Precise measurements with the Vanguard Motion Analyzer were made to determine the position of the pineal gland as shown on the Polaroid displays of 145 normal [human] scans. The relatively midline positions of the gland are expressed in terms of a percentage shift of the pineal gland normalized to the calvarial diameter. The range of the percentage shift of the gland in these 145 normal cases is defined by a mean value of 0.8%, SD 0.6%. More than 99% of normal computed tomography scans can be expected to show a percentage shift of 2.6% or less.