United States. Surgeon-General's Office, American Roentgen Ray Society · New York : Middleditch · leaf 216
f the angle finder is placed opposite theglabella, the left arm passing across the external auditorymeatus, the right arm extending upwards alongside thecone and representing the direction of the principal ray.The cone is now brought in to alignment with the arm ofthe finder and brought down on the… … Fig. 9. Adjustment for exposure of accessory sinuses In the posterior-anterior direction. 209
