<unk>  is a congenital defect which affects the formation of the radius bone in the arm. The radius is the lateral bone (thumb side) which connects the humerus of the upper arm to the wrist via articulation with the carpal bones. A child born with this condition has either a short or absent radius bone in one or both of his or her arms.<unk>  also results in the thumb being either partly formed or completely absent from the hand, which can result in difficulties performing activities of daily living.<unk>  is connected with the condition VACTERL association, under the 'L' for limb malformations.<unk>  is not inherited. The cause for<unk>  is unknown, but it widely believed to occur within the first ten weeks of gestation.
Radial aplasia
Condylar hypoplasia
Congenital clasped thumb
Thumb hypoplasia
Radial dysplasia
Oligodactyly
Synpolydactyly
Syndactyly