Fig. 48-4. A, Parotid sialogram in vivo. Iodized oil has been injected through the parotid duct. B and C, The temporomandibular joint with the mouth closed (head in the mandibular fossa) and with the mouth open (head on the articular tubercle). The black oval area posterior to the head of the mandible is the external acoustic meatus. (Courtesy of Mr. John A. Hill, Birkenhead, England.) Click for high resolution image.