Position of the medial internal capsular border in relation to third-ventricular width.

The position of the medial internal capsular border (lateral thalamic border) in relation to the width of the third ventricle is of considerable importance to stereotactic surgeons. Close estimation of its position from anteroposterior roentgenograms diminishes the possibility of multiple brain penetrations in an attempt to find it by electrophysiological methods. By correlating the position of the medial capsular border found by a stimulation technique, with the width of the third ventricle, in a series of 130 patients, reliable ranges of its position were obtained.