Figure 2.29. This infant with diastrophic dysplasia presents the marked narrowing of the chest, the short limbs and the typical "hitchhiker" thumbs (hyperex-tensible and hyperabductable). In this autosomal recessive condition there is disproportionate dwarfism (abnormal shortness of die proximal parts of die limbs), club feet, and widening between the first and second toes ("sandal" sign). The big toes are abducted.
Figure 2.30. This figure is a close-up of the typical "hitchhiker" thumbs in the same infant with diastrophic dys-plasia. The "hitchhiker" thumb is caused by hypoplasia of the first metacarpal, and the long axis of the digit is oriented almost horizontally in relation to the palm. The thumb is retroflexed with hypoplasia of the thenar musculature. Radiographic examination of the long bones in these infants demonstrates spreading of the metaphyses and delayed closure and deformation of the epiphyses.
Was this article helpful?