ON THE PROPORTIONS BETWEEN SOME AREAS OF THE FIRST CERVICAL SEGMENT OF THE SPINAL CORD OF PRIMATES

ON THE PROPORTIONS BETWEEN SOME AREAS OF THE FIRST CERVICAL SEGMENT OF THE SPINAL CORD OF PRIMATES

DEPARTMENT OF ANATOMY, THE JOHNS HOPKINS UNIVERSITY SCHOOL OF MEDICINE, BALTIMORE, MARYLAND

Abstract

It has been generally supposed that the dorsal funiculi occupy a relatively larger part of the highest segments of the spinal cord in man than in any other primate. We have taken planimetric measurements of the total area of the cord, dorsal funiculi, and total gray in the uppermost segments of the spinal cord of a wide variety of primates. Our results indicate that the largest values for the proportions dorsal funiculi/total white matter and dorsal funiculi/ventrolateral funiculi are found in gorilla, chimpanzee, and orang, rather than in man. Moreover, man has, on the average, smaller dorsal funiculi in relation to either the total white or ventrolateral funiculi than any of the three great apes.