&NA;Intraventricular and intra‐axial lesions can be reached through a transsulcal approach, avoiding the more extensive cerebral tissue damage that may result from a conventional cortical incision. The sulci of five cadaver brains fixed in formalin solution were dissected using the operating microscope. The brains were photographed for surface mapping and x‐rays to demonstrate underlying ventricular relationships were taken. The brains were then coronally sectioned to characterize anatomical relationships between sulci and deep brain structures. Three important sulci were identified and thoroughly characterized with respect to surface relationships, average depth, and underlying structures that can be readily approached. Surgical application of these findings is discussed. (Neurosurgery24:651‐654, 1989)