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:

    O thou immortal light and heat!
    Whose hand so shines through all this frame,
    That by the beauty of the seat,
    We plainly see who made the same.
    Seeing thy seed abides in me,
    Dwell thou in it, and I in thee.
    Henry Vaughan (1622–1695)

    One has observed life poorly, if one has not also witnessed the hand that mercifully—kills.
    Friedrich Nietzsche (1844–1900)

    Father Time is not always a hard parent, and, though he tarries for none of his children, often lays his hand lightly upon those who have used him well; making them old men and women inexorably enough, but leaving their hearts and spirits young and in full vigour. With such people the grey head is but the impression of the old fellow’s hand in giving them his blessing, and every wrinkle but a notch in the quiet calendar of a well- spent life.
    Charles Dickens (1812–1870)