Pineal Calculator

Ref. L6

In some 50% of normal adults, the pineal gland, a small midline structure of the brain, may contain an agglomerate of tiny calcifications totaling a few millimeters in size and which may be visible on standard X-ray films of the skull. An intra-cranial hematoma or a space-occupying lesion of some size would displace these calcifications in the opposite direction. 

Any displacement of the calcifications may therefore imply the presence of an underlying pathology that would, before the advent of computed tomography, justify a more aggressive procedure such as an angiography or a pneumo-encephalogram.

A displacement to the right or to the left may easily be determined on an antero-posterior X-ray of the skull by the use of any standard ruler. For determining any anterior or posterior displacement on a lateral view, the Neurological Institute of New York devised, early in the second half of last century this plastic ruler with a sliding component, much like the good old mathematical slide-rule.

See below the instructions printed on the back of the ruler.