Sexual dimorphism of corpus callosum occurs in human foetuses.

ABSTRACT

Sexual dimorphism in human corpus callosum is controversial, and only a limited number of studies have been done on foetuses. Corpus callosum of 50 foetal brains, 25 male and 24 female were studied however, one foetus with undifferentiated sex, was excluded from the present study. The crown rump length (CRL) and the brain weight of these foetuses ranged from 5 to 39 cm and 10 to 550 gm. Brain was divided into two equal halves by median section after fixation. The length of the corpus callosum, pre-callosal and post-callosal lengths, were measured on the medial aspect of each cerebral hemisphere. The thickness of splenium was measured in the sagittal section. The brain weight increased with increase in the CRL length in all the foetuses. The average length of the corpus callosum was more in males than in females. The z test value was 1.3871, which is not significant. The thickness of splenium was more in females than male. The z test value was 2.28, which is highly significant. Sex difference was not observed in any of the other parameters.