Internal derangement of the temporomandibular joint

Internal Derangement is one of the most common disorders of the Temporomand ibular joint. It is defined as an abnormal anatomical relationship between the discus articularis and the other structures of the temporomandibular jo int. More than 2/3 of patients with clinical symptoms of the temporomandibu lar joint have an internal derangement. The most frequent finding in intern al derangement is an anterior dislocation of the disc with reduction after mouth opening. In more severe cases a complete anterior dislocation is foun d without reduction of the disc. Internal derangement is a risk factor for developing osteoarthritis with remodeling of the condylus and the fossa man dibularis. The most important modalities of radiologic diagnosis are arthro graphy, CT and MRI. The diagnosis of craniofacial dysfunction has been impr oved dramatically by modern imaging techniques, which have become essential tools for primary diagnostic and evaluation after conservative or surgical therapy. MRI has become the gold standard.