Limb malformations
Introduction
The overall incidence of congenital limb malformations is
1 in 500 to 1500 live births. The manifestation vary from minor
anomalies to severe crippling. The defects may be isolated
or found with additional malformations. Radial and central
ray maformations, amelia and rudimentary limb show a strong
association with other anomalies. Severe malformations can be
diagnosed prenatally. Syndactyly and polydactyly are the most
common abnormalities seen in general population.
Etiology
- genetic
- enviromental — teratogenic agents such as certain drugs,
maternal diabetes, congenital varicella infection.
Phocomelia is the most common limb malformation associated
with teratogenic Thalidomid (note: Thalidomid was prescribed
to pregnent women as a sedative releaving nauzea in the late
1950 and early 1960).
- unknown
Important syndromes associated with limb malformations:
- Trombocytopenia — absent — radius (TAR)
syndrome: autosomal recessive, radial aplasia and bleeding
disorders
- Fanconi anemia: autosomal recessive, variable limb
malformations, short stature, microcephaly, pancytopenia occurs
in childhood, high risk of leukemia
- Holt — Oram syndrome (hand — heart):
autosomal dominant, variable bilateral but often assymetrical
limb malformation, heart defects (atrial septal defects in particular)
- VACTERL
see VACTERL
- Femoral hypoplasia —
unusual facies:
often associated with maternal diabetes, unusual face with recessed chin,
long filtrum and small nose, short femur
- Tibial hemimelia: autosomal dominant
- Femur — ulna syndrome
-
Tibial hemimelia
Terms derived from Latin or Greek which are used in common
praxis are familiar, but the meaning is innacurate and often
misused.
- Ectromelia —
complete or almost complete
absence of one or more limb. The limb is completely absent
or ends in one or more imperfect digits or in a stump without any digits.
- Phocomelia —
seal limb (greek phoke means a seal).
The hand or feet of usual size and often completely normal are
attached directly to the shoulder/hip or to abbreviated arms and legs.
- Hemimelia —
half limb. The forearm or the leg,
but particularly the hand or foot, is lacking or it represented
by only some rudimentary parts. There is a stump without any
sign of hand or foot or a stump ending in one or more imperfect digits
- Peromelia —
meaning a malformed limb (limb stump),
a vague clinical term
- Amelia —
absence of an entire limb
- Meromelia —
partial absence of a limb
- Acheiria —
absence of one or both hands
- Apodia —
absence of one or both feet
The involvement of individual bone ranges from complete aplasia
to partial aplasia and hypoplasia (teratogenic sequence).
Precise classification on anatomical basis (Swanson)
- Type I. — failure of formation of parts
- Type II. — failure of separation
- Type III. — duplication
- Type IV. — overgrowth
- Type V. — undergrowth
- Type VI. — constriction (amniotic) band syndrome
Type I., subclassificaton of defects
- Terminal — absence of limb segments below a certain
point with relative preservation of the more proximal segments
- Intercalary (interposed) — absence of proximal or
middle segments when the distal structures are present even if malformed
- Transverse — involves the full width of the limb
- Longitudinal — defects paralleling the long axis of the limb
- Preaxial — involvement on the radial (thumb) or tibial (big toe) side
- Postaxial — involvement on the ulnar (little finger)
or fibular (5th toe) side
- Central — involvement of the middle rays
Most limb deficiencies can be classified into one of the following groups this way:
- Terminal transverse
- Terminal longitudinal
- Intercalary transverse (phocomelia)
- Intercalary longitudinal
Pictures
Upper limbs defect:
Upper limbs defect, Macro, autopsy (73654)
Upper limbs defect, Macro, autopsy (73655)
Upper limbs defect, Macro, autopsy (73656)
Upper limbs defect, Macro, autopsy (73657)
Malformation of the tibia, polydactyly:
Malformation of the tibia, polydactyly, Macro, autopsy (73738)
Malformation of the tibia, polydactyly, Macro, autopsy (73739)
Malformation of the tibia, polydactyly, Macro, autopsy (73740)
