Morphological Signs of Peripheral Nerves Structural Components Adaptation in the Middle Third of the Shoulder in Comparative Aspect

Abstract

A comparative microscopic study of the structural features of peripheral nerves of brachial plexus on the medial surface of the shoulder in the area of the middle third of the animals, being at the same stage of the evolutionary ladder, but in different existence conditions (a grey hare and European rabbit) was carried out. As a result, significant morphological differences in the structure of the peripheral nerves in studied parts of extremities have been revealed. Great physical activity performed by the forelimbs of animals in the natural conditions leads to a restructuring of the stromal and guiding components of the peripheral nerves that innervate the muscles of these limbs. Such microstructural changes are a manifestation of adaptive involution in vertebrates. Our findings are of fundamental character and they supply knowledge about the patterns of evolutionary processes of peripheral nervous system.