OBJECTIVETo investigate the MR image features of TMJ coronal structures.

METHODS28 TMJs from 15 cadavers dipped in formalin over 1 year were included. Their mandibles were fixed at intercuspal position when TMJs oblique coronal MR scan was taken. Baseline was draw on the oblique coronal imaging along the ramus of mandible through its center. The corresponding dimensions and areas were measured with electronic ruler.

RESULTSThe dimensions were in accordance from large to small as: lateral-medial dimension of fossa, lateral-medial dimension of condyle, medial dimension of fossa, medial dimension of condyle, lateral dimension of condyle and lateral dimension of fossa. Three significant co-relative relationship were found: the lateral dimension of condyle with lateral dimension of fossa, the medial dimension of condyle with medial dimension of fossa, and the lateral-medial dimension of condyle with lateral-medial dimension of fossa. CV of lateral dimension of fossa was higher than that of lateral and medial dimension of condyle, and then all the three were higher than other dimensions. The size of the area of joint space shown on oblique coronal imagings was positively related to that of the area of coronal disc imagings.

CONCLUSIONSignificant co-ordinate relationship of condyle and fossa of TMJ coronally was existed, and the condyle position to fossa lateral-medially varied in great.