Diseases, Conditions, Syndromes

Have a reusable face mask? Here's how to wash it the right way

Since the Centers for Disease Control and Prevention has recommended cloth face coverings for the general public, many have relied on those while reserving medical masks, such as N95 respirators, for medical workers.

Psychology & Psychiatry

Why writing by hand makes kids smarter

New brain research shows that writing by hand helps children learn more and remember better. At the same time, schools are becoming more and more digital, and a European survey shows that Norwegian children spend the most ...

Alzheimer's disease & dementia

Simple test can help detect Alzheimer's before dementia signs show

York University researchers say a simple test that combines thinking and movement can help to detect heightened risk for developing Alzheimer's disease in a person, even before there are any telltale behavioural signs of ...

Health

Do hand sanitizers really work? And if so, how?

Everywhere you turn of late, it seems you’re confronted with a bottle of alcohol-based hand sanitizer. We asked Professor James Scott whether these formulations work—and if so, how?

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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