Abstract:

Objective To understand the gyri shape of parietal lobe convexity in human brain. Methods The configuration of
gyri on the lateral surface of the parietal lobe of 60 formalinfixed cerebral hemispheres was observed by naked eyes, and
measured with vernier caliper.Results There was a protuberance on the convexity of parietal lobe, posterior to lower portion
of postcentral gyrus. The area of the protuberance was about 2cm×2cm to 45cm×45cm, 3cm above auricle. The protuberance
mainly consisted of the supramarginal gyrus, which was of various shapes arched superoposteriorly, or was a short gyrus dropped
superoposteriorly and inferiorly. When the protuberance more obviously protruded,the lower portions of the precentral and
postcentral gyri were pushed forwards and their upper portions were pushed backwards thus the whole shape of the precentral
gyrus looked and postcentral gyrus looked like “s” shape. Conclusion There is a constant protuberance in the parietal lobe
convexity which can be located from the structures inside and outside of skull.

Key words: Cerebral hemisphere, Parietal lobe, Supramarginal gyrus, Protuberance, Measurement, Human