Abstract
We investigated the jaw opening degree and jaw opening pathway on 138 normal subjects and 104 abnormal subjects to make an objective basis of the jaw opening pathway as one of the examinations of stomatognathic dysfunction. As examining the terminal hinge opening pathways we distinguished the initial phase in which the movement of the condyle was considered mainly to be rotation from the second phase in which the jaw moved to the maximal opening position after the initial phase. Then we classified jaw opening pathways of all subjects into seven patterns by the presence of the mandibular deviation in each phase described above and near the maximal opening position. As a result, half of the normal subjects belonged to pattern A, 70% of those with pain and temporomandibular joint noise to pattern B and, 50% of those with the limitation of the jaw movement showed linear opening and 30% with the limitation belonged to pattern D.
