Krukenberg's hand

Krukkenberg's hand is the medical term for a congenital hand structure in some children. This pathology manifests itself in the presence of an extra row of fingers on one or both hands. Cases where all four metacarpal bones have an extra row are extremely rare and occur in less than 0.02% of all cases. An additional middle first and/or second metacarpal is commonly found. However, they can be connected to other finger bones, which leads to short