Structure of snowy owls muscles of the chest wall and shoulder girdle with elements of their biomechanics

The aim of the study was to study the structural features of the muscles of the chest and shoulder girdle involved in the act of inhalation and exhalation in 1-year-old snowy owls. The studies were carried out at the Department of Animal Anatomy of the Faculty of Veterinary Medicine. We used the method of conventional dissection when studying the inspiratory and expiratory muscles of the chest wall and shoulder girdle. As a result of the study, we noted that the features of respiratory excursions of the chest wall were associated with its biomechanical properties. The respiratory muscles of birds were divided into the main (muscles of the chest wall) and auxiliary ones (muscles of the shoulder girdle). Additional respiratory muscles included inspiratory muscles (external intercostals, rib lifters, large and small sternocostals, diaphragm) and expiratory muscles (internal intercostals, sternocostals). Additional muscles in the shoulder girdle include the supeficial and deep serratus, the posterior scapular-shoulder muscle, the tensor aerodrum muscle, the pectoral muscle, and the supracoracoid muscle. Perhaps, a significant factor that reflects the morphofunctional connection of the constituent links during the contraction of the muscles and bones of the shoulder girdle is the muscles that form osteomuscular complexes, contributing to the close morphological connection of the organs of the locomotor apparatus with the organs of respiratory motility. The posterior part of the superficial layer of the serratus muscle had a highly developed belly, which was attached to the posterior edge of the scapula from the third to the sixth vertebral ribs in the area of attachment of the potent muscular fascicles of the diaphragm. The composition of the cranials included paired cervicals, anterior thoracics and interclaviculars (unpaired), and the posteriors included the posterior thoracic and abdominal (paired) air sacs. Сonsisting of mucous and serous membranes, they accomodated air worth 15-20% of the total volume of the body.