STRUCTURE OF PARAPATELLAR CARTILAGES IN CANIDS

The aim of the study was to establish general patterns and morphological characteristics of the parapatellar structures of the knee joint in canids: dogs of factory breeding - Caucasian shepherd dog (n=15), Central Asian shepherd dog (n=14), poodle (n=9), the toy Terrier (n=13), Yorkshire Terrier (n=14) and Steppenwolf (n=17) and foxes (n=7) obtained from natural biocenoses. Subtle anatomical dissection was conducted and macroscopic evaluation of the structures was performed together with light microscopic analysis of serial histological sections stained with hematoxylin-eosin and picrofuchsin-fuchselin. Comparative analysis of the parapatellar cartilages allowed to establish both common regularities and breed-specific signs of their structure, that resulted from the impact of biomechanics of the locomotor behavior of the animals. In all the investigated canids parapatellar cartilages were formed by fibrous cartilaginous tissue with a predominance of fibrous structures over the cellular component and they could be divided into 3 zones - superficial, medial and deep. The peculiarities of the fibroarchitectonics of collagen bundles in each of them correspond to the nature of the pattern of biomechanical loads applied. Micromorphological studies performed show that parapatellar cartilages can act as compensatory devices, leveling functional overload of the quadriceps femoris in the extension phase of the knee joint.

knee, kneecap, parapatellar cartilage, the quadriceps muscle