Write paper on PREHENSION Research Example | Topics and Well Written Essays - 500 words

Write on PREHENSION - Research Paper Example movements of the several segments of fingers and hand we can hold, maintain, release, take the hand to objects or handle them and move them in all directions. Although the hand has multiple functions, the essential function is prehension. Such capacity appears from the tweezers lobster to the hand of the monkey, but in humans prehension reached its highest degree of functionality. This is due to a particular provision of thumb, which may object to all other fingers (Kapandji 1980).Human manipulative tasks are carried out by hand movements, that frequently involve forceful movements and prehension. The movement of the thumb causes the hand to be aligned with the forearm, resulting in a slight ulnar deviation of the wrist. The large number of muscles and joints of the hand obviously provides the equipment for numerous and varied patterns of movement. Not so evident, but equally important in determining complexity and dexterity of motion, are the large areas of the cerebral cortex given over to the coordination of motion and sensation in the hand. Thus, in the motor cortex the area devoted to the hands approximately equals the total area devoted to arms, trunk, and legs.  This circumstance ensures great potentiality for coordinated movement and for learning new activities. Similarly, the sensory areas are large, so that they determine such advanced functions as stereognosis, the ability to recognize the shape of an object simply by holding it in the hand. The great tactile sensitivity of the hand is, of course, in large part due to the rich supply of sense organs in the hand surface itself. The threshold for touch in the finger tip, for example, is 2 gm. per sq. mm. as compared to  33  and 26 for the forearm and abdomen respectively. Insertion of flexor and extensor muscle systems into several major segments along the proximal distal axis provides a variety of flexion extension patterns in the digits. With these attachments, fixation of carpal and metacarpal