Figure 8. a, Sagittal and b, coronal MR images (770/27) of a normal TMJ with the jaw in an open position. Note the bow-tie shape of the disk in the sagittal projection. 1, Mandibular head; 2, articular eminence; 3, disk (3a, anterior band; 3b, intermediate zone; 3c, posterior band) ; 4, bilaminar zone; 5, lateral pterygoid muscle.