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August 1966

Vertebral Artery Obstruction With Basilar Impression: An Intermittent Phenomenon Related to Head Turning

Author Affiliations

From the departments of neurology, radiology, and medicine of the Bowman Gray School of Medicine of Wake Forest College, Winston-Salem, NC.

Arch Neurol. 1966;15(2):211-214. doi:10.1001/archneur.1966.00470140101014

OF THE many hypotheses proposed to explain the signs and symptoms of basilar impression, two of the most popular are based on the fact that basilar invagination diminishes the volume of the posterior fossa. One hypothesis holds that symptoms are related directly to pressure by the surrounding bony structures. The other states that osseous compression causes a reactive arachnoiditis which interferes with the flow of cerebrospinal fluid. The proponents of the latter conclude that symptoms are due to the combined effects of intrinsic hydrostatic forces and external compression.

We recently evaluated a patient who had basilar impression. His symptoms and signs were made worse when he turned his head to the right, which suggested to us that vertebral artery flow might be affected by change of head position on a basis similar to that noted during postmortem investigations.1-3 Cineangiography enabled us to demonstrate obstruction to flow in the left