Reports Dutch French Case Discussions 1. Introduction Achondroplasia is the best known type of dwarfism. Typical are a normal length of the trunc, but short and heavy extremities, a lumbar hyperlordosis with horizontalization of the sacrum, a decreased flexion of the hips, and a decreased muscle tone.
Neurological abnormalities are frequent and mainly caused by a stenosis of the spinal canal.
A premature synostosis of the growth centers of the vertebrae and the posterior arc provoke a thickening of the lamina, a shortening and thickening of the pedicles, and a smaller vertebral height. The spinal canal is narrowed, as well in antero-posterior as in transverse direction. The stenosis can be cervical, lumbar or at both levels. Symptomatology of lumbar spinal stenosis is mainly prominent in the adult, but also in the adolescent neurological compromise can exist. 1 An eleven year old boy with achondroplasia complained of low back pain irradiating in the legs, after a minor trauma.