[Morphologico-functional study of the locomotor system of penguins as a principle of the general motor model of "underwater flight." II].

Based on the statements in part I according to the evolution of the underwater flight, its biophysical consequences and summarizing our knowledge on swimming performances of Penguins, the active and passive apparatus of movement was studied by dissection of 26 individuals of Pygoscelis papua, P. antarctica, P. adeliae, Eudyptes chrysolophus, and Aptenodytes forsteri. Besides the functional explanation of the Articulatio sternocoracoidea (diverging considerably from the usual type in birds), a new interpretation is given for the structures of the Articulatio humeri. In this context, the role of the Ligamentum acrocoracohumerale as an important element for co-ordination of the motion processes in the shoulder joint is elucidated. The essential curvature of the Caput humeri is found to be satisfactorily approximated by a logarithmic spiral. The understanding of the mechanics of bones and tendons leads to a reinterpretation of the role of several groups of muscles which is described in detail. Besides of the preponderant thrust producing (flapping) muscles working mainly in the isotonic manner, muscles can be distinguished which are managing the transfer of the produced forces to the body operating thereby in the isometric way. Another group of muscles has to control the position of the humerus adjusting in this way, the hydrodynamic angle of attack corresponding to the respective flow conditions.