When establishing borders microscopically and cytoarchitectonically, the volume of the nucleus caudatus (NC) has been measured in human brains from persons of various sex and age (21 persons and 27 hemispheres). The NC volume varies greatly in some persons and it is connected neither with the brain mass, nor with the sex and age. Difference between the extreme variants is more than twice as great. Great morphological differences are supposed to demonstrate a corresponding individual functional specificity. The extreme variants occur rather seldom, cases with less range of differences prevalence. The NC asymmetry is revealed, with the right-sides (5 cases) or left-sided (1 case) prevalence. Very great individual peculiarities are revealed in relations of the form and the extent of various components of the NC: head, body and tail, as well as in the peculiar ending of the latter. Owing to the data obtained, it is necessary to revise the competency of the view on proportional dependence between the external and internal cerebral structures which make the base for using stereotaxic atlases of the human brain, since the existence of the extreme variants creates a real threat of complications in these cases at various operative interventions relying upon the reference points available.