Dilatation of cerebral ventricles in patients with rheumatoid vertical atlanto-axial subluxation.

Twenty-four patients with seropositive rheumatoid arthritis, 12 of them with anterior atlanto-axial subluxation alone and 12 with vertical atlanto-axial subluxation, were examined by echo-encephalographic measurement of the width of third and lateral cerebral ventricles. The 12 patients with anterior atlanto-axial subluxation showed normal values for the third and the lateral ventricles. Ten of the 12 patients with vertical atlanto-axial subluxation had increased width of third and lateral ventricles, indicating hydrocephalus.