A transcranial radiographic examination of the temporal portion of the temporomandibular joint.

The temporomandibular joints of 20 human cadaver heads were examined by means of photography (gross anatomic images) and radiography (lateral oblique transcranial images), using the angle created by a line parallel to the Frankfurt horizontal and a line coinciding with the posterior slope of the most lateral (outermost) portion of the articular tubercle. This lateral eminence angle, made visible through an attached metal wire and a straight stick pin and pertaining to the outermost (zygomatic) portion of the eminentia, was about 45 degrees on both enlarged photographs and enlarged radiographs. There were no significant differences between the photographic and radiographic lateral eminence angles on the right and left sides. A more medially placed angle, yet pertaining to the lateral - and supposedly functional (protrusion) - portion of the glenoid fossa, was about 56 degrees on the right side and 51 degrees on the left side of the radiographic images. There were significant differences between the ipsilateral radiographic lateral and medial eminence angles. A separate decision-making analysis concluded that lateral oblique transcranial radiography is an effective, reliable, and inexpensive method for detection of bony changes in the lateral portions of the temporomandibular joints.