Melnyk O. Biomorphology of the musculoskeletal structures of shoulder girdle of birds irus

In the dissertation, with a help of osteological, osteometrical, radiographic and computed tomographic studies, data about structural features of skeletal and muscle components of shoulder joint of birds that belong to 91 species 22 orders of class of birds are given. Specific structural features as well as osteometrical characteristics of humerus, coracoid, scapula and furcula were established. It was found that relatively to the total length of the skeleton of wing the humerus is the longest in kiwi (66.3 %) that is a flightless bird and the shortest in black swifts (17.4 %) which is a high flight bird. This fact clearly shows that the longer humerus is the less fitness for flight a bird has. Humeral head has mostly flattened shape that substantially limits rotational movements of the shoulder joint and stabilizes the wings during flight. It was found that skeletal structures of the shoulder joint of Sphenisciformes, namely flattened humerus, caudally expanded scapula, mighty coracoid and furcula, were caused by the influence of increased functional loads that have arisen as a result of adaptation for performing rowing functions of wing during fast diving at great depths. It was established that the thickening of compact substance of both sides of skeletal structures of the shoulder joint are caused by different types of flight and relevant functional loads, which in turn necessitates strengthening of these structures. It was proved that the internal structure of skeletal structures of shoulder joint (thickness of compact substance, presence of different types of trabeculae branching) depends only on certain functional loads that influence on them that depends on the type of flight, its speed and duration. Computed tomographic studies showed that bony structures of the shoulder joint consists of bony rings that have myomere-like shape. These osteomers are divided into firm and soft that alternate each other. It was established that the amount of muscles that act on the shoulder joint of birds, their degree of development and differentiation are different due to the peculiarities of functioning of wing during flight, and in waterfowl due to features of diving with the use of wings.