Case presentation
Medical history: Female, 28 years old, left temporomandibular joint bouncing, opening limited temporomandibular joint oblique sagittal position MR:
Temporomandibular joint disorders
Temporomandibular disorders (TMD) is a general term for a group of diseases involving the temporomandibular joint and/or masticatory muscles that share some of the same associated clinical problems (e.g., pain, elasticity, mouth restriction, etc.). TMD includes disorders of temporomandibular joint and/or masticatory muscle pain, structural disorders dominated by disc displacement, and degenerative joint diseases.
pathogen
(1) Psychological factors; (2) oral factors (congenital development factors, wear and tear, tooth loss, poor chewing habits, caries and hard tissue disease, malocclusion deformity, iatrogenic injury, systemic factors) ;(3) metabolic factors; (4) immune factors; (5) joint overload, etc.
Clinical manifestations
Mandibular movement abnormalities: openness, opening abnormalities, arthrectosis; pain: motor pain; murmur: pop, broken, rubbing; headache; ear symptoms; neck symptoms; constitutional symptoms.
Composition of the temporomandibular joint
Temporomandibular joint composition: hard tissue: joint fossa, temporal bone joint nodules, mandibular condyles; soft tissue: articular discs, joint capsules, ligaments; chewing muscles: extrawinglytenthias, masseter muscles.
Temporomandibular joint anatomy
Lateral bitmap shows the relationship between the head of the condylar process in the temporomandibular joint and the base of the skull. The temporomandibular joint mainly includes the condyle, joint disc, mandibular fossa and joint nodules.
A lateral magnification of the temporomandibular joint shows the articular disc and its anterior, middle, and posterior bands, and the thinner part of the articular disc is called the medial band, so the articular disc is double concave. The articular disc divides the temporomandibular joint into two compartments, upper and lower. Note: The upper head of the extraterrilateral muscle attaches to the anterior band of the articular disc, and the lower head attaches to the condyle or condyle and the articular disc. The posterior margin of the posterior band is divided into two branches, with the upper branch attached to the posterior fossa of the lower jaw and the lower branch attached to the posterior border of the condyle of the lower jaw.
MRI scan
MRI scan sequence: flat sweep: oblique coronal position of closed and open mouth: the long axis of the scan line pituitary in the inner and outer diameter of the condyle, T1WI+FS, T2WI+FS/PDWI; closed and open oblique coronal position: the long axis of the scan line parallel to the inner and outer diameter of the condyle, T1WI+FS, T2WI+FS/PDWI; enhancement: assessment of synovial inflammation
MR anatomy and normal presentation
TEMPOROMAND JOINT MR DISSECTION
The ontology of the joint disc consists of dense connective tissue (collagen fibers) and, as such, appears low-signal on T1WI, T2WI, and PDWI in the form of a double-concave black band shadow (often described as dumbbell or bow tie). The joint discs are clearly edged and clearly demarcated from the surrounding tissues. The bilabulum or post-market tissue is loose connective tissue and appears as hyperintensible. A clear boundary is visible between the joint retro-disc band and the double plate area, which becomes the post-disc boundary. In the closed position, the median disc center of the joint is located between the posterior slope of the joint nodule and the anterior slope of the condyle, and the retro-disc boundary should be near the apex of the condyle; in the opening position, the dumbbell-like shape of the joint disc is more pronounced, and the middle of the joint disc is "squeezed" between the apex of the condyle and the joint nodule
In the closed position, the median disc center of the joint is located between the posterior slope of the joint nodule and the anterior slope of the condyle, and the retro-disc boundary should be near the apex of the condyle; in the opening position, the dumbbell-like shape of the joint disc is more pronounced, and the middle of the joint disc is "squeezed" between the apex of the condyle and the joint nodule
Temporomandibular joint disorders characterized clinically by temporomandibular disc displacement are common. Temporomandibular disc displacement refers to the change in the position of the articular disc, the loss of the normal articular disc-condyle relationship when the mouth is closed, the displacement of the joint disc to the anterior (anterior and lower) of the condyle or the displacement to the inner and outer sides of the condyle, interfering with the movement of the mandibular, causing a series of clinical symptoms and signs, such as joint bounce, pain and limited opening. Joint disc displacement includes: simple anterior displacement, lateral part anterior displacement, medial partial anterior displacement, anterolateral rotation transfer position, anterior internal rotation transfer position, lateral displacement, medial displacement, posterior displacement, and articular disc morphology is not clear and cannot be classified. Clinical temporomandibular anterior disc displacement is the most common, usually divided into reversible anterior disc displacement and non-reversible anterior disc displacement, and this consensus focuses on the diagnostic criteria for anterior disc displacement of the joint.
Diagnosis of MRI
MRI diagnosis of articular disc displacement: the most common articular disc displacement is anterior or downward displacement, which can be divided into reversible anterior disc displacement and non-reversible anterior displacement according to whether the joint disc-condyle relationship can be restored at the time of opening. Mri for quantitative evaluation of anterior disc displacement is at disc dividing angles greater than 15 degrees, and anteriorly displaced articular disc is usually accompanied by varying degrees of deformation or swelling.
Disc dividing line: the dividing line (red line) between the posterior band of the joint disc and the double plate area when the mouth is closed; the dividing angle between the disc dividing line and the twelve-point direction of the condyle at the closed position
Normal opening: the condyle moves forward below the joint nodule, and the corresponding joint disc moves forward between the joint nodule and the condyle
According to the position of the articular disc after the temporomandibular joint movement, it is divided into reversible and non-reversible anterior displacement of the articular disc
Detailed interpretation of pathology
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The right and left temporomandibular joint discs in the closed position are both greater than 15 degrees, the right joint disc is swollen with effusion in the joint cavity, and the left and right joint discs in the open mouth are not reduced, and the diagnosis is bilateral temporomandibular joint disorder combined with the history
Source: Image Time
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