Medical Description of Hand Differences
There are a number of reputable medical websites that offer information on Hand Difference. Some are written for parents and others are for clinicians.
Adactyly: Absence of all fingers and thumb
Amniotic Band Syndrome (ABS) or Constriction Ring Syndrome: Constriction of fingers or thumb by amniotic band(s)
Aplasia: Absence of specific bones and parts
Arthrogryposis: “Curved” stiff joints