The Width of the Third Ventricle in Neurosurgical Patients with Extrapyramidal Movement Disorders

The width of the posterior part of the third ventricle was measured at peroperative encephalography in 105 patients with extrapyramidal movement disorders, undergoing thalamotomy. The average width was found to be 8.9 mm (true dimensions), which means that it was found to be wider than earlier published average widths of the third ventricle in ‘normal’ brains. The width was found to be larger in men than in women. The immediate result of the operation was better in patients with small than in those with wide third ventricles. A normal variation in the width of the third ventricle from day to day of up to 2 mm in the same individual was found.