[TA] a dilation of the subarachnoid space rostral to the basilar pons and ventral and caudal to the mammillary bodies where the arachnoid membrane stretches across between the two temporal lobes over the base of the diencephalon.interpeduncular fossa SYN: cisterna interpeduncularis [TA], basal cistern, cisterna basalis, cisterna cruralis, Tarin space.
