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EncyclopediaHand > wrist-wraps
Hand
Human left hand
Latin manus
Vein dorsal venous network of hand
Nerve ulnar nerve, median nerve, radial nerve
MeSH Hand

The hands (med./lat.: manus, pl. manūs) are the two intricate, prehensile, multi-fingered body parts normally located at the end of each arm (medically: "terminating each anterior limb/appendage") of a human or other primate. They are the chief organs for physically manipulating the environment, using the roughest to the finest motor skills (wielding a club; threading a needle), and since the fingertips contain some of the densest areas of nerve endings on the human body, they are also the richest source of tactile feedback so that sense of touch is intimately associated with human hands. Like other paired organs (eyes, ears, legs), each hand is dominantly controlled by the opposing brain hemisphere, and thus handedness, or preferred hand choice for single-handed activities such as writing with a pen, reflects a significant individual trait. A hand is: Part of the human body, see hand A measurement of length, primarily used for the height of horses, see hand (unit). ... Image File history File links Download high-resolution version (533x850, 116 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Hand Wikipedia:Grays Anatomy images with missing articles 25 User talk:Mintguy/archive 4 List of images... Latin is an ancient Indo-European language originally spoken in Latium, the region immediately surrounding Rome. ... In the circulatory system, a vein is a blood vessel that carries blood toward the heart. ... The dorsal venous network of the hand is a network of veins formed by the dorsal metacarpal veins. ... Nerves (yellow) Nerves redirects here. ... 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 median nerve is a nerve that runs down the arm and forearm. ... The radial nerve is a nerve in the human body, that supplies the arm, the forearm and the hand. ... 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. ... Medicine is the science and art of maintaining andor restoring human health through the study, diagnosis, and treatment of patients. ... Latin is an ancient Indo-European language originally spoken in Latium, the region immediately surrounding Rome. ... This article does not cite any references or sources. ... Medicine is the science and art of maintaining andor restoring human health through the study, diagnosis, and treatment of patients. ... An appendage is, in general, an external body part that projects from the body, or a natural prolongation or projection from a part of any organism. ... This article is about modern humans. ... Families 15, See classification A primate is any member of the biological order Primates, the group that contains all the species commonly related to the lemurs, monkeys, and apes, with the latter category including humans. ... Tactition is the sense of pressure perception. ... The somatosensory system is the sensory system of somatic sensation. ... Handedness is an attribute of human beings defined by their unequal distribution of fine motor skill between the left and right hands. ...

Contents

What constitutes a hand?

Although many mammals and other animals have grasping appendages similar in form to a hand, (ie: paw, claw, talon, etc.), these are scientifically not considered to be so, and have other varying names. Using the term hand to distinguish the terminations of the front paws from the hind ones is merely a scientific usage of anthropomorphization. The only true hands appear in the mammalian order of primates. Hands must also have opposable thumbs, as described later in the text. Subclasses & Infraclasses Subclass †Allotheria* Subclass Prototheria Subclass Theria Infraclass †Trituberculata Infraclass Metatheria Infraclass Eutheria Mammals (class Mammalia) are warm-blooded, vertebrate animals characterized by the production of milk in female mammary glands and by the presence of: hair, three middle ear bones used in hearing, and a neocortex region in... For other uses, see Animal (disambiguation). ... A dogs paw resting on a hard concrete surface. ... Cat claw A claw is a curved pointed appendage, found at the end of a toe or finger or, in arthropods, of the tarsus. ... This article does not cite any references or sources. ... For the ecclesiastical use of this term, see primate (religion) Families 13, See classification A primate is any member of the biological order Primates, the group that contains all lemurs, monkeys, and apes, including humans. ... Missing image Thumbs up In human anatomy, the thumb is the first digit on a hand. ...


Humans have only two hands (except in cases of polymelia), which are attached to the arms. Some say that apes and monkeys have four hands, because the toes are long and the big toe is opposable and can somewhat be used as hands. // Polymelia (from Greek πολυ- = many plus μέλος (plural μέλεα) = limb) is a birth defect involving limbs (a type of dysmelia), in which the affected individual has more than the usual number of limbs. ... Ape is a member of the Hominoidea superfamily of primates. ... Approximate worldwide distribution of monkeys. ...


Anatomy of the human hand

The human hand consists of a broad palm (metacarpus) with five digits, attached to the forearm by a joint called the wrist (carpus).[1][2] The back of the hand is formally called the dorsum of the hand.


Digits

The four fingers

Four fingers on the hand are located at the outermost edge of the palm.[2] These four digits can be folded over the palm which allows the grasping of objects. Each finger, starting with the one closest to the thumb, has a colloquial name to distinguish it from the others: This article does not cite any references or sources. ...

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. ... Medicine is the science and art of maintaining andor restoring human health through the study, diagnosis, and treatment of patients. ... Latin is an ancient Indo-European language originally spoken in Latium, the region immediately surrounding Rome. ... This article is about the vulgar gesture. ... Medicine is the science and art of maintaining andor restoring human health through the study, diagnosis, and treatment of patients. ... Latin is an ancient Indo-European language originally spoken in Latium, the region immediately surrounding Rome. ... The ring finger on this hand is extended. ... Medicine is the science and art of maintaining andor restoring human health through the study, diagnosis, and treatment of patients. ... Latin is an ancient Indo-European language originally spoken in Latium, the region immediately surrounding Rome. ... The little finger, often called the pinky in American English and pinkie in Scottish English (from the Dutch word pink, meaning little finger), is the most ulnar and usually smallest finger of the human hand, opposite the thumb, next to the ring finger. ... Medicine is the science and art of maintaining andor restoring human health through the study, diagnosis, and treatment of patients. ... Latin is an ancient Indo-European language originally spoken in Latium, the region immediately surrounding Rome. ...

The thumb

The thumb (connected to the trapezium) is located on one of the sides, parallel to the arm. The thumb can be easily rotated 90º, on a perpendicular level compared to the palm, unlike the other fingers which can only be rotated approximately 45º. A reliable way of identifying true hands is from the presence of opposable thumbs. Opposable thumbs are identified by the ability to be brought opposite to the fingers, a muscle action known as opposition. The thumb is one of the five fingers. ... The trapezium is a bone in the human hand. ... Missing image Thumbs up In human anatomy, the thumb is the first digit on a hand. ... It has been suggested that Kinesiology#Motions be merged into this article or section. ...


Bones

An x-ray showing the bones of the human hand.
Illustration depicting the bones of the human hand

The human hand has 27 bones: the carpus or wrist account for 8; the metacarpus or palm contains 5; the remaining 14 are digital bones. Image File history File linksMetadata X-ray_boy_hand. ... Image File history File linksMetadata X-ray_boy_hand. ... In the NATO phonetic alphabet, X-ray represents the letter X. An X-ray picture (radiograph) taken by Röntgen An X-ray is a form of electromagnetic radiation with a wavelength approximately in the range of 5 pm to 10 nanometers (corresponding to frequencies in the range 30 PHz... Image File history File links Human_hand_bones_simple. ... Image File history File links Human_hand_bones_simple. ... In human anatomy, the carpal bones are the bones of the human wrist. ... 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. ...


Bones of the wrist

The wrist has eight bones, arranged in two rows of four. These bones fit into a shallow socket formed by the bones of the forearm. The bones of proximal row are (from lateral to medial): scaphoid, lunate, triquetral and pisiform. The scaphoid bone of the wrist is found on the thumb side of the hand, within the anatomical snuffbox. ... The lunate bone (os lunatum; semilunar bone) is a bone in the human hand that may be distinguished by its deep concavity and crescentic outline. ... The triquetral bone (also called triquetral, os triquetrum, cuneiform bone, pyramidal bone, cubital bone, os pyramidale, os triangulare, three-cornered bone, and triangular bone) is a type of carpal bone. ... The pisiform bone (also called pisiform or pisiforme os or lentiform bone) is a small knobbly, pea-shaped wrist bone. ...


The bones of the distal row are (from lateral to medial): trapezium, trapezoid, capitate and hamate. The trapezium is a bone in the human hand. ... In human anatomy, the trapezoid bone (lesser multangular bone; os multangulum minus) is a bone in the hands. ... The left capitate bone Os capitatum of the left hand, palmar surface Os capitatum of the left hand, dorsal surface The capitate bone (os capitatum; os magnum) is a bone in the human hand. ... The left hamate bone The hamate bone (os hamatum; unciform bone) is a bone in the human hand that may be readily distinguished by its wedge-shaped form, and the hook-like process which projects from its volar surface. ...


Bones of the palm

The palm has 5 bones (metacarpals), one to each of the 5 digits. These metacarpals have a head and a shaft. 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. ...


Digital bones

Main article: phalanx bones

Human hands contain 14 digital bones, also called phalanx bones: 2 in the thumb, and 3 in each of the four fingers. These are: The phalanges in a human hand Illustration of the phalalnges The name Phalanges is commonly given to the bones that form fingers and toes. ...

  • the distal phalanx, carrying the nail,
  • the middle phalanx and
  • the proximal phalanx.

(The thumb has no middle phalanx).


Sesamoid bones

Sesamoid bones are small ossified nodes embedded in the tendons to provide extra leverage and reduce pressure on the underlying tissue. Many exist around the palm at the bases of the digits, but the exact number varies between different people. In anatomy, a sesamoid bone is a bone embedded within a tendon. ... Ossification is the process of bone formation, in which connective tissues, such as cartilage are turned to bone or bone-like tissue. ...


Muscles and tendons

The movements of the human hand are accomplished by two sets of each of these tissues. They can be subdivided into two groups: the extrinsic and intrinsic muscle groups. The extrinsic muscle groups are the long flexors and extensors. They are called extrinsic because the muscle belly is located on the forearm.


Intrinsic hand muscles

The Intrinsic muscle groups are the thenar and hypothenar muscles (thenar referring to the thumb, hypothenar to the small finger), the interosseus muscles (between the metacarpal bones, four dorsally and three volarly) and the lumbrical muscles. These muscles arise from the deep flexor (and are special because they have no bony origin) and insert on the dorsal extensor hood mechanism. The thenar eminence is the body of muscle on the palm of the human hand just beneath the thumb. ... Hypothenar refers to a group of three muscles of the palm that control the motion of the little finger. ...


The extrinsic muscles of the hand

The flexors

The fingers have two long flexors, located on the underside of the forearm. They insert by tendons to the phalanges of the fingers. The deep flexor attaches to the distal phalanx, and the superficial flexor attaches to the middle phalanx. The flexors allow for the actual bending of the fingers. The thumb has one long flexor and a short flexor in the thenar muscle group. The human thumb also has other muscles in the thenar group (opponens- and abductor muscle), moving the thumb in opposition, making grasping possible. In anatomy and physiology, abduction is the moving of limbs away from the midline of the body. ...


The extensors

Located on the back of the forearm and are connected in a more complex way than the flexors to the dorsum of the fingers. The tendons unite with the interosseous and lumbrical muscles to form the extensorhood mechanism. The primary function of the extensors is to straighten out the digits. The thumb has two extensors in the forearm; the tendons of these form the anatomical snuff box. Also, the index finger and the little finger have an extra extensor, used for instance for pointing. The extensors are situated within 6 separate compartments. The 1st compartment contains abductor pollicis longus and extensor pollicis brevis. The 2nd compartment contains extensors carpi radialis longus and brevis. The 3rd compartment contains extensor pollicis longus. The extensor digitorum indicis and extensor digititorum communis are within the 4th compartment. Extensor digiti minimi is in the fifth, and extensor carpi ulnaris is in the 6th. The anatomical snuff box is a depression on the back of the hand, just beneath the thumb, that is formed by two tendons. ...


Variation

Some people have more than the usual number of fingers or toes, a condition called polydactyly. Others may have more than the typical number of metacarpal bones, a condition often caused by genetic disorders like Catel-Manzke syndrome. The average length of an adult male hand is 18.9cm, while the average length of an adult female hand is 17.2cm. The average hand breadth for adult males and females is 8.4cm and 7.4cm respectively. [2] This article is about the human congenital disorder (disease). ... Catel-Manzke syndrome is a rare genetic disorder characterized by distinctive abnormalities of the index fingers; the classic features of Pierre Robin syndrome; occasionally with additional physical findings. ...


Articulation

Also of note is that the articulation of the human hand is more complex and delicate than that of comparable organs in any other animals. Without this extra articulation, we would not be able to operate a wide variety of tools and devices. The hand can also form a fist, for example in combat, or as a gesture. Fist can refer to the following: A hand that has the fingers curled into the palm and the thumb retracted. ... This article includes a list of works cited or a list of external links, but its sources remain unclear because it lacks in-text citations. ...


See also

Dermatoglyphics (from ancient Greek derma = skin, glyph = carving) is the scientific study of fingerprints. ... The digit ratio is the ratio of the lengths of different digits, fingers or toes, typically as measured from the bottom crease where the finger joins the hand to the tip of the finger. ... It is proposed that this article be deleted, because of the following concern: Fringe fetish, I doubt there are any reliable sources about this out there. ... a handstand performed with straight legs A capoeirista performs a handstand with legs bent. ... Hand walking is an unusual form of locomotion, in which the walker moves primarily using their hands. ... In biology, dactyly is the arrangement of digits (fingers and toes) on the hands, feet, or sometimes wings of an animal. ... This is an example of a reflexology chart, correlating areas of the feet with organs in the zones of the body. ... Handedness is an attribute of human beings defined by their unequal distribution of fine motor skill between the left and right hands. ...

Gallery

References

  1. ^ [1] Nature Bulletin No. 611 October 1, 1960
  2. ^ a b "hand". Oxford English Dictionary. Oxford University Press. 2nd ed. 1989.

External links

Wikimedia Commons has media related to:
Hands
Look up Hand in
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  • Hand injuries and diseases (Handuniversity.com)
  • Hand anatomy (eMedicine)
  • Interesting facts about the hands

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