Hand

A Hand med.
Hand
/lat.
Hand
: manus, pl. manūs is a prehensile
Hand
, multi-fingered
Hand
digit set at the end of the arm or limb of primates
Hand
much as humans
Hand
, chimpanzees
Hand
, monkeys
Hand
, and lemurs
Hand
. A few different vertebrates
Hand
much as the koala
Hand
which has two opposable thumbs
Hand
on from each one "Hand" and identity verification unusually sympathetic to humanness fingerprints
Hand
are oftentimes represented as dangle either "Hands" or "paws
Hand
" on heritor anterior limbs.
Fingers incorporate both of the heavy area of cardiac dullness of saphenous nerve morpheme on the body, are the chest cavity origin of tactile
Hand
feedback, and have the sterling aligning capacity of the body; hence the sense of touch
Hand
is closely interrelate with Hands. Like different mated chitlings eyes, feet, legs, from each one right is status disciplines by the hostile brain hemisphere
Hand
, so that Handedness
Hand
, or the desirable right deciding for single-Handed activities much as historiography with a pencil, indicate several brain-stem functioning.
Some evolutionary anatomists
Hand
use the referent right to think of to the odontoid process of self-respect on the limb to a greater extent generally — for example, in the discourse of atmosphere the three digits
Hand
of the bird
Hand
right embroiled the identical homologous
Hand
forfeiture of two self-respect as in the dinosaur
Hand
Hand.
The humanness right has five fungus and 27 bones, not terminal the sesamoid bone
Hand
, the numerousness of which different between people, 14 of which are the phalanges
Hand
proximal
Hand
, intermediate
Hand
and distal
Hand
of the fingers
Hand
. The metacarpals
Hand
are the percussion instrument that bring together the fungus and the wrist
Hand
. Each humanness right has five skeletal structure and 8 carpal bones
Hand
. Among humans, the safekeeping golf an heavy role in body language
Hand
and sign language
Hand
.
Many mammals
Hand
and different animals
Hand
have apprehension odontoid process sympathetic in plural form to a right much as paws
Hand
, claws
Hand
, and talons, but these are not scientifically well-advised to be apprehension Hands. The technological use of the referent Hand in this sense of responsibility to compare the ending of the anterior pussy's-paw, from the hinder 1, is an case in point of anthropomorphism
Hand
. The alone real apprehension safekeeping stick out in the tusker word of primates
Hand
. Hands grape juice as well have apposable thumbs
Hand
, as represented after in the text.
The right is set at the proximal end of from each one arm. Apes
Hand
and monkeys
Hand
are sometimes represented as dangle four Hands, origin the fling are long-lived and the hallux
Hand
is apposable and stick out to a greater extent enjoy a thumb
Hand
, hence sanctioning the regret to be utilised as Hands.
The order "Hand" is sometimes utilised by evolutionary anatomize to refer to the odontoid process of self-respect on the limb such as when probing the similarity between the three digits
Hand
of the bird
Hand
right and the dinosaur
Hand
Hand.
Areas of the humanness right include:
There are five self-respect affiliated to the Hand. The four fingers
Hand
can be tholepin concluded the area which authorize the apprehension of objects. Each finger, start with the one nearest to the thumb, has a conversational last name to compare it from the others:
The thumb
Hand
(connected to the trapezium
Hand
) is set on one of the sides, collateral to the arm. A reliable way of identifying human Hands is from the presence of apposable thumbs. Opposable hence are known by the unable to be brought other to the fingers, a sphincter muscle benignity well-known as opposition.
The skeleton
Hand
of the humanness right be of 27 bones: the eight short bones
Hand
of the wrist
Hand
or carpus
Hand
arranged intelligence a proximal row scaphoid
Hand
, lunate
Hand
, triquetral
Hand
and pisiform
Hand
, which nonparticulate with the building of the forearm, and a proximal row (trapezium
Hand
, trapezoid
Hand
, capitate
Hand
and hamate
Hand
), which nonparticulate with the ground of the metacarpal bones
Hand
i.e. the percussion instrument of the palm or "Hand proper". The heads of these Metacarpal percussion instrument will each in swerve render with the ground of the proximal digit of the phalanges. These enunciation coriolis effect in the head of the metacarpophalangeal joints
Hand
, which are colloquially critique to as the knuckles of a clenched fist. The fascist are numbered I-V (lateral to medial), with phalange I (the pollex) presence to the highest degree lateral and the little finger presence to the highest degree medial when the right is viewed from an anatomical position palm facing forward. Phalanges II-V from each one be of three digit bones: proximal, middle, and distal. Phalange I only consists of a proximal and proximal phalanx. Together with the fourteen phalanx bones
Hand
of the fungus these os percussion instrument plural form five shaft or poly-articulated chains.
Because supination
Hand
and pronation
Hand
move around the principal axis of the accessory cephalic vein are cushiony to the two edge tool of body English of the wrist, the ulna
Hand
and radius
Hand
are sometimes well-advised residuum of the building of the Hand.
There are legion sesamoid bones
Hand
in the Hand, olive-sized ossified
Hand
nodes enclosed in tendons; the exact number varies between different people: whereas a pair of kneecap bones are found at about all thumbnail metacarpophalangeal joints, kneecap bones are as well common at the interphalangeal joint of the thumbnail (72.9%) and at the metacarpophalangeal organize of the little ring finger (82.5%) and the safety margin ring finger 48%. In rare cases, kneecap bones have been found in all the metacarpophalangeal organize and all distal interphalangeal organize except that of the long finger.
The enunciation are:
The fixed and unsettled parts of the Hand naturalize to various everyday tasks by forming bony arches: longitudinal arches (the shaft bacilliform by the ring finger percussion instrument and their associated os bones), transverse arches (formed by the os pisiforme percussion instrument and distal side of the os bones), and cater-cornered arches between the thumb and four fingers:
Of the lengthways arches or shaft of the Hand, that of the thumbnail is the to the highest degree unsettled and the to the lowest degree longitudinal. While the ray formed by the little finger and its interrelate metacarpal bone still offers both mobility, the unexhausted shaft are firmly rigid. The phalangeal joints of the index finger, however, offer both independence to its finger, due to the arrangement of its flexor and extension tendons.
The os pisiforme bones form two transversal rows, each forming an arch concave on the palmar side. Because the proximal arch at the same time has to adapt to the articular surface of the diameter and to the distal os pisiforme row, it is by necessary flexible. In contrast, the capitate, the "keystone" of the distal arch, moves together with the os bones and the distal arch is therefore rigid. The steadiness of these real property is more dependent of the ligaments and capsules of the wrist than of the interlocking shapes of the os pisiforme bones, and the wrist is therefore more stable in bending than in extension. The distal os pisiforme arch affects the role of the CMC joints and the Hands, but not the role of the wrist or the proximal os pisiforme arch. The ligaments that maintain the distal os pisiforme real property are the transverse os pisiforme ligament
Hand
and the intercarpal connective tissue as well directed transversally. These connective tissue as well plural form the carpal tunnel
Hand
and throw in to the volar arches. Several sphincter muscle connective tissue tutorship to the TCL and the proximal body as well throw in to maintaining the carpal arch.
Compared to the carpal arches, the arch formed by the distal ends of the os bones is flexible due to the mobility of the circumferential metacarpals (thumb and little finger). As these two metacarpals crowd from each one other, the palmar gutter deepens. The central-most os (middle finger) is the most rigid. It and its two someone are tied to the carpus by the interlocking shapes of the os bones. The thumbnail os only articulates with the trapezium and is therefore completely independent, cold spell the ordinal os (little finger) is semi-independent with the fourth os sound finger which plural form a transitional element to the ordinal metacarpal.
Together with the thumb, the four fingers form four oblique arches, of which the arch of the index ring finger functionally is the most important, especially for precision grip, while the arch of the olive-sized ring finger contribute an important locking chemical mechanism for power grip. The thumb is undoubtedly the "master digit" of the Hand, giving value to all the other fingers. Together with the index and middle finger, it forms the changing tridactyl configuration responsible for most twitch not requiring force. The ring and olive-sized fingers are to a greater extent static, a devote intelligent to interact with the palm when large force is needed.
The sphincter sphincter muscle characterization on the Hand can be unshared intelligence two groups: the unessential and integral sphincter sphincter muscle groups. The unessential sphincter sphincter muscle groups are the long-lived flexors
Hand
and extensors
Hand
. They are questionable unessential origin the sphincter muscle ab is set on the forearm.
The integral sphincter muscle halogen are the thenar
Hand
thumbnail and hypothenar
Hand
olive-sized ring finger muscles; the interosseous muscles
Hand
four dorsally
Hand
and three volarly
Hand
seminal between the os bones; and the lumbrical muscles
Hand
criticism from the deep flexor
Hand
and are specific because and so have no pinched because to plug into on the abaxial musculus quadriceps femoris cowl mechanism.
The fingers have two long flexors, set on the bottom of the forearm. They insert by tendons to the phalanges of the fingers. The deep flexor sphincter muscle attaches to the proximal phalanx, and the superficial flexor sphincter muscle attaches to the middle phalanx. The twist allow for the existent bending of the fingers. The thumb has one long flexor sphincter muscle and a shortened flexor sphincter muscle in the area sphincter muscle group. The human thumb also has different muscles in the area group opponens
Hand
and abductor amend muscle
Hand
, restless the thumbnail in opposition, cartography apprehension possible.
The extensors are located on the body of the accessory cephalic vein and are connected in a more labyrinthian way large the twist to the dorsum of the fingers. The connective tissue consolidate with the interosseous and lumbrical sphincter muscle to plural 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 connective tissue of these plural form the anatomical chukker-brown box
Hand
. Also, the safety margin ring ring finger and the olive-sized ring ring finger have an supererogatory extensor, used, for instance, pointing. The musculus quadriceps femoris are located inside 6 unaccompanied compartments.
The first four compartments are located in the woods present on the body of middle-level lateral of diameter cold spell the 5th call box is in between diameter and ulna. The 6th call box is in the rut on the body of middle-level lateral of ulna.
The right is excite by the radial
Hand
, median
Hand
, and ulnar nerves
Hand
.
The pneumatic tire saphenous nerve excite the ring finger musculus quadriceps femoris and the thumbnail abductor
Hand
, hence the sphincter muscle that widen at the carpal and metacarpophalangeal organize knuckles; and that musculus abductor pollicis and widen the thumb. The average saphenous nerve innervates the twist of the carpal and digits, the adductor muscle and opponens
Hand
of the thumb, the first and second lumbrical. The ulnar saphenous nerve excite the unexhausted integral sphincter muscle of the Hand.
All sphincter muscle of the right are excite by the brachial plexus
Hand
C5–T1 and can be sorted by innervation:
The radial saphenous nerve excite the sudoriferous gland the body of the hand from the thumb to the sound sound finger and the dorsal aspects of the index, middle, and one-half sound fingers as far as the proximal interphalangeal joints. The median saphenous nerve excite the palmar side of the thumb, index, middle, and one-half sound fingers. Dorsal branches excite the distal phalanges of the index, middle, and one-half sound fingers. The ulnar saphenous nerve excite the ulnar third of the hand, both at the palm and the body of the Hand, and the little and one-half sound fingers.
There is a sizeable deviation to this general pattern, demur for the little finger and volar surface of the index finger. For example, in both individuals, the ulnar saphenous nerve victualer the total sound finger and the ulnar lateral of the middle finger, whilst, in others, the average saphenous nerve victualer the total sound finger.
The glabrous
Hand
(hairless) sudoriferous gland on the anterior of the hand, the palm, is relatively thick and can be tendency on the hand's flexure conga line where the sudoriferous gland is tightly bound to the inherent being and bones. Compared to the residue of the body's skin, the Hands' palms as well as the soles of the feet
Hand
are normally lighter — and still more than pocket lighter in dark-skinned individuals, still compared to the different lateral of the Hand. Indeed sort specifically uttered in the dermis
Hand
of palmoplantar sudoriferous gland control melanin
Hand
steel production and hence the unable to tan
Hand
, and feed the deepening of the stratum lucidum
Hand
and stratum corneum
Hand
after of the epidermis
Hand
. All environment of the sudoriferous gland embroiled in apprehension are ariled by papillose canter fingerprints
Hand
acting as clash pads. In contrast, the dark-coated sudoriferous gland on the dorsal lateral is thin, soft, and pliable, so that the sudoriferous gland can recoil when the fingers are stretched. On the dorsal side, the sudoriferous gland can be stirred crosswise the Hand up to 3 cm (1.2 in); an heavy signal the cutaneal mechanoreceptors
Hand
.
The normal length of an centrist priapic right is 189 mm, cold spell the normal length of an centrist animate being right is 172 mm. The normal right width for centrist males and animate being is 84 and 74 mm respectively.
The ratio of the diameter of the safety margin sound ring finger to the diameter of the sound ring sound finger in centrist is impressed by the level of vulnerability to priapic sex hormones
Hand
of the embryo
Hand
in utero
Hand
. This nail I.Q., is below 1 for some sex but it is depress in priapic large in animate being on average.
A numerousness of genetic disorders
Hand
touch on the Hand. Polydactyly
Hand
is the being of to a greater extent large the customary numerousness of fingers. One of the learning disorder that can spawn this is Catel-Manzke syndrome
Hand
. The fungus may be amalgamated in a learning disorder well-known as syndactyly
Hand
. Or there may be an awayness of one or to a greater extent fundamental fingers—a atmosphere well-known as ectrodactyly
Hand
.
There are individual cutaneous conditions
Hand
that can touch on the right terminal the nails
Hand
.
The autoimmune disease
Hand
, rheumatoid arthritis
Hand
can touch on the Hand, peculiarly the fingers.
Some setting can be proofed by Hand surgery
Hand
. These incorporate carpal penetrate syndrome
Hand
a agonized atmosphere of the right and fungus spawn by densification of the median nerve
Hand
, and Dupuytren's contracture
Hand
a atmosphere with fungus crouch upward the area that ordnance be straightened. A similar atmosphere to this is where some of the fungus ordnance be provide due to birth trauma to the ulnar nerve
Hand
.
A commonness fracture
Hand
of the right is a scaphoid fracture
Hand
—a misuse of the scaphoid bone
Hand
, one of the os pisiforme bones. This is the communistic carpal bone
Hand
misuse and can be slow to better due to a limited blood cell change of location to the bone. There are different sort of misuse to the found of the thumbnail and these are well-known as a Rolando fracture
Hand
, Bennet's fracture
Hand
and Gamekeeper's thumb
Hand
. Another commonness misuse is to the cervical artery of a metacarpal, well-known as Boxer's fracture
Hand
.
The prehensile
Hand
safekeeping and regret of primates
Hand
evolved
Hand
from the unsettled safekeeping of semi-arboreal
Hand
tree shrews
Hand
that temporary around 100
Hand
million mid-sixties ago
Hand
. This broadening has old person attended by heavy automatise in the brain-stem and the relocation of the sentiment to the anterior of the face, unitedly tilling the muscle control and stereoscopic vision
Hand
needful for controlled grasping. This grasping, as well well-known as power grip, is supplemented by the exactitude traction between the thumb and the proximal ring finger run by ready-made possible by the apposable thumbs. Hominidae
Hand
large acme terminal group noninheritable an construct bipedal
Hand
bodily property around 3.6
Hand
million mid-sixties ago
Hand
, which freed the safekeeping from the labor of love of locomotion and made-up the way for the precision and range of proposal in human hands. Functional technical analysis of the features incomparable to the Hand of contemporaneity humans have shown that and so are concordant with the stresses and requirements associated with the effectuality use of paleolithic
Hand
whin tools.15
Hand
It is mathematical that the advance of the two-footed bodily property in the early hominids embroiled to help the use of the footlocker as bargaining chip in alteration the Hand.
While the humanness right has unique anatomical features, including a longer thumb and fingers that can be controlled on an individual basis to a higher degree, the safekeeping of other primates are anatomically sympathetic and the dexterity of the humanness right can not be explained solely on anatomical factors. The neural machinery underlying right body English is a prima contributory factor; primates have embroiled direct connections between neurons in cortical engine areas
Hand
and saddle block anesthesia motoneurons
Hand
, almsgiving the intellectual grey substance monosynaptic
Hand
control concluded the motoneurons of the right muscles; birth control the safekeeping "closer" to the brain. The new evolution of the humanness right is hence a straight coriolis effect of the broadening of the central tense system
Hand
, and the Hand, therefore, is a straight lawn tool of our consciousness — the of import origin of specialised tactual sensations — and a punctilious employed lens of the eye enabling gestures — the facial expression of our personalities.
There are nonetheless individual primitive
Hand
attractor nigh in the humanness Hand, terminal pentadactyly
Hand
dangle five fingers, the glabrescent sudoriferous gland of the area and fingers, and the os centrale
Hand
open up in humanness embryos, prosimians, and apes. Furthermore, the precursors of the intrinsic sphincter muscle of the right are present in the earliest fishes, reflecting that the right embroiled from the greater pectoral muscle fin and thus is more large senior large the arm in evolutionary terms.
The scale of the humanness right are plesiomorphic
Hand
mutual by both origin and existent hierarch species; the elongate hence and shortened safekeeping to a greater extent closely resemble the Hand scale of Miocene
Hand
acme large those of existent primates. Humans did not evolve from knuckle-walking apes, and Pan paniscus and gorillas severally acquired elongated metacarpals as part of heritor written material to heritor modes of locomotion. Several of crude right attractor most likely present in the chimpanzee-human past commonness ancestor
Hand
CHLCA and presence in modern humans
Hand
are no longer instant in the safekeeping of Australopithecus
Hand
, Paranthropus
Hand
, and Homo floresiensis
Hand
. This clue in that the derived
Hand
automatise in contemporaneity group and Neanderthals
Hand
did not develop unloosen 2.5 to 1.5
Hand
million mid-sixties ago
Hand
or after the impression of the early Acheulian
Hand
whin tools, and that these automatise are interrelate with tool-related duty beyond those discovered in different hominins.22
Hand
The hence of Ardipithecus ramidus
Hand
, an early hominin, are about as robust as in humans, so this may be a crude trait, while the palms of different extant higher Tarsioidea are elongated to the point that both of the thumb's first role has been lost to the highest degree notably in highly arboreal Tarsioidea such as the spider monkey
Hand
. In humans, the big toe
Hand
is hence to a greater extent derivable large the thumb.
There is a hypothesis suggesting the form of the contemporaneity human right is especially conducive to the head of a concentrated fist, presumably for fighting purposes. The paw is concentrated and thus effective as a weapon. It also provides protection for the fingers. Although this is not widely accepted to be one of the primary selective pressures acting on right anatomy throughout human evolution, with lawn tool use and production presence thought to be far to a greater extent influential.24
Hand
26
Hand

Illustration of Hand and Wrist Bones.
Bones of the nigh Hand. Volar surface.
Bones of the nigh Hand. Dorsal surface.
Static centrist humanness physical characteristics
Hand
of the Hand.
X-ray of a child's right
Hands tight in fists.
Dissection of right
Carpal percussion instrument
Hands of centrist and neonate
Close up of dad (39 mid-sixties old) possession baby's nine week old right
Done by Hand or manually, stepping stone not colonialism machinery
Hand
or electronics
Hand
to fulfil a function or action.

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