MORPHOFUNCTIONAL AND BIOELECTRIC CHARACTERISTICS OF SOME MUSCLES OF THE WRIST JOINT IN A DOG: PILOT STUDY

The paper presents the morphofunctional characteristics of some muscles of the dog's wrist joint, as well as their bioelectrical characteristics. The purpose of the study is to describe the bioelectrical characteristics of the radial and ulnar extensor carpi of the dog, taking into account the morphofunctional characteristics of these muscles. Objectives of the study: to conduct a morphological and electrophysiological study of the radial and ulnar extensor wrist muscles in dogs; identify patterns of EMG formation depending on the internal structure and innervation of muscles, and conduct a comparative assessment of the morphological and bioelectrical characteristics of the muscles being studied. Research was carried out at the Department of Anatomy, Histology, Physiology and Pathological Anatomy of the Omsk State Agrarian University named after P.A. Stolypin (Omsk). As a result of the studies, it was revealed that the innervation of the muscle fibers of the dog’s extensor carpi ulnaris and radialis has a similar, group character, that is, groups of muscle fibers have a large number of motor units. These groups are reflected on the EMG as separate complexes. An individual set of action potentials in the EMG signal pattern has duration of 0.01–0.014 s and a frequency of 600–800 Hz. The length of the muscle bundles inboth muscles is different: for the extensor carpi ulnaris it is 0.5 cm, for the radial one, respectively, 3.5 cm. Thus, it was found that the characteristics of the innervation and internal structure of the muscle affect the pattern of the EMG signal. The influence of muscle structure by the type of feathering and the length of muscle fibers (in feathery muscles) was not revealed. Thus, the resulting pattern (pattern) of the EMG signal is characteristic of statodynamic muscles. The proposed model of EMG signal formation, as a result of further development, will have the prospect of being used for qualitative and quantitative interpretation and assessment of the functional state of the neuromuscular system in animals and humans.