Causes of Congenital Hand Deformities
This occurs when parts of the body stop developing while the baby is in the womb, causing either a complete absence of a part of the body, such as the hand, or a missing structure, such as part of the arm bone. In the case of the complete missing part, surgery is not indicated. These children may be introduced to prosthetic devices early in their childhood. Types of this classification include, but are not limited to:

Radial clubhand
A radial clubhand is a deformity that involves all of the tissues on the radial side (thumb side) of the forearm and hand. There may be shortening of the bone, a small thumb, or absence of the thumb. Deformities of the wrist are usually operated on around 6 months of age.

Ulnar clubhand
An ulnar clubhand is less common than a radial clubhand. This deformity may involve underdevelopment of the ulnar bone (the bone in the forearm on the side of the little finger), or complete absence of the bone.