The only true grasping hands appear in the mammalian order of primates. The scientific use of the term hand in this sense to distinguish the terminations of the front paws from the hind ones is an example of anthropomorphism. Many mammals and other animals have grasping appendages similar in form to a hand such as paws, claws, and talons, but these are not scientifically considered to be grasping hands. Likewise, the ten digits of two hands and the twelve phalanges of four fingers (touchable by the thumb) have given rise to number systems and calculation techniques. Like other paired organs (eyes, feet, legs) each hand is dominantly controlled by the opposing brain hemisphere, so that handedness-the preferred hand choice for single-handed activities such as writing with a pencil, reflects individual brain functioning.Īmong humans, the hands play an important function in body language and sign language. They also have the greatest positioning capability of the body thus, the sense of touch is intimately associated with hands. Each human hand has five metacarpals and eight carpal bones.įingers contain some of the densest areas of nerve endings in the body, and are the richest source of tactile feedback. The metacarpal bones connect the fingers and the carpal bones of the wrist. It has 27 bones, not including the sesamoid bone, the number of which varies among people, 14 of which are the phalanges ( proximal, intermediate and distal) of the fingers and thumb. The human hand usually has five digits: four fingers plus one thumb these are often referred to collectively as five fingers, however, whereby the thumb is included as one of the fingers. 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 raccoon is usually described as having "hands" though opposable thumbs are lacking. A few other vertebrates such as the koala (which has two opposable thumbs on each "hand" and fingerprints extremely similar to human fingerprints) are often described as having "hands" instead of paws on their front limbs. A hand is a prehensile, multi- fingered appendage located at the end of the forearm or forelimb of primates such as humans, chimpanzees, monkeys, and lemurs.
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