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Primary basilar impression

Orpha number ORPHA2285
Synonym(s) Bull-Nixon syndrome
Prevalence Unknown
Inheritance Autosomal dominant
Age of onset All ages
  • Q75.8
MeSH -
MedDRA -


Basilar impression is a radiologic criterion, characterized by an invagination of the craniovertebral junction into the skull, and a short neck with abnormal position of the head. The primary basilar impression is a rare form, described in about 100 patients during the 50s, for which autosomal dominant inheritance is likely. About half of the cases are asymptomatic, and in the other half patients may present with Horner syndrome, pyramidal syndrome or signs of syringomyelia (sensitive troubles, limb weakness).

Expert reviewer(s)

  • Dr Elisabeth ROBERT-GNANSIA

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