Of all the congenital deformities affecting infants, abnormalities of the fingers and toes are among the most common. Congenital abnormalities of the fingers account for approximately 10% of all deformities. These are due to malformations that occur in early pregnancy, but are often a surprise to parents at birth. Two of the most common deformities include extra digits (polydactyly) and webbed/fused digits (syndactyly).



Extra fingers and toes occur in approximately 2 out of every 1000 births.  The most common site of polydactyly involves an extra fifth toe, but can occur with any digit. Extra digits tend to run in families—in fact, up to 30% of patients have a strong family history of polydactyly.

Polydactyly ranges from a small piece of extra tissue to a full digit involving bones and joints. Your child’s physician will likely order an x-ray to determine if extra bones are present or just extra skin, called “rudimentary” digits.

Rudimentary digits look like skin tags, usually near the thumb or pinky finger on the hands, or next to the fifth toe. If there is no bone involved, the pediatrician or surgeon may be able to tie a small piece of string at the base of the extra finger in the newborn nursery. This cuts off the blood supply to the extra digit, causing the tissue to die and eventually fall off on its own. If there is bone in the extra digit, however, it will have to be amputated around a year of age.



Syndactyly, or webbing between the fingers or toes, is also a common deformity in children and tends to run in families as well. Syndactyly occurs in 1 out of every 2000 births, involving boys more than girls.

The most common fused fingers are the middle and ring fingers. This can involve just the skin, causing a webbed appearance, or in severe cases bones and joints can be fused. In the feet, the webbing usually occurs between the smaller toes. The webbing does not usually cause any problems and there is no treatment needed. Ideally, surgery should be performed before 18 months of age to minimize complications.

Sometimes, syndactyly is also accompanied by polydactyly, or the digits may even be fused together. If this occurs, a hand surgeon will need to assess whether the digits share the same nerves and blood vessels, and if so, must perform corrective surgery when the baby is older.


Other Deformities

There are many other isolated deformities that can occur in fingers and toes. These include:

  • Missing digits
  • Trigger thumb, which occurs when the child is born with an abnormal thumb tendon
  • Misshapen toes, including hammer toes, mallet toes, clawed toes, and inwardly curled toes

Typically, polydactyly and synadctyly are isolated occurrences. However, your child’s pediatrician will likely be on the lookout for other anomalies in your child, including your child’s organs. There are certain genetic syndromes that are highly associated with finger and toe deformities, including Trisomy 13, 18 and 21 (Down Syndrome).

Finger and toe deformities can cause a host of problems to a child. They often have delays in motor skills as well as difficulties in performing daily activities. Also, any type of deformity can lead to teasing and bullying, causing emotional trauma as well.


  • Genetic abnormalities affecting fingers are toes are relatively common birth defects.
  • Abnormalities may include extra digits, missing digits, or fused digits.
  • In many cases, treatment is easy or may not be needed at all.
  • In some cases, surgery may be needed to correct the issue.

Last reviewed by Kristie Rivers, MD, FAAP. Review Date: June 2021


  1. American Academy of Pediatrics. Children with Congenital Hand Anomalies & Malformations.
  2. Nelson Textbook of Pediatrics


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