| Abstrakt: |
Prehension is a vital function according to its important role in serving the oral pole–for feeding–and the genital pole–for grooming and sexual activities. Everything is designed to give a maximum mobility to the terminal organ, the hand, which is in humans, unlike in monkeys, a multi-grasp unspecialised organ. Three different functional systems have to be described. The wrist/hand complex shows a very intelligent organisation of polyarticulated finger chains with an opposable thumb and all corresponding muscles allowing a great quantity of grasp and manipulation procedures. Then, the humero-radioulnar complex can regulate the length of the limb and put the hand in a supine or prone position thanks to the special trochoid radioulnar joint. Finally is the cleido-scapulohumeral complex that allows the upper limb to get 5 degrees of freedom (DF) for its spatial orientation resulting from only one junction to the axial skeleton: the sternoclavicular joint. Full responsibility lies then in the very powerful shoulder muscles for stabilising and moving the upper limb. [ABSTRACT FROM AUTHOR] |
