Symptoms and Causes of Syndactyly

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Syndactyly is a fairly common congenital hand defect, affecting about 1 out of every 2,500 babies. In 50 percent of cases, it affects only one hand. Caucasians are more likely than African-Americans or Asians and to have syndactyly, and boys are more likely to have it than girls.

Different forms levels of syndactyly

The classifications of syndactyly correspond to the condition’s different types and degrees of complexity. Syndactyly can be classified in the following ways:

•  Comparison of Incomplete Syndactyly and Complete Syndactyly.incomplete: the webbing or joining doesn’t extend all the way to
    the fingertips 
•  complete: the webbing or joining extends all the way to the fingertips 
•  simple: the fingers are joined only by soft tissue 
•  complex: the fingers are joined by bone or bony cartilage, as well as
    soft tissue, in a side-by-side fashion 
•  complicated: the fingers are joined by bone or bony cartilage, as well
    as soft tissue, in a fashion other than side-by-side—such as with
    abnormally shaped, extra or missing bones



Causes of syndactyly

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 signs and symptoms

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

When to see a specialist

Your child’s doctor will know by sight that your baby’s fingers are webbed. The doctor will refer you to a hand specialist, who will guide you to a more detailed diagnosis and treatment plan.

Questions to ask your doctor

If your child is diagnosed with syndactyly, you may feel overwhelmed with information. It can be easy to lose track of the questions that occur to you. Lots of parents find it helpful to jot down questions as they arise—that way, when you talk to your child’s doctors, you can be sure that all of your concerns are addressed.

Some of the questions you may want to ask include:

•   What is happening to my child, and why?
•   What will x-rays reveal?
•   What actions might you take after you review my child’s x-rays?
•   Is surgery necessary? What will surgery entail?
•   Will my child be OK after surgery?
•   Will there be restrictions on his activities or capabilities?
•   What will be the long-term effects?
•   What can we do at home?

Syndactyly glossary


   •   The Center for Families at Children’s is dedicated to helping families find the information, services and resources
       they need to understand their child’s medical condition and take part in their care.
   •   congenital: present at birth
   •   embryonic development: development of the fetus in the womb
   •   in utero:in the womb (uterus)
   •   occupational and physical therapy: services offered by trained professionals to help restore function or (re)teach
       basic life skills, like walking or grasping objects  
   •   orthopedics: the medical specialty concerned with diagnosing, treating, rehabilitating and preventing disorders and
       injuries to the spine, skeletal system and associated muscles, joints and ligaments
   •   orthopedic surgeon, orthopedist: a physician specializing in surgical and non-surgical treatment of the spine,
       skeletal system and associated muscles, joins and ligaments
   •   prenatal (fetal) ultrasound: ultrasound performed at several stages of pregnancy; can detect syndactyly in
       the fetus
   •   post-operative (post-op): occurring after surgery
   •   pre-operative (pre-op): occurring before surgery
   •   range of motion (ROM) exercises: physical therapy exercises designed to improve or restore flexion and extension
       of joints
   •   reconstructive surgery: surgery performed to repair and/or restore a body part to normal or as near normal
       as possible
   •   sporadic: occurring without apparent genetic cause
   •   syndactyly: “webbed fingers” or “webbed hand;” one of the most common congenital hand differences
   •   x-rays: a diagnostic test that uses invisible ionizing radiation to produce images of internal tissues, bones, and
       organs onto film
   •   z-plasty: a surgical technique using zig-zag incisions

See our extensive Glossary of Orthopedic Terms.


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