FLEXORS OF THE ELBOW JOINT IN SOME REPRESENTATIVES OF THE CARNIVOROUS ORDER (CARNIVORA)

Abstract

Representatives of the predatory order have a similar anatomy of elbow flexors. However, due to the difference in lifestyles of individual predatory species, the abovementioned muscles are involved in the movement of the elbow joint in different ways. Using the basic principles of biomechanics allowed us to study the effect of each muscle at a certain point in the angle of the elbow joint. The material for the study was the corpses of a raccoon, raccoon dog and Mestizo dogs (weight 7-10 kg), delivered to the Department of Animal Anatomy from veterinary clinics in St. Petersburg and hunting farms in the Leningrad region. The research method was fine anatomical dissection. The moment of force is a physical quantity that is the product of the modulus of the force rotating the body by its shoulder and the sine of the angle between the shoulder and the modulus of force. Since sin(90º) =1, we built a perpendicular from the center of the axis to the force vector and this value was taken as the Moment Arm (MA). The fulcrum or center of the axis in this case is the center of the elbow joint. The force is represented as a vector, the direction of which is determined depending on the function of the muscle. The vector is based on the points of attachment of the muscle. Using the tpsDig2 program, we measured the Moment Arm of the muscles at different values of the angle of the elbow joint. The peak of the brachialis muscle in a raccoon stripper is at 72°, in a raccoon dog, the brachialis muscle is slightly involved in flexion of the elbow joint. The circular pronator in all individuals is weakly involved in flexion of the elbow joint. We have identified the biceps muscle of the shoulder and the shoulder muscle as the "main" flexors of the elbow joint, because at any value of the angle of the elbow joint, the muscles adhere to medium and high values. In dogs, the maximum range of motion of the elbow joint (MDD) is from 57° to 149°, in a raccoon from 45° to 158°, in a raccoon dog from 75° to 130°.