The relationship between TMJ dysfunction and the anatomy of the lateral pterygoid muscle

Abstract

Possible causes of TMJ dysfunction are changes in the position of the condyle in the fossa, disc hypertrophy, inconsistencies between central occlusion (CO) and central ratio (CR) at the joint level, excessive articular effusion, altered bone morphology of the condyle, jaw injury, somatic diseases. Some studies indicate the effect of muscle attachment on the displacement of the articular disc, and also establish a correlation between pathological changes in the masticatory muscles themselves and disc displacement. The purpose of this study is to determine the role of attachment of the lateral pterygoid muscle and pathological changes in the masticatory muscle in the displacement of the articular disc. We have produced evaluation of MRI studies of 49 patients. The studies were performed on an Avanto superconducting MR tomograph with a field strength of 1.5 T. When comparing static images, the presence of motor artifacts was assessed, the volume of movements of the mandibular head was analyzed and the location of the articular disc at its various positions. The results of our study confirm that the lateral pterygoid muscle has different attachment patterns. The study revealed the presence of a third muscle head in 28% of cases. A statistically significant relationship has been established between the type of attachment of the lateral pterygoid muscle and the type of displacement of the articular disc.