Temporomandibular joint disorders (TMD) often show muscular disorder, internal derangement and degenerative change of articular surface of the condyle. It is important to choose adequate diagnostic method for obtaining data for the diagnosis and treatment. Magnetic Resonance Imaging (MRI) has some advantages, because it shows good resolution image for the soft tissue and it is not invasive to the human body. We have performed serial research about the retrodiscal tissue of the TMJ according to the progress of the disease, using T2 weighted image, since 2002. In this study, we applicated resized observation area to compare signal intensity between the retrodiscal tissue of the TMJ and cerebral gray matter, using T2 weighted image.