Answer for BIR CoW 05 Oct 2025
TMJ anterior disc dislocation
Findings
Anterior disc dislocation in closed mouth view with partial recapture during open mouth view on right side Right mandibular condyle articullar surface appear flattened and irregular with STIR hyperintensity - secondary osteoarthritis
Discussion
Disk location is of prime cause of TMJ dysfunction It is important for the radiologist to detect early MR imaging signs of dysfunction, thereby avoiding the evolution to its final irreversible phase that is characterized by osteoarthritic changes such as condylar flattening or osteophytes The most frequent cause of TMJ dysfunction is internal derangement, which is defined as an abnormal relationship of the disk to the condyle Precise localization of the disk is very important in the diagnosis of TMJ internal derangement and can easily be achieved with MR imaging using closed and open mouth views Direct sign Abnormal disk morphologic features (Crumpled,Rounded,Flat,Perforated) Abnormal disk displacement in closed-mouth position - Anterior displacement -More frequently observed -Posterior displacement -Rare -Lateral or medial displacement Abnormal disk movement in open-mouth position Anterior disk displacement with reduction Anterior disk displacement without reduction Stuck disk (disk remains fixed) Osteoarthritic changes of the condyle (Flattening,Osteophytes,Erosion,Sclerosis) Indirect signs Large amount of joint fluid (joint effusion) Increased thickness of LPM attachments Rupture of retrodiskal layers When the mandible is in the closed-mouth position, the thick posterior band of the meniscus lies immediately above the condyle near the twelve o’clock position Anterior dislocation is considered to be present if the angle between the posterior band and the vertical orientation of the condyle (the twelve o’clock line)—the angle ofdisplacement— exceeds 30° Posterior dislocation is considered to be present if the angle between the posterior band and the vertical orientation of the condyle (the twelve o’clock line)—the angle ofdisplacement— exceeds 10° Treatment option: Meniscoplasty,meniscectomy,total joint replacement
Findings
Anterior disc dislocation in closed mouth view with partial recapture during open mouth view on right side Right mandibular condyle articullar surface appear flattened and irregular with STIR hyperintensity - secondary osteoarthritis
Discussion
Disk location is of prime cause of TMJ dysfunction It is important for the radiologist to detect early MR imaging signs of dysfunction, thereby avoiding the evolution to its final irreversible phase that is characterized by osteoarthritic changes such as condylar flattening or osteophytes The most frequent cause of TMJ dysfunction is internal derangement, which is defined as an abnormal relationship of the disk to the condyle Precise localization of the disk is very important in the diagnosis of TMJ internal derangement and can easily be achieved with MR imaging using closed and open mouth views Direct sign Abnormal disk morphologic features (Crumpled,Rounded,Flat,Perforated) Abnormal disk displacement in closed-mouth position - Anterior displacement -More frequently observed -Posterior displacement -Rare -Lateral or medial displacement Abnormal disk movement in open-mouth position Anterior disk displacement with reduction Anterior disk displacement without reduction Stuck disk (disk remains fixed) Osteoarthritic changes of the condyle (Flattening,Osteophytes,Erosion,Sclerosis) Indirect signs Large amount of joint fluid (joint effusion) Increased thickness of LPM attachments Rupture of retrodiskal layers When the mandible is in the closed-mouth position, the thick posterior band of the meniscus lies immediately above the condyle near the twelve o’clock position Anterior dislocation is considered to be present if the angle between the posterior band and the vertical orientation of the condyle (the twelve o’clock line)—the angle ofdisplacement— exceeds 30° Posterior dislocation is considered to be present if the angle between the posterior band and the vertical orientation of the condyle (the twelve o’clock line)—the angle ofdisplacement— exceeds 10° Treatment option: Meniscoplasty,meniscectomy,total joint replacement
Note:
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
If you feel you have answered rightly but cannot find your name in the above list, please call 09551942599.
Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
If you feel you have answered rightly but cannot find your name in the above list, please call 09551942599.
Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!