Fig. 4. A. Schematic showing positioning for a lateral projection. (CR, central ray) B. Radiograph of a lateral projection. (a, orbital roof; b, frontal sinus; c, ethmoid sinus; d, anterior clinoid process; e, sella turcica; f, planum sphenoidale) (A; Rao VM, Gonzalez CF: Plain film radiography and polytomography of the orbit. In Gonzalez CF, Becker MH, Flanagan JC [eds]: Diagnostic Imaging in Ophthalmology, pp 1–7. New York, Springer Verlag, 1986)