Growth of Human Nervous System. III. Relations between Cerebral Surface,Volume and Length

Abstract

The human cerebrum, excluding its ventricular system, is a solid: and it is possible by the study of its measurements to determine to what degree, if any, the growth of this structure follows the usual geometric laws of the interrelation of dimensions of solids with simple and regular form.

If these dimensions approach the geometric rules of dimensionality, it is to be expected that the following relations may be approximated:

and also the converse expressions. In the above general formulae CV is cerebral volume, CL cerebral length, and CS cerebral surface. The k's are constants to be empirically determined, and the other lower case letters represent powers also to be empirically determined. For objects of simple and regular geometric form it is to be expected that a will approach 3; b, 2; and c, 2/3.

We have tested these assumptions by fitting curves for several of these dimensions as determined from a series of 20 cerebri, ranging from about 5 cc. to over 1,000 cc. in volume and from slightly less than 4 fetal or lunar months to about 50 years in age. 1 All curves were fitted by the method of average logarithms. 2