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Russian Journal of Theriology

Cinefluorographical study of the burrowing movements in the common mole, Talpa europaea (Lipotyphla, Talpidae) // Russian J. Theriol. Vol.1 (for 2002). No.2: 91109 [in English].

The burrowing process of the common mole Talpa europaea Linnaeus, 1758 was investigated by the cinefluorography. During burrowing the humerus is abduced only on 2530. This abduction is realized by the rotation of the scapula around its longitudinal axis and by the translation of the clavicle in the sternoclavicular and claviculohumeral joints. The abduction of the shoulder joint is limited to 1015 by nearly complete coincidence of the articular surfaces of the scapular glenoid fossa and the humeral head. The shoulder joint extension diminishes the abductors momentum on 3070% and in this case they cannot develop the force determined in the experiments. M. flexor digitorum profundus is transformed in the ligament which origins on the median epicondyle of humerus and inserts on all the five ungual phalanges. This is an unique mechanism for the neutralization pronation momentum of the humerus abductors. The increasing of the pressure of the hands on the soil augments the tension of the m. flexor digitorum profundus what hinders the pronation of the humerus. The increasing of the rotation of the antebrachium is necessary to maintain the hand in a parasagittal plane. An accretion of the humeral median epicondyle promotes decreasing of the humerus rotation. Humerus rotates during terrestrial locomotion in all tetrapods with sprawling limb position (humerus pronates in the propulsive phase and supinates in the swing phase). The recent Monotremata and probably primitive mammals use the humerus pronation for the lengthening of the stride. Mm. supraspinatus and infraspinatus prevent the humerus retraction. The widening of the humerus in these mammals is an adaptation to its rotation by the limited abduction and retraction. On the contrary, the widening of humerus in moles is an adaptation to its abduction by the limited rotation. Thus the convergent widening of the humerus in these animals is caused by the diametrically opposite functions. KEY WORDS: Talpa europaea, cinefluorography, biomechanical analysis, burrowing.