pediatrics
Congenital Limb Abnormalities
Limb deficiencies
Congenital limb amputations and deficiencies are missing or incomplete limbs at birth. The overall prevalence is 7.9/10,000 live births. Most are due to primary intrauterine growth inhibition, or disruptions secondary to intrauterine destruction of normal embryonic tissues. The upper extremities are more commonly affected. Congenital limb deficiencies have many causes and often occur as a component of various congenital syndromes. Teratogenic agents (eg,thalidomide,vitamin A) are known causes of hypoplastic/absent limbs. The most common cause of congenital limb amputations are soft-tissue and/or vascular disruption defects, such as amniotic band-related limb deficiency, in which loose strands of amnion entangle or fuse with fetal tissue. Limb deficiencies can be Longitudinal (more common) Transverse Longitudinal deficienciesinvolve specific maldevelopments (eg, complete or partial absence of the radius, fibula, or tibia). Radial ray deficiency is the most common upper-limb deficiency, and hypoplasia of the fibula is the most common lower-limb deficiency. About two thirds of cases are associated with other congenital disorders, including Adams-Oliver syndrome (aplasia cutis congenita with partial aplasia of the skull bones and terminal transverse limb malformations), Holt-Oram syndrome, TAR (thrombocytopenia-absentradius) syndrome, Fanconi anemia, and VACTERL (vertebral anomalies,anal atresia,cardiac malformations,tracheoesophageal fistula,renal anomalies andradial aplasia, andlimb anomalies) syndrome. In the most severe form of radial ray deficiency, the radius is absent, as in this patient. The hand is angulated and deformed. © Springer Science+Business Media This photo shows radial atresia of the right arm in a patient with VACTERL (vertebral anomalies,anal atresia,cardiac malformations,tracheoesophageal fistula,renal anomalies andradial aplasia, andlimb anomalies) syndrome. Image courtesy of CDC/Dr. James W. Hanson via the Public Health Image Library of the Centers for Disease Control and Prevention. This photo shows clubbing of the left foot in a patient with VACTERL (vertebral anomalies,anal atresia,cardiac malformations,tracheoesophageal fistula,renal anomalies andradial aplasia, andlimb anomalies) syndrome. Image courtesy of CDC/Dr. James W. Hanson via the Public Health Image Library of the Centers for Disease Control and Prevention. Intransverse deficiencies,all elements beyond a certain level are absent, and the limb resembles an amputation stump. Amniotic bands are the most common cause; the degree of deficiency varies based on the location of the band, and typically, there are no other defects or anomalies. The remaining cases are mostly due to underlying genetic syndromes such as Adams-Oliver syndrome or chromosomal abnormalities. With transverse or longitudinal deficiency, depending on the etiology, infants may also have hypoplastic or bifid bones, synostoses, duplications, dislocations, or other bony defects; for example, in proximal femoral focal deficiency, the proximal femur and acetabulum do not develop. One or more limbs may be affected, and the type of defect may be different in each limb. Central nervous system abnormalities are rare. 