Normal temporomandibular joint structure and function determined by ultrasound

Purpose. The purpose of this study was to determine ultrasound criteria of normal temporomandibular joint structure and function. Materials and methods. Prospective study was conducted upon normal 16 TMJs of 9 patients (4 male, 5 female with mean age of 22.9 years) without clinical or radiological signs of disc displacement. All the patients underwent high-resolution ultrasound (Samsung SONO ACE R3, 12 MHz linear probe) and MR imaging of TMJs with the mouth closed and during the maximal mandibular range of motion. Both examinations were performed and interpreted independently by blinded expert operators. Results. Mouth opening range varied from 4.4 cm to 5.4 cm, average amount was defined as 4.94 ± 0.39 cm. Also average heights of the front, middle and rear parts of disc were measured (0,42 ± 0,07 cm; 0,35 ± 0,07 cm and 0,41 ± 0,05 cm, respectively). Structure of the TMJ disc can be defined as fine-grained, hypoechoic and homogeneous. The average height of lower joint space was defined as 0,12 ± 0,03 cm. Average amount of maximal parasagittal mandible condyle movement was defined as 14.7 ± 1.38 mm. Conclusion. Obtained results of ultrasound criteria of normal temporomandibular joint structure and function correspond to the provisions of normal human anatomy and the norm values established for the MRI of the TMJ. Thus, ultrasound criteria of normal temporomandibular joint can be used for assessment of TMJ internal degenerative diseases. © 2018 Russian Electronic Journal of Radiology. All rights reserved.