Congenital means "present at birth." A congenital hand difference is a variation in the normal formation of the hand that occurs when the fetus is in the womb.
Differences in a child’s physical appearance – such as hand differences – are noticeable at birth, which can be distressing to the parents. In some cases, feelings of anger and guilt develop, especially in the mother, who may blame herself for some "failure" during the pregnancy. Parents may also become angry with health care providers for not detecting the problem during routine prenatal care. In fact, no one is at fault. Most hand differences are not hereditary (do not run in families) or preventable, and many cannot be detected before birth.
Although congenital hand differences are generally noticeable at birth, the doctor may take X-rays to determine the extent of bone/tissue involvement; for example, to see if the difference is simple or complex.
Hand differences can be grouped based on the type of difference present. These general categories include:
Specific congenital hand differences include the following:
Syndactyly is the most common congenital hand difference. The word syndactyly is derived from the Greek syn, which means together, and daktylos, which means digit (finger or toe). Syndactyly is a condition in which the fingers are fused together or the webbing between the fingers extends farther up the fingers than normal. The condition can be simple, with only skin shared by the fingers, or complex, with shared bone, nerves, blood vessels and/or other tissues. Syndactyly is usually treated by surgically separating the fingers. Often skin grafts are necessary, as there may be deficient skin to provide coverage for two fingers. Casting or splinting, as well as physical therapy, also may be recommended – especially in complex cases – to help maximize hand function post operatively.
Polydactyly is the presence of more than five digits (poly means many). The extra finger or thumb may be attached only by skin or nerves, or it may have normal parts and be attached to a joint or an extra bone in the hand.
Ulnar polydactyly, the most common type, refers to an extra finger or part of a finger that develops on or near the little finger of the hand. (Ulnar refers to the ulna, the larger of the two bones of the forearm. The ulna is on the same side of the arm as the little finger.) Polydactyly can be treated by surgically removing the extra digit and reconstructing the remaining digit.
Thumb (Radial) Polydactyly
Thumb (Radial) Polydactyly refers to the presence of multiple thumbs on one hand. This condition can be treated by removal of the additional digit and surgical reconstruction of the remaining thumb.
Radial Club Hand
Radial club hand refers to a condition in which the radial (referring to the radius, the smaller bone of the forearm) or thumb-side of the arm is malformed, causing a shortening and curving of the forearm and giving the appearance of a J-shaped club. The thumb may be small or completely absent.
With a shortened forearm, people with radial club hand may have difficulty performing tasks that require two hands. This difference can occur in one (unilateral) or both (bilateral) arms.
Treatment depends on the functional abilities and needs of the child, and may include limb manipulation and stretching, splinting or casting, and/or surgery.
The term cleft hand actually refers to a group of congenital hand differences in which the fingers or parts of fingers in the center of the hand are missing, leaving a V-shaped space or indentation (called a cleft). Other differences, particularly syndactyly and polydactyly, often occur at the same time. There are many variations of cleft hand.
Typical cleft hand is characterized by a gap in the palm and the absence of the middle finger or fingers. Cleft hand can be unilateral or bilateral. (There are patients with a family history of clefting in both hands and feet.) In typical cleft hand, the hand is almost normal in size, and the arm bones are usually normal.