Limb deficiencies are skeletal problems that result in shortened, missing, or malformed limbs. A limb deficiency can be a result of a congenital factor (teratogen, maternal disease, or drug action) or may occur as a result of an accident or injury (amputation). By far the more common form of limb deficiency is from a congenital cause, representing up to 70% of pediatric cases. More often than not, it is the upper extremities that are effected. Missing or malformed thumbs, fingers, and hands are the most common form of congenital malformation. Acquired limb deficiencies (those present after birth) in children is most often from an accident or injury. A smaller percentage of limb deficiencies are a result of amputations due to cancer, infections, and burns.
The etiology of most congenital limb deficiences is unknown. Some suspected causes include infection, drugs, radiation, diseases of the mother, and exposure to toxic substances. Probably the most publicized agent associated with limb deficiences is thalidomide, a sedative used to reduce morning sickness. Happily, this drug is no longer used after researchers directly linked it to a startling increase in multiple limb deficiences during the late 1950s and early 1960s. In a small number of cases, limb deficiences have been linked to specific genetic conditions such as Trisomy 13 and 18.
The specific type and degree of the limb deficiency is related to the timing of the event that disrupts normal fetal development. The earlier in fetal life the baby is exposed to the agent, the more extensive the effect on the developing skeletal and muscular structures. In some instances, the entire development of the limb may be arrested; in others the process is interrupted and results in a malformation.
The effects of a missing or malformed limb depend on the specific limb effected, the extent of the malformation (or deletion), and the ability of intervention personnel to fit the person with a prosthesis (substitute body part).