Two chiral catalysts working hand in hand

Just as our left hand is not superposable to our right hand, the mirror image of certain molecules cannot be overlapped onto it, even when turned or twisted. These two mirror images are referred to by chemists as enantiomers ...

Gimme six! Researchers discover aye-aye's extra finger

The world's weirdest little primate has gotten even weirder, thanks to the discovery of a tiny extra digit. A study led by researchers from North Carolina State University has found that aye-ayes possess small "pseudothumbs"—complete ...

Molecular nanocarbons with mechanical bonds

Carbon materials with nano-scale periodicity such as graphene and carbon nanotubes, called "nanocarbons," are expected to become light, highly functional next-generation materials. There have been demands for precise synthesis ...

Northern France was already inhabited more than 650,000 years ago

The first evidence of human occupation in northern France has been put back by 150,000 years, thanks to the findings of a team of scientists from the CNRS and the Musée National d'Histoire Naturelle at the emblematic site ...

An astonishing parabola trick

Prospective digital data storage devices predominantly rely on novel fundamental magnetic phenomena. The better we understand these phenomena, the better and more energy efficient the memory chips and hard drives we can build. ...

Team programs a humanoid robot to communicate in sign language

For a robot to be able to "learn" sign language, it is necessary to combine different areas of engineering such as artificial intelligence, neural networks and artificial vision, as well as underactuated robotic hands. "One ...

page 1 from 23

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 chief organs 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 pen, 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 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.

This text uses material from Wikipedia, licensed under CC BY-SA