Full Description
The hand commonly is considered to have exerted great influence on the evolution of typically human characteristics, like upright posture, stereoscopic vision, «manipulative» handling of parts of the environment. The German term «Begreifen», which is commonly used for the understanding of complex relationships in a generalised, abstract sense, always implies the original meaning of seizing objects with the aid of the hands. The hands are also of greatest importance for the survival of the other, non-human primates. Hands are absolutely essential for locomotion in an arboreal habitat, and the intake of food is dependant on the use of the hands as well: primates very rarely take in food directly with their mouths, in the wast majority of cases they seize food items with their hands. Even drinking is often performed by dipping the hand into the water and licking the drops from hand and forearm. An organ of such importance will very probably be «adapted» to its «function». This statement is made so often, that any further considerations seem superfluous. Nobody doubts, that the hands of primates are highly adaptive organs, the general form and internal structure of which are closely related to the necessities of life. However, if one tries to go beyond this general statement, he finds himself confront ed with several problems: First of all, a point which W. GUTMANN has emphasized repeatedly: according to the results obtained by genetics, the first thing to appear is the mutated character.
Contents
I. Hand Use.- Hand usage in the ring-tailed lemur (Lemur catta Linnaeus 1758) when solving manipulative tasks.- Locomotive and manipulative use of the hand in the Cayo Santiago macaques (Macaca mulatto).- Different hand postures for pounding nuts with natural hammers by wild chimpanzees.- Lateralised handedness, bipedalism and cortical specialisation.- The development of prehension in human and gorilla infants.- Grasping techniques and hand preferences in Hominoidea.- Energetic cost of nut-cracking behaviour in wild chimpanzees.- II. Hand Function.- Biometrical characteristics of primate hands.- New results concerning the vascularization of primate hands. Part I: The palmar arterial arches in Cercopithecidae, Pongidae, Hominidae and other primates.- New results concerning the vascularization of primate hands. Part II: The capillaries in the dermal ridges of fingers (and palms) in man and monkeys.- Adaptations in the hands of cercopithecoids and callitrichids.- Joints and muscles of hands and paws.- Muscle fibre and tendon lengths in primate extremities.- Biomechanical determinants of reduction of the second ray in Lorisinae.- Functional morphology of the human carpus.- Biomechanical considerations to explain important morphological characters of primate hands.- Elasticity of hand and forefoot tendons.- The relationship between the function and the inner cortical structure of metacarpal and phalangeal bones.- Investigations on the biomechanical significance of dermatoglyphic ridges.- III. Hand Development.- The constructional preconditions of the basic organization of the tetrapod limb.- Evolution and the hand.- A survey of fossil primate hands.- The oldest primate hands: Additional remarks and observations.- New hand bones of the early Miocene hominoid Proconsul and their implications for the evolution of the hominoid wrist.- On the development of the human hand.
