Hand

A hand (med./lat.: manus, pl. manūs) is a prehensile, multi-fingered extremity located at the end of an arm or forelimb of primates such as humans, chimpanzees, monkeys, and lemurs. A few other vertebrates such as the koala (which has two opposable thumbs on each "hand" and fingerprints remarkably similar to human fingerprints) are often described as having either "hands" or "paws" on their front limbs.

Hands are the main structures for physically manipulating the environment, used for both gross motor skills (such as grasping a large object) and fine motor skills (such as picking up a small pebble). The fingertips contain some of the densest areas of nerve endings on the body, are the richest source of tactile feedback, and have the greatest positioning capability of the body; thus the sense of touch is intimately associated with hands. Like other paired organs (eyes, feet, legs), each hand is dominantly controlled by the opposing brain hemisphere, so that handedness, or the preferred hand choice for single-handed activities such as writing with a pencil, reflects individual brain functioning.

Some evolutionary anatomists use the term hand to refer to the appendage of digits on the forelimb more generally — for example, in the context of whether the three digits of the bird hand involved the same homologous loss of two digits as in the dinosaur hand.

The human hand has 27 bones, 14 of which are the phalanges (proximal, medial, and distal) of the fingers. The metacarpal is the bone that connects the fingers and the wrist. Each human hand has 5 metacarpals.

Read more about Hand:  Definitions, Evolution, Additional Images

Famous quotes containing the word hand:

    Bishop Berkeley destroyed this world in one volume octavo; and nothing remained, after his time, but mind; which experienced a similar fate from the hand of Hume in 1737.
    Sydney Smith (1771–1845)

    Whatsoever thy hand findeth to do, do it with thy might; for there is no work, nor device, nor knowledge, nor wisdom, in the grave, whither thou goest.
    Bible: Hebrew Ecclesiastes, 9:10.

    There are ... two minimum conditions necessary and sufficient for the existence of a legal system. On the one hand those rules of behavior which are valid according to the system’s ultimate criteria of validity must be generally obeyed, and on the other hand, its rules of recognition specifying the criteria of legal validity and its rules of change and adjudication must be effectively accepted as common public standards of official behavior by its officials.
    —H.L.A. (Herbert Lionel Adolphus)