A comparative morphometric analysis of MRI brain tomograms of term ant preterm born children was conducted. Common morphometric indexes and a novel quantitative parameter, a coefficient of corpus callosum (kCC), developed with regard to prenatal cortex ontogenesis pattern were applied to the study in order to get objective structural characteristics of the brain. All these quantitative indexes display anatomical features of the preterm brain. Reduced values of corpus callosum coefficient at preterm born children are known to associate with altered proportion between its rostral and caudal segments. A threshold coefficient value was established to differentiate preterm brain from the term one and it has proven its statistical significance.