Syndactyly | Symptoms & Causes | Diagnosis

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What is Syndactyly?

A condition in which fingers or toes are joined together. Syndactyly can involve the bones (bony syndactyly) or just the skin (cutaneous syndactyly, or webbing).


During normal embryonic development (while the baby is still in the womb), the hand initially forms in the shape of a paddle; then — at about the sixth or seventh week of gestation — splits into separate fingers. Syndactyly results if there’s an irregularity in this process: The fingers fail to divide normally (failure of differentiation) and the result is a webbed hand.

Some cases of syndactyly occur in isolation and sporadically — meaning by themselves, for no identifiable genetic reason. In about 10 to 40 percent of cases, the condition occurs as an inherited trait. And in some cases, syndactyly is an accompanying defect in a genetic syndrome, such as Poland syndrome, Apert syndromeor Holt-Oram syndrome.

Syndactyly is visible at birth. It may also be visible in utero by fetal ultrasound.

Diagnosis & Tests

Syndactyly may be seen by ultrasound prenatally, and is apparent at birth. Your doctor will use x-rays to assess the underlying structure of your baby’s fingers and determine a course of treatment. If the syndactyly is associated with a genetic syndrome, doctors will evaluate the baby’s entire upper extremity, chest feet and head/face to detect other abnormalities.

Prevention & Risk Factors

Treatments & Therapies

Orthopedic surgeons and plastic surgeons usually treat children with syndactyly by surgically releasing the fingers from their webbing. This procedure is typically performed when the child is between 1 and 2 years old. At this age, the child is old enough to tolerate anesthesia and surgery but is not at risk for missing developmental milestones such as grasping (prehension).

In general, the skin is split evenly between the two fingers with zig-zag incisions (z-plasty). Only one side of a finger is separated at a time in order to avoid complications related to the skin coverage and blood supply of the affected finger. For this reason, if your child has multiple fingers that are joined, more than one surgical procedure will be needed.