Hand, Finger, and Toe Defects
Sometimes a hand or foot does not form completely. Part or all of the hand or foot may be missing. For example, the person may have too few fingers or toes.
In amniotic band syndrome, hand, finger, and toe defects (and other abnormalities) are caused when body parts are constricted by thin strands of tissue from the amniotic sac. The amniotic sac holds the amniotic fluid surrounding the developing fetus in the womb. The strands tangle around the fetus, like strings or rubber bands, trapping parts of its body and restricting growth of the body part.
Polydactyly is extra fingers or toes. The little fingers or toes and thumbs or big toes are the ones most commonly duplicated. The extra finger or toe may be just a nub of fleshy tissue or the extra finger or toe could be fully functioning, having its own nerve endings, bones, and joints.
In syndactyly, fingers or toes do not separate, producing a weblike hand or foot. In simple syndactyly, the soft tissues are fused together. In complex syndactyly, the bones are fused together.
Both polydactyly and syndactyly can occur on their own or as a part of a genetic syndrome such as Apert syndrome.
Surgery can be done to correct a hand, finger, or toe defect and improve function. Some children need a prosthesis, which is an artificial device that replaces a missing body part (see Overview of Limb Prosthetics).