its most common form, it is seen as webbing between the second and third toes. This form is often inherited and is not unusual. Syndactyly can also occur along with other birth defects involving the skull, face, and bones.

The web connections usually run up to the first joint of the finger or toe, but may run the entire length.

"Polysyndactyly" describes both webbing and the presence of an extra number of fingers or toes.

Common Causes:

Relatively common causes:

• Down syndrome
• Hereditary syndactyly

Extremely rare causes:

• Apert syndrome
• Carpenter syndrome
• Cornelia de Lange syndrome
• Pfeiffer syndrome
• Smith-Lemli-Opitz syndrome
• Using the medication hydantoin during pregnancy (fetal hydantoin effect)