Techniques are described to aid in the recognition and clinical use of lateral echoes in the echo-encephalogram. Overlays of enlarged echo-encephalograms on plastic sheets were superimposed on coronal sections of brain to identify the source of reflections from normal structures and lesions. Echoes were seen to arise from interfaces of cerebrum and cerebrospinal fluid, interfaces of gray and white matter, and from some tumors. Premortem and postmortem echo-encephalograms were compared with each other, with regional cerebral structures, and with radiographic features. Projection of the image of a coronal section of normal brain to the oscilloscopic screen allowed lateral reflections to be seen on a background of corresponding cerebral structures.