Twenty-seven patients with various types of internal TMJ disorders were examined at Voronezh Dental School Oral and Maxillofacial Surgery Department. All the patients underwent comprehensive examination and double-circuit TMJ arthroscopy, as well as joint fluid sampling for subsequent biochemical studies. A correlation between the degree of pathological changes of the TMJ intraarticular structures and biochemical parameters in traumatic TMJ lesions was discovered. The patterns observed may serve as a useful tool for more accurate diagnostics and treatment planning.