Case History: A 24-year-old female presented with complaint of pain during chewing with locking of jaw, more on left side, and clicking sound while opening the mouth for two months.
Pain was on and off initially but increased in severity and duration in last 15 days
Figure 1. Plain T2 and T1 weighted MRI images. Left articular disc appears crumpled, irregular, and anteriorly displaced and lies below articular eminence. Minimal left temporomandibular joint effusion is noted. Mild thickening of lateral pterygoid is noted involved at its attachment.
Figure 2. Plain T2 and T1 weighted MRI images. On open mouth maneuver, there is no evidence of reduction of disc. No evidence of secondary cartilaginous or osseous changes are noted at present.
Figure 3. Plain T1 and T1 FATSAT MRI images. Maintenance of normal morphology of disc with normal reduction on mouth opening maneuver.
Figure 4. Coronal T1 weighted MRI image. Coronal MRI images allowing comparison of degeneration involving bilateral temporomandibular joints show mild anterior displacement of right sided articular (forming 40 degree angle with vertical line drawn from condyle of mandible).
When the jaw is opened >10 mm (measured between upper and lower incisors), a click or pop is heard, or a catch is felt, as the disk pops back over the head of the condyle.
On contrast-enhanced MRI, left articular disc appears crumpled, irregular, and anteriorly displaced, and lies below articular eminence.
Temporomandibular joint (TMJ) disorders are the main cause of chronic facial pain and disability.
Anterior disc displacement (ADD) is one of the major findings in TMJ internal derangement.
The most common complaints are pain and decreased mouth opening (normal inter-incisal distance is 35-50 mm).
Wilkes Classification of Internal Derangement of TMJ
State-of-the-art MRI techniques allow analysis of disc position in both sagittal and coronal planes, dynamic assessment of condylar translation, and disc movement during opening and closing of the mouth.
