Congenital deformities of the hand are common (occurring in 2.3 per 1,000 births) but most of these conditions are relatively minor, not affecting function.
Various inherited genetic anomalies have been classified:
- Cleft Hand — also called split hand, lobster-claw hand or ectrodactyly — is characterized by shortened or missing central fingers. It can also occur in the foot.
- Polydactyly — and extra digit — is one of the more common malformations, usually affecting the thumb.
- Syndactyly — abnormal linkage between adjacent fingers — is most common between middle and ring fingers. The effect is referred to as “simple,” only the skin and soft tissue, or “complex,” bridging of bones and nails.
- Trigger thumb or finger — thumb more commonly — is an abnormality of the flexor tendon, causing it to be constantly bent inward or downward. It is fairly easily repaired surgically.
- Symbrachydactyly — short fingers — can vary in severity.
- Thumb hypoplasia — a malformation of the thumb — can also vary in severity.
Generally, if surgical repair of these conditions is a practical option, the surgery is done after six months to two years of age.