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Encyclopedia > Thumb
Thumb
The 'thumbs up' gesture is a sign of approval in many cultures, and an obscene gesture in many others.
Latin pollex, digitus primus, digitus I
Artery princeps pollicis artery
Lymph infraclavicular lymph nodes[1]
MeSH Thumb
Dorlands/Elsevier p_27/12655361

The thumb is one of the five fingers. Look up Thumb in Wiktionary, the free dictionary. ... Download high resolution version (864x1234, 335 KB) Wikipedia does not have an article with this exact name. ... A human hand with an upright thumb, literally a Thumb Up. A young man showing the thumbs up gesture. ... For gestures in computing, see mouse gesture. ... For other uses, see Latin (disambiguation). ... Section of an artery For other uses, see Artery (disambiguation). ... The princeps pollicis (principal artery of the thumb) arises from the radial artery just as it turns medially towards the deep part of the hand; it descends between the first dorsal interosseous muscle and the oblique head of the adductor pollicis, along the medial side of the first metacarpal bone... In mammals including humans, the lymphatic vessels (or lymphatics) are a network of thin tubes that branch, like blood vessels, into tissues throughout the body. ... One or two deltopectoral lymph nodes (or infraclavicular nodes) are found beside the cephalic vein, between the Pectoralis major and Deltoideus, immediately below the clavicle. ... Medical Subject Headings (MeSH) is a huge controlled vocabulary (or metadata system) for the purpose of indexing journal articles and books in the life sciences. ... Elseviers logo. ... This article does not cite any references or sources. ...

Contents

Anatomy of the thumb

Bones

The thumb consists of 3 bones:

In zootomy, several terms are used to describe the location of organs and other structures in the body of bilateral animals. ... The phalanges in a human hand Illustration of the phalalnges The name Phalanges is commonly given to the bones that form fingers and toes. ... In zootomy, several terms are used to describe the location of organs and other structures in the body of bilateral animals. ... The metacarpus is the intermediate part of the hand skeleton that is located between the fingers distally and the carpus which forms the connection to the forearm. ...

Muscles

Cross section - forearm
Cross section - forearm
Cross section - hand
Cross section - hand

Its movements are controlled by eight muscles (each with "pollicis" in the name): Image File history File links Gray417. ... Image File history File links Gray417. ... Image File history File links Gray422. ... Image File history File links Gray422. ...

Name Location Nerve
extensor pollicis longus forearm posterior interosseous nerve
abductor pollicis longus forearm posterior interosseous nerve
flexor pollicis longus forearm anterior interosseous nerve
extensor pollicis brevis forearm posterior interosseous nerve
abductor pollicis brevis hand median nerve
flexor pollicis brevis hand median nerve
opponens pollicis hand median nerve
adductor pollicis hand ulnar nerve (deep branch)

The extensor pollicis longus tendon and extensor pollicis brevis tendon form what is known as the anatomical snuff box (an indentation on the lateral aspect of the thumb at its base) The radial artery can be palpated anteriorly at the wrist(not in the snuffbox) In the hand, the abductor pollicis brevis, adductor pollicis, flexor pollicis brevis, and opponens pollicis form the thenar eminence. The Extensor pollicis longus muscle is a muscle of the human body. ... The deep branch of the radial nerve (dorsal or posterior interosseous nerve) winds to the back of the forearm around the lateral side of the radius between the two planes of fibers of the Supinator, and is prolonged downward between the superficial and deep layers of muscles, to the middle... The Abductor pollicis longus muscle is a muscle of the human body. ... The deep branch of the radial nerve (dorsal or posterior interosseous nerve) winds to the back of the forearm around the lateral side of the radius between the two planes of fibers of the Supinator, and is prolonged downward between the superficial and deep layers of muscles, to the middle... The Flexor pollicis longus muscle is a muscle of the human body. ... The anterior interosseous nerve (volar interosseous nerve) is a branch of the median nerve that supplies the deep muscles on the front of the forearm, except the ulnar half of the flexor digitorum profundus. ... The Extensor pollicis brevis muscle is a muscle of the human body. ... The deep branch of the radial nerve (dorsal or posterior interosseous nerve) winds to the back of the forearm around the lateral side of the radius between the two planes of fibers of the Supinator, and is prolonged downward between the superficial and deep layers of muscles, to the middle... The Abductor pollicis brevis muscle is a muscle of the human body. ... The median nerve is a nerve that runs down the arm and forearm. ... The Flexor pollicis brevis muscle is a muscle of the human body. ... The median nerve is a nerve that runs down the arm and forearm. ... The Opponens pollicis muscle is a muscle of the human body. ... The median nerve is a nerve that runs down the arm and forearm. ... The Adductor pollicis muscle is a muscle of the human body. ... In human anatomy, the ulnar nerve is a nerve which runs from the shoulder to the hand, at one part running near the ulna bone. ... The anatomical snuffbox, or radial fossa, (in Latin Foveola Radialis), is a triangular deepening on the radial, dorsal aspect of the hand - at the level of the carpal bones, specifically, the scaphoid and trapezium bones forming the floor. ... The thenar eminence is the body of muscle on the palm of the human hand just beneath the thumb. ...

Hitchhiker's thumbs
Hitchhiker's thumbs

Image File history File links Metadata No higher resolution available. ... Image File history File links Metadata No higher resolution available. ...

Hitchhiker's thumb

The thumb when extended (as in a "thumbs-up") can also appear to bend backwards toward the nail and outwards, a recessive congenital condition known as "hitchhiker's thumb", whereas for other people it will extend straight out with little backward bending. Having either condition appears to have no effect on the thumb's function. A human hand with an upright thumb, literally a Thumb Up. A young man showing the thumbs up gesture. ... It has been suggested that dominant allele be merged into this article or section. ... Mendelian inheritance (or Mendelian genetics or Mendelism) is a set of primary tenets relating to the transmission of hereditary characteristics from parent organisms to their children; it underlies much of genetics. ...


As one of five fingers, and as companion to four fingers

The English word "finger" has two senses, even in the context of appendages of a single typical human hand:

  1. Any of the five digits.
  2. The four digits, not including the thumb.

Linguistically, it appears that the original sense was the broader of these two: penkwe-ros (also rendered as penqrós) was, in the inferred Proto-Indo-European language, a suffixed form of penkwe (or penqe), which has given rise to many Indo-European-family words (tens of them defined in English dictionaries) that involve or flow from concepts of fiveness. Proto-Indo-European (PIE) may refer to: Proto-Indo-European language the hypothetical common ancestor of the Indo-European languages Proto-Indo-Europeans, the hypothetical speakers of the reconstructed Proto-Indo-European language Proto-Indo-European roots, A list of reconstructed Proto-Indo-European roots Categories: | ... For other uses, see Indo-European. ...


The thumb shares the following with each of the (other) four fingers:

  • Having a skeleton of phalanges, joined by hinge-like joints that provide flexion toward the palm of the hand
  • Having a "back" surface that features hair and a nail, and a hairless palm-of-the-hand side with fingerprint ridges instead

The thumb contrasts with each of the (other) four by being the only finger that: The phalanges in a human hand The name Phalanges is commonly given to the bones that form fingers and toes. ... A macro shot of a palm and the base of several fingers; as seen here, debris can gather between the ridges. ... This page is a candidate to be moved to Wiktionary. ...

  • Is opposable
  • Has two phalanges rather than three
  • Has its inmost phalanx so close to the wrist
  • Has much greater breadth and stubby proportions
  • Is attached to such a mobile metacarpus (which produces most of the opposability)

The metacarpus is the intermediate part of the hand skeleton that is located between the fingers distally and the carpus which forms the connection to the forearm. ...

Grips

Typical interdigital grips include the tips of thumb and second finger (forefinger/index finger) holding a pill or other small item, or thumb and sides of second and third fingers holding a pen or pencil. The index finger or forefinger is the second finger of a human hand, located between the thumb and the middle finger. ... The Index finger The index finger, pointer finger or forefinger is the second digit of a human hand, located between the thumb and the middle finger. ...


Origin of the thumb

The evolution of the opposable or prehensile thumb is usually associated with Homo habilis, the forerunner of Homo sapiens.[2][3][4] This, however, is the suggested result of evolution from Homo erectus (around 1 mya) via a series of intermediate anthropoid stages, and is therefore a much more complicated link. Prehensility is the quality of an organ that has adapted for grasping or holding. ... Binomial name Leakey et al, 1964 Homo habilis (pronounced ) (handy man, skillful person) is a species of the genus Homo, which lived from approximately 2. ... Homo sapiens (Latin: wise man) is the scientific name for the human species. ... Binomial name (Dubois, 1892) Synonyms † Pithecanthropus erectus † Sinanthropus pekinensis † Javanthropus soloensis † Meganthropus paleojavanicus Homo erectus (Latin: upright man) is an extinct species of the genus Homo. ... For other uses of mya, see mya (disambiguation). ... Families Cebidae Aotidae Pitheciidae Atelidae Cercopithecidae Hylobatidae Hominidae The simians (infraorder Simiiformes) are the higher primates very common to most people: the monkeys and the apes, including humans. ...


The most important factors leading to the habile hand (and its thumb) are:

  • the freeing of the hands from their walking requirements—still so crucial for apes today, as they have hands for feet, which in its turn was one of the consequences of the gradual pithecanthropoid and anthropoid adoption of the erect bipedal walking gait, and
  • the simultaneous development of a larger anthropoid brain in the later stages.

This article is about the biological superfamily. ... A biped is an animal that travels across surfaces supported by two legs. ... This article does not cite any references or sources. ... The human brain In animals, the brain (enkephalos) (Greek for in the skull), is the control center of the central nervous system, responsible for behavior. ...

Importance of the opposable thumb

The thumb, unlike other fingers, is opposable, in that it is the only digit on the human hand which is able to oppose or turn back against the other four fingers, and thus enables the hand to refine its grip to hold objects which it would be unable to do otherwise. The opposable thumb has helped the human species develop more accurate fine motor skills. It is also thought to have directly led to the development of tools, not just in humans or their evolutionary ancestors, but other primates as well [5][6]. The thumb, in conjunction with the other fingers make humans and other species with similar hands some of the most dexterous in the world[7]. Fine motor skills can be defined as small muscle movements which occur in the fingers, in coordination with the eyes. ...


Other animals with thumbs

Many animals, primates and others, also have some kind of opposable thumb or toe:

  • Bornean Orangutan - opposable thumbs on all four hands. The interdigital grip gives them the ability to pick fruit.
  • Gorillas-opposable on all four hands.
  • Chimpanzees have opposable thumbs on all four hands.
  • Lesser Apes have opposable thumbs on all four hands.
  • Old World Monkeys, with some exceptions, such as the genera, Piliocolobus and Colobus.
  • Cebids (New World primates of Central and South America) - some have opposable thumbs
  • Koala - opposable toe on each foot, plus two opposable digits on each hand
  • Opossum - opposable thumb on rear feet
  • Giant Panda - Panda paws have five clawed fingers plus an extra bone that works like an opposable thumb. This "thumb" is not really a finger (like the human thumb is), but an extra-long sesamoid bone that works like a thumb.
  • Troodon - a birdlike dinosaur with partially opposable thumbs.
  • Raccoon - a common mammal with thumbs, which are not opposables.

This article is about the primate. ... Type species Troglodytes gorilla Savage, 1847 distribution of Gorilla Species Gorilla gorilla Gorilla beringei The gorilla, the largest of the living primates, is a ground-dwelling omnivore that inhabits the forests of Africa. ... Type species Simia troglodytes Blumenbach, 1775 distribution of Species Pan troglodytes Pan paniscus Chimpanzee, often shortened to chimp, is the common name for the two extant species of apes in the genus Pan. ... Genera Hylobates Hoolock Nomascus Symphalangus Gibbons are the small apes that are grouped in the family Hylobatidae. ... Subfamilies Cercopithecinae - 11 genera Colobinae - 9 genera The Old World monkeys or Cercopithecidae are a group of primates, falling in the superfamily Cercopithecoidea in the clade Catarrhini. ... Type Species Simia (Cercopithecus) badius Kerr, 1792 Species Piliocolobus badius Piliocolobus pennantii Piliocolobus preussi Piliocolobus tholloni Piliocolobus foai Piliocolobus tephrosceles Piliocolobus gordonorum Piliocolobus kirkii Piliocolobus rufomitratus The red colobus are Old World monkeys of the genus Piliocolobus. ... Species Colobus satanas Colobus angolensis Colobus polykomos Colobus vellerosus Colobus guereza Black-and-white colobus are the Old World monkeys which bear a striking resemblance to skunks. ... Genera Callithrix Leontopithecus Saguinus Callimico Cebus Saimiri The Cebidae form one of the four familes of New World monkeys now recognised. ... For the drawing program, see KoalaPad/Painter. ... This article is about the body part. ... Genera Several; see text Opossum fur is quite soft. ... Panda Bear redirects here. ... In anatomy, a sesamoid bone is a bone embedded within a tendon. ... Binomial name Troodon formosus Leidy, 1856 Troodon formosus was a relatively small, bird-like dinosaur from the late Cretaceous Period (68–65 MYA). ... Binomial name (Linnaeus, 1758) Common Raccoon native range in red, feral range in blue. ...

See also

Look up Thumb in
Wiktionary, the free dictionary.

Wikipedia does not have an article with this exact name. ... Wiktionary (a portmanteau of wiki and dictionary) is a multilingual, Web-based project to create a free content dictionary, available in over 150 languages. ... Adducted thumb syndrome recessive form is a rare disease also known as Christian syndrome or Craniostenosis arthrogryposis cleft palate. ... A clubbed thumb is a term used to describe the genetic clubbing of one or both thumbs. ... Thumbing is the act of typing on a small keyboard solely (or primarily) using your thumbs. ... Thumb twiddling is an activity that is done with the hands of an individual whereby the fingers are interlocked and the thumbs circle around a common focal point, usually in the middle of the distance between the two thumbs. ... Thumb sucking is the act of putting your thumb in your mouth for a prolonged duration. ... When drawing a bow using an Asiatic grip, the thumb is hooked thumb around the string just beneath the arrow and braced with the first finger. ... The thumb is involved in thumb wrestling. ... Several inheritable traits or congenital conditions in humans are classical examples of Mendelian inheritance: Their presence is controlled by a single gene that can either be of the autosomal-dominant or -recessive type. ...

References

  1. ^ Norman/Georgetown clinicalconsiderations
  2. ^ http://www.reference-wordsmith.com/cgi-bin/lookup.cgi?category=&where=headword&terms=Homo
  3. ^ http://www.esalenctr.org/display/confpage.cfm?confid=10&pageid=103&pgtype=1
  4. ^ http://www.fortunecity.com/tatooine/acegarp/898/hominids.htm
  5. ^ http://www.nationalgeographic.com/xpeditions/lessons/01/g68/lonsdorf.html Lesson Plans - Chimps, Humans, Thumbs, and Tools]National Geographic, 2006, accessed April 26, 2007
  6. ^ Damonte, Kathleen Thumbs Are Handy DigitsNational Science Teachers Association: Science & Children: The Elementary Science Classroom. February 2004, accessed April 26, 2007
  7. ^ Chaisson, Eric J. Cosmic Evolution - Epoch 6 - Biological Evolution. Tufts University. 2007, accessed April 26, 2007

  Results from FactBites:
 
Thumb Osteoarthritis - Causes - Diagnosis - Symptoms - Treatment - Pain Relief (315 words)
Although there are several types of arthritis, the one that most often affects the joint at the base of the thumb (the basal joint) is osteoarthritis (degenerative or "wear-and-tear" arthritis), from AAOS.
Arthritis at the small joint at the base of the thumb is also referred to as CMC arthritis or basal joint arthritis.
Arthritis of the thumb is a form of osteoarthritis, also known as degenerative joint disease, from DynoMed.com.
Evolution: The Panda's Thumb [Athro, Limited: Biology] (970 words)
The "thumb" that underlies the thumb pad of the giant panda consists of a single bone that is not one of its normal digits.
In either case, the panda's thumb is a contrivance that is an artifact of the history of the panda.
The original function of the radial sesamoid was to reduce the chance of tears in the tendon that runs to the thumb from a muscle in the arm (the sesamoid forms where this tendon bends around the edge of the wrist).
  More results at FactBites »

 
 

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