children s health issues
Missing or Incompletely Formed Limbs
Introduction
Limbs can be missing, deformed, or incompletely developed at birth. Birth defects, also called congenital anomalies, are physical abnormalities that occur before a baby is born. "Congenital" means "present at birth." (See also Introduction to Birth Defects of the Face, Bones, Joints, and Muscles .) Limbs may form abnormally. For example, bones in the hand and forearm may be missing because of a genetic defect (see Overview of Chromosome and Gene Disorders ), or sometimes part or all of a hand or foot may be missing. Normal development of a limb can also become disrupted in the womb. In amniotic band syndrome, limbs develop abnormally when they are constricted by thin strands of tissue from the amniotic sac (the sac that holds the amniotic fluid surrounding the developing fetus in the womb). Abnormalities of the limbs can also be caused by a Overview of Infections in Newborns or a Abnormalities of the arms and legs may occur in a horizontal fashion (for example, if the arm is shorter than normal) or in a lengthwise fashion (for example, the arm is abnormal on the thumb side—from the elbow to the thumb—but normal on the little finger side). A child who has one birth defect of the limbs is more likely to have another abnormality. 