Ultrasound imaging of condylar motion: a preliminary report.

Studies of condylar motion within the temporomandibular joint have been going on for some time. These studies have used techniques that included direct viewing via x-rays, magnetic resonance imaging, and arthroscopy, as well as indirect measurements using axiographs, kinesiographs, photocells, and light-emitting diodes. These viewing and measuring methods have important disadvantages and shortcomings. Recent advances in ultrasound technology, used extensively in medicine, have been adapted to dynamic imaging of the temporomandibular joint in the near-sagittal plane. Preliminary results strongly suggest that condylar motion is curvilinear throughout its range of motion. No evidence was seen to support the notion that condylar motion occurs about a fixed axis or point at any time during movement. Additional improvements in ultrasound technology may allow further definitive studies, and it may become usable in diagnosing temporomandibular dysfunction and disease states in the near future.