Hirtz' projection

(also called the submentovertical projection), conventional radiographic projection of the sinonasal cavities. The vertex is placed against the table top, with the neck in extension; the Frankfort plane should be parallel to the film. The central ray is centred between the angles of the jaw. This projection gives a good view of the mandibular arch and condyles, the skull base, sphenoid sinus and the posterior ethmoid cells.

RH