Case Of the Week (COW) 03 Feb 2013
Answer:
Complete anterior displacement of disc without reduction: TMJ internal derangement with secondary degenerative changes in mandibular condyle.
Findings:
The head of the condyle is posteriorly positioned in the glenoid fossa. The posterior thick band of the disk is completely anterior to the condylar head. Upon opening of the mouth, the condyle moves to a point just inferior to the articular eminence. Rather than recapturing the disk, it pushes the disk anteriorly and does not regain the normal relationship.
Discussion:
Displacements of the disk in the anterior ,anteromedial, or anterolateral direction are the most common findings observed when interpreting MR images of patients with clinical signs and symptoms of internal derangement In the sagittal plane the disk is noted to be displaced when its posterior band is anterior to the condyle. Disk displacement may be complete or partial. In complete disk displacement, the entire mediolateral dimension of the disk is displaced anterior to the condyle. In partial disk displacement, only the medial or lateral part of the disk is displaced anterior to the condyle. MR images obtained at maximum mouth opening determine whether the disk displacement reduces. In displacement with reduction the disk position normalizes during jaw opening. In disk displacement without reduction the disk remains anterior to the condyle in all mandibular positions.
Contributed By:
Dr. Karunakaran M Kalathi, Dr. Arun Chelladurai
Consultant Radiologists, Aarthi Scans, Thirunelveli
Answer:
Complete anterior displacement of disc without reduction: TMJ internal derangement with secondary degenerative changes in mandibular condyle.
Findings:
The head of the condyle is posteriorly positioned in the glenoid fossa. The posterior thick band of the disk is completely anterior to the condylar head. Upon opening of the mouth, the condyle moves to a point just inferior to the articular eminence. Rather than recapturing the disk, it pushes the disk anteriorly and does not regain the normal relationship.
Discussion:
Displacements of the disk in the anterior ,anteromedial, or anterolateral direction are the most common findings observed when interpreting MR images of patients with clinical signs and symptoms of internal derangement In the sagittal plane the disk is noted to be displaced when its posterior band is anterior to the condyle. Disk displacement may be complete or partial. In complete disk displacement, the entire mediolateral dimension of the disk is displaced anterior to the condyle. In partial disk displacement, only the medial or lateral part of the disk is displaced anterior to the condyle. MR images obtained at maximum mouth opening determine whether the disk displacement reduces. In displacement with reduction the disk position normalizes during jaw opening. In disk displacement without reduction the disk remains anterior to the condyle in all mandibular positions.
Contributed By:
Dr. Karunakaran M Kalathi, Dr. Arun Chelladurai
Consultant Radiologists, Aarthi Scans, Thirunelveli