[Restrictions on opening of the mouth caused by extra-articular inflammation]

Recent views concerning the physiopathological aspects of restrictions on opening of the mouth attributable to extra-articular inflammation are examined. Stress is laid on the importance of psychological factors related to joint function and various organs and apparatuses that interferere with such function by reflex action via the brain. Instances of extra-articular inflammation limiting opening of the mouth are listed, with particular reference to primary and secondary myositis and myositis ossificans. Inflammation may also supervene in osteodysplasia, granuloxanthomatous hyperdysplasia of the maxillary bones, while opening of the mouth may be restricted by fibrosis of the muscles used in mastication due to protracted immobilisation, as in ankylosis of the T.M.A. Lastly, the way in which inflammation accompanying diseases of the salivary glands, dysembryoplasia, and jaw and mouth cavity neoplasia may prevent proper opening of the mouth is explained.