At his annual checkup with pediatric hand surgeon Dr. Laurel Benson, 5-year-old Tommy explained that he came in to see her “so you can check my dinosaur fingers”. His parents clarified that when he was younger, he confused “syndactyly” and “pterydactyl” and with pride declared that he was part dinosaur.

What is Syndactyly?

Syndactyly occurs when digits are held together either with just skin or with a combination of skin and bone. This can occur in either the hand or the foot.


Syndactyly is classified as simple or complex and as complete or incomplete.

  • In simple syndactyly, fingers or toes are webbed by soft tissue only.
  • In complex syndactyly, fingers or toes are webbed by bone and soft tissues.
  • In complete syndactyly, the fingers or toes are webbed to the very tip.
  • In incomplete syndactyly, the fingers or toes have a shorter web and the tips are separated.

Is Syndactyly Common?

It is the most common congenital malformation of the limbs and occurs at an incidence of 1 in 2,000 – 3,000 live births.

What Causes Syndactyly?

Early in pregnancy the fingers and toes are normally held in a webbed paddle. At about 16 weeks, the tissue between the fingers and the toes regresses leaving the individual digits free of webbing. In some cases this process is incomplete, leaving some digits webbed together.

What are the Problems Syndactyly Causes?

Of the hand:

  • Glove wear can be an issue both for sports and in cold climates.
  • Grasp of large objects can be compromised.
  • Growth can be altered when fingers of different length are webbed together.
  • Thumb function is limited

Of the foot:

  • Can’t wear flip flops when the first toe (great toe) is webbed.
  • Occasionally, the toenails of the two webbed toes will irritate each other with aggressive sports and running.

How is Syndactyly Diagnosed?

It is usually diagnosed at the time of birth and rarely seen on prenatal ultrasound. Frequently, xrays are used to determine whether complete syndactylies are complex or simple.

How is Syndactyly Treated?

Web space reconstructions involve surgery to separate the syndactylized digits. Nerves, blood vessels, and bones are carefully separated and skin flaps are rotated to resurface the digits. Rarely is there an adequate amount of skin to cover all the surfaces. If necessary, skin graft is removed from another part of the child’s body and transferred to the deficient areas. The best tissue match is from the same extremity. The donor site (area where the graft is taken) is sutured closed with plastic surgery techniques to yield a scar that is cosmetically pleasing. The separated fingers, with their skin grafts, are then protected in either a large bandage or a cast for several weeks while new blood vessels grow into the grafted tissue. Web space surgeries are usually preformed after the child is walking to prevent irritation of the new scar lines unless deformities of adjacent digits seem to be worsening. The earliest releases are usually when a thumb is syndactylized.

What is the Long-Term Outlook for My Child?

Once the skin graft is adequately healed the child can resume all normal childhood activities with the knowledge that the skin graft will grow as the child grows. Occasionally a return to the operating room might be necessary if a web space scar becomes overly tight (web creep).

In the instance of syndactyly involving the second and third toes, reconstruction of the web space between the two toes is not always necessary. Even while webbed together, the function of the foot is unaffected.

Of course, as Tommy matures, he will recognize that indeed he is 100% human. Until then, he continues to enjoy having dinosaur fingers as he performs all of his normal, little boy activities.