group of nuclei located in the posterior hypothalamic area; the group consists of a large-celled lateral nucleus of the mammillary body and larger medial nuclei of the mammillary body, dorsal and ventral premammillary nuclei, and supramammillary nucleus; the first two form the elevation seen on the ventral aspect of the diencephalon, the mammillary body. SYN: nucleus corporis mammillaris lateralis [TA], nucleus corporis mammillaris medialis [TA], nuclei corporis mammillaris.