Temporomandibular disorder (TMD) is a disease of multifactorial etiology and a complex of symptoms, related to disorders of the masticatory muscles, temporomandibular joints and the surround-ing orofacial structures. One of the main problems in the course of TMD disorders is the systematic increase in the tension of the masticatory muscles (masseter muscles, temporalis and medial and lateral pterygoid muscles), what is the cause of many damages and the development of pathological conditions in the stomatognathic system.
The article discusses the differences in the structure of the masticatory and skeletal muscles, as well as the different nature and isoforms of myosin, which determines the much faster generation of contraction in the masticatory muscles and consequently easier generation of excessive, harmful tensions in the masti-catory muscles.
The article describes the causes of increased tension in the masticatory muscles and methods of their relaxation used in the basic and supportive treatment of temporomandibular disorders. The use of occlusal splints, physiotherapeutic procedures and TMD treatment with botulinum toxin type A were character-ized. A role of psychological support and the methods used for patients with TMD were emphasized.

TMD is a disease within the masticatory system that increases its reach among the society every year in the third and fourth decade of life. The etiology of TMD is complex and it is often difficult to establish the cause in a specific case. The aim of the study was to determine the impact of TMD on pathomorphological changes within the temporomandibular joints, evaluated in USG examinations and evaluation the assessment of differences in the number of pathological changes between various forms of TMD.
Material and Methods: The study material included a group of 386 patients, both sexes, aged 20 to 46 years, who came for prosthetic treatment due to symptoms of TMD. Ultrasound examination of the temporomandibular joints supplemented the clinical diagnosis of TMD in all the subjects. Axis I of the DC/TMD were used.
Results: Group I included 116 women and 89 men, group II consisted of 102 women and 79 men. Pathological morphological changes in the temporomandibular joints were found in all the examined patients. The changes in soft tissue structures were significantly increased in group II, but numerous pathomorphological changes were also present in the group of patients with the muscle form of TMD.
Conclusion: The results of the conducted studies with the use of USG temporomandibular joints revealed numerous pathomorphological changes within the temporomandibular joints. This indicates the usefulness of the USG examination in additional diagnostic tests in the group of patients with TMD.