Method of obtaining<unk> <unk>  is a lateral radiographic<unk>  of skull principally used for<unk> ing mastoid cells. The central beam of X-rays passes from one side of the head and is at angle of 25° caudad to radiographic plate. This angulation prevents overlap of images of two mastoid bones. Radiograph for each mastoid is taken separately. The<unk>  serves as an alternative<unk>  to the Law projection which uses a 15 degree angle of patient's face toward the image receptor and a 15 degree caudal angulation of the CR to achieve the same result, a lateral mastoid air cells<unk>  without overlap of the opposite side. Ear(pinna) under examination can be taped forward to avoid cartilage shadow around mastoid. Older editions of Merrill's positioning books will have detailed explanation of these and other mastoid positions. Newer texts often omit this because of the rarity of this exam in lieu of computed tomography studies. __TOC__
Schuller's view
Waters' view
Caldwell's view
Fowler's position
Papworth method
Talairach coordinates
De Finetti diagram
Breslow's depth