Growth of Human Nervous System. II. Indices of Relation of Cerebral Volume to Surface in Developmental Period

Abstract

The estimation of the area of the human cerebrum has become a matter of considerable interest since the mass of the cerebral cortex is closely related to the surface area of the brain.This subject has been investigated by a quantitative study of 20 brains ranging in age from the fourth (lunar) month of prenatal life to the close of the fifth decade and in volume from about 5 cc. to over 1000 cc. The method of measuring surface area is described in other papers1, 2 and the volume was determined by the displacement method. Various indices of the relation of cerebral volume to surface are shown in Table I and in Fig. 1. In both the table and the figure the observations are arranged in order of cerebral volume.Column (b) of the table and panel (A) of Fig. 1 show the index of “total” surface area divided by cerebral volume (surface in sq. cm., volume in cc.). The index drops slowly at first, until the cerebrum has a volume of nearly 100 cc. (in the eighth lunar month), and shows practically no regular trend of...