Health

WHO says e-cigarettes 'undoubtedly harmful'

Electronic cigarettes are "undoubtedly harmful" and should be regulated, the WHO said Friday as it warned against the use of vaping products by smokers trying to quit their deadly habit.

Immunology

Home birth may start babies off with health-promoting microbes

For all of human history, babies have been born where their mothers lived—whether in a house, hut or cave. Only in the last century has birth moved out of the home and into the hospital. How has that changed the types of ...

Health

Exercises to head off a painful rotator cuff injury

(HealthDay)—The rotator cuff refers to a group of four distinct muscles and tendons that connect to each shoulder and stabilize the humerus, the upper arm bone. These muscles are engaged when you move your shoulder, and ...

Neuroscience

Surgery restores arm function in some paralysed patients: study

Surgeons in Australia have managed to restore arm function in paralysed patients, allowing them to feed themselves, use tools and handle electronic devices, according to the results of a groundbreaking study released Friday.

Neuroscience

Phantom sensations: when the sense of touch deceives

Without being aware of it, people sometimes wrongly perceive tactile sensations. A new study in the scientific journal Current Biology shows how healthy people can sometimes misattribute touch to the wrong side of their body, ...

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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