Motion In physics, motion is the phenomenon in which an object changes its position with respect to time. Motion is mathematically described in terms of displacement, distance, velocity, acceleration, speed and frame of reference to an observer and mea ...

, the process of movement, is described using specific anatomical terms. Motion includes movement of organs,

joint A joint or articulation (or articular surface) is the connection made between bones, ossicles, or other hard structures in the body which link an animal's skeletal system into a functional whole.Saladin, Ken. Anatomy & Physiology. 7th ed. McGraw ...

s, limbs, and specific sections of the body. The terminology used describes this motion according to its direction relative to the

anatomical position The standard anatomical position, or standard anatomical model, is the scientifically agreed upon reference position for anatomical location terms. Standard anatomical positions are used to standardise the position of appendages of animals with ...

of the body parts involved. Anatomists and others use a unified set of terms to describe most of the movements, although other, more specialized terms are necessary for describing unique movements such as those of the hands, feet, and eyes. In general, motion is classified according to the

anatomical plane An anatomical plane is a hypothetical plane used to transect the body, in order to describe the location of structures or the direction of movements. In human and animal anatomy, three principal planes are used: * The sagittal plane or latera ...

it occurs in. ''Flexion'' and ''extension'' are examples of ''angular'' motions, in which two axes of a joint are brought closer together or moved further apart. ''Rotational'' motion may occur at other joints, for example the

shoulder The human shoulder is made up of three bones: the clavicle (collarbone), the scapula (shoulder blade), and the humerus (upper arm bone) as well as associated muscles, ligaments and tendons. The articulations between the bones of the shoulder m ...

, and are described as ''internal'' or ''external''. Other terms, such as ''elevation'' and ''depression'', describe movement above or below the horizontal plane. Many anatomical terms derive from

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power ...

terms with the same meaning.

Classification

Motions are classified after the

s they occur in, although movement is more often than not a combination of different motions occurring simultaneously in several planes. Motions can be split into categories relating to the nature of the joints involved: * ''Gliding'' motions occur between flat surfaces, such as in the

intervertebral disc An intervertebral disc (or intervertebral fibrocartilage) lies between adjacent vertebrae in the vertebral column. Each disc forms a fibrocartilaginous joint (a symphysis), to allow slight movement of the vertebrae, to act as a ligament to hol ...

s or between the

carpal bones The carpal bones are the eight small bones that make up the wrist (or carpus) that connects the hand to the forearm. The term "carpus" is derived from the Latin carpus and the Greek καρπός (karpós), meaning "wrist". In human anatomy, ...

of the

wrist In human anatomy, the wrist is variously defined as (1) the carpus or carpal bones, the complex of eight bones forming the proximal skeletal segment of the hand; "The wrist contains eight bones, roughly aligned in two rows, known as the carpal ...

, and the

metacarpal bones In human anatomy, the metacarpal bones or metacarpus form the intermediate part of the skeletal hand located between the phalanges of the fingers and the carpal bones of the wrist, which forms the connection to the forearm. The metacarpal bones ar ...

of the

hand A hand is a prehensile, multi-fingered appendage located at the end of the forearm 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 " ...

. * ''Angular'' motions occur over

synovial joint A synovial joint, also known as diarthrosis, joins bones or cartilage with a fibrous joint capsule that is continuous with the periosteum of the joined bones, constitutes the outer boundary of a synovial cavity, and surrounds the bones' articulat ...

s and causes them to either increase or decrease angles between bones. * ''Rotational'' motions move a structure in a

rotation Rotation, or spin, is the circular movement of an object around a '' central axis''. A two-dimensional rotating object has only one possible central axis and can rotate in either a clockwise or counterclockwise direction. A three-dimensional ...

al motion along a longitudinal axis, such as turning the head to look to either side. Apart from this motions can also be divided into: * ''Linear'' motions (or ''translatory'' motions), which move in a line between two points. ''Rectilinear'' motion is motion in a straight line between two points, whereas ''curvilinear'' motion is motion following a curved path. * ''Angular'' motions (or ''rotary'' motions) occur when an object is around another object increasing or decreasing the angle. The different parts of the object do not move the same distance. Examples include a movement of the knee, where the lower leg changes angle compared to the femur, or movements of the ankle. The study of movement in the human body is known as

kinesiology Kinesiology () is the scientific study of human body movement. Kinesiology addresses physiological, anatomical, biomechanical, pathological, neuropsychological principles and mechanisms of movement. Applications of kinesiology to human health ...

. A categoric list of movements and the

muscle Skeletal muscles (commonly referred to as muscles) are Organ (biology), organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other ...

s involved can be found at list of movements of the human body.

Abnormal motion

The prefix ''hyper-'' is sometimes added to describe movement beyond the normal limits, such as in '' hypermobility'', ''hyperflexion'' or ''hyperextension''. The

range of motion Range of motion (or ROM), is the linear or angular distance that a moving object may normally travel while properly attached to another. It is also called range of travel (or ROT), particularly when talking about mechanical devices and in mechanic ...

describes the total range of motion that a joint is able to do. For example, if a part of the body such as a joint is overstretched or "bent backwards" because of exaggerated extension motion, then it can be described as ''hyperextended''. Hyperextension increases the stress on the ligaments of a joint, and is not always because of a voluntary movement. It may be a result of accidents, falls, or other causes of trauma. It may also be used in surgery, such as in temporarily dislocating joints for surgical procedures. Or it may be used as a pain compliance method to force a person to take a certain action, such as allowing a police officer to take him into custody.

General motion

These are general terms that can be used to describe most movements the body makes. Most terms have a clear opposite, and so are treated in pairs.

Flexion and extension

Flexion and extension describe movements that affect the angle between two parts of the body. These terms come from the

words with the same meaning.), "to bend" ( la, flectere) Flexion describes a bending movement that ''decreases'' the angle between a segment and its proximal segment. For example, bending the

elbow The elbow is the region between the arm and the forearm that surrounds the elbow joint. The elbow includes prominent landmarks such as the olecranon, the cubital fossa (also called the chelidon, or the elbow pit), and the lateral and the m ...

, or clenching a hand into a fist, are examples of flexion. When a person is sitting down, the knees are flexed. When a joint can move forward and backward, such as the neck and trunk, flexion is movement in the anterior direction. When the chin is against the chest, the neck is flexed, and the trunk is flexed when a person leans forward. Flexion of the shoulder or hip is movement of the arm or leg forward. Extension is the opposite of flexion, describing a straightening movement that ''increases'' the angle between body parts. For example, when standing up, the knees are extended. When a joint can move forward and backward, such as the neck and trunk, extension is movement in the posterior direction. Extension of the hip or shoulder moves the arm or leg backward. Even for other upper extremity joints - elbow and wrist, movement behind results in extension. Except for knee, ankle, and wrist, where the distal end has to move in the anterior direction for it to be called extension. With regard to the toes, flexion means curling them downward whereas extension means uncurling them or raising them upward.

Abduction and adduction

Abduction is the motion of a structure away from the midline while adduction refers to motion towards the center of the body. The center of the body is defined as the midsagittal or

longitudinal Longitudinal is a geometric term of location which may refer to: * Longitude ** Line of longitude, also called a meridian * Longitudinal engine, an internal combustion engine in which the crankshaft is oriented along the long axis of the vehicle, ...

plane. These terms come from

words with similar meanings, ''ab-'' being the Latin prefix indicating "away," ''ad-'' indicating "toward," and ''ducere'' meaning "to draw or pull".), "to lead away" la, abducere Abduction is a motion that pulls a structure or part ''away from'' the midline of the body, carried out by one or more abductor muscles. In the case of fingers and toes, it is spreading the digits apart, away from the centerline of the hand or foot. For example, raising the arms up, such as when

tightrope Tightrope walking, also called funambulism, is the skill of walking along a thin wire or rope. It has a long tradition in various countries and is commonly associated with the circus. Other skills similar to tightrope walking include slack rope ...

-walking, is an example of abduction at the

. When the legs are splayed at the hip, such as when doing a

star jump __NOTOC__ A jumping jack, also known as a star jump and called a side-straddle hop in the US military, is a physical jumping exercise performed by jumping to a position with the legs spread wide and the hands going overhead, sometimes in a clap ...

or doing a

split Split(s) or The Split may refer to: Places * Split, Croatia, the largest coastal city in Croatia * Split Island, Canada, an island in the Hudson Bay * Split Island, Falkland Islands * Split Island, Fiji, better known as Hạfliua Arts, entertain ...

, the legs are abducted at the hip. Adduction is a motion that pulls a structure or part ''towards'' the midline of the body, or towards the midline of a limb, carried out by one or more adductor muscles. In the case of fingers and toes, it is bringing the digits together, towards the centerline of the hand or foot. Dropping the arms to the sides, and bringing the knees together, are examples of adduction. Adduction of the

is also known as ulnar deviation which moves the hand towards the ulnar styloid (or, towards the

little finger The little finger, or pinkie, also known as the baby finger, fifth digit, or pinky finger, is the most ulnar and smallest digit of the human hand, and next to the ring finger. Etymology The word "pinkie" is derived from the Dutch word ''pi ...

). Abduction of the wrist is also called radial deviation which moves the hand moving towards the

radial styloid The radial styloid process is a projection of bone on the lateral surface of the distal radius bone. Structure The radial styloid process is found on the lateral surface of the distal radius bone. It extends obliquely downward into a strong, c ...

(or, towards the

thumb The thumb is the first digit of the hand, next to the index finger. When a person is standing in the medical anatomical position (where the palm is facing to the front), the thumb is the outermost digit. The Medical Latin English noun for thu ...

).See
for appropriate image
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Elevation and depression

The terms elevation and depression refer to movement above and below the horizontal. They derive from the Latin terms with similar meanings), "to raise" ( la, elevare) Elevation is movement in a superior direction. For example, shrugging is an example of elevation of the scapula. Depression is movement in an inferior direction, the opposite of elevation.

Rotation

Rotation of body parts is referred to as internal or external, referring to rotation towards or away from the center of the body. Internal rotation (''medial rotation'' or ''intorsion'') is rotation towards the axis of the body, carried out by internal rotators. External rotation (''lateral rotation'' or ''extorsion'') is rotation away from the center of the body, carried out by external rotators. Internal and external rotators make up the

rotator cuff The rotator cuff is a group of muscles and their tendons that act to stabilize the human shoulder and allow for its extensive range of motion. Of the seven scapulohumeral muscles, four make up the rotator cuff. The four muscles are the supraspi ...

, a group of muscles that help to stabilize the

shoulder joint The shoulder joint (or glenohumeral joint from Greek ''glene'', eyeball, + -''oid'', 'form of', + Latin ''humerus'', shoulder) is structurally classified as a synovial ball-and-socket joint and functionally as a diarthrosis and multiaxial joint. ...

. File:Babaji.jpg, The

lotus position Lotus position or Padmasana ( sa, पद्मासन, translit=padmāsana) is a cross-legged sitting meditation pose from ancient India, in which each foot is placed on the opposite thigh. It is an ancient asana in yoga, predating hatha ...

yoga Yoga (; sa, योग, lit=yoke' or 'union ) is a group of physical, mental, and spiritual practices or disciplines which originated in ancient India and aim to control (yoke) and still the mind, recognizing a detached witness-conscio ...

, demonstrating ''external rotation'' of the thigh at the hip. File:Cable-internal-rotation-2.png, Rotating the arm away from the body is ''external rotation''. File:Cable-internal-rotation-1.png, Rotating the arm closer to the body is ''internal rotation''.

Other

* '' Anterograde'' and '' retrograde'' flow refer to movement of blood or other fluids in a normal (anterograde) or abnormal (retrograde) direction. * '' Circumduction'' is a conical movement of a body part, such as a

ball and socket joint The ball-and-socket joint (or spheroid joint) is a type of synovial joint in which the ball-shaped surface of one rounded bone fits into the cup-like depression of another bone. The distal bone is capable of motion around an indefinite number of ...

or the

eye Eyes are organs of the visual system. They provide living organisms with vision, the ability to receive and process visual detail, as well as enabling several photo response functions that are independent of vision. Eyes detect light and conv ...

. Circumduction is a combination of flexion, extension, adduction and abduction. Circumduction can be best performed at ball and socket joints, such as the hip and

, but may also be performed by other parts of the body such as fingers, hands, feet, and head. For example, circumduction occurs when spinning the arm when performing a serve in

tennis Tennis is a racket sport that is played either individually against a single opponent ( singles) or between two teams of two players each ( doubles). Each player uses a tennis racket that is strung with cord to strike a hollow rubber ball c ...

or bowling a cricket ball. * '' Reduction'' is a motion returning a bone to its original state, such as a shoulder reduction following shoulder dislocation, or reduction of a

hernia A hernia is the abnormal exit of tissue or an organ, such as the bowel, through the wall of the cavity in which it normally resides. Various types of hernias can occur, most commonly involving the abdomen, and specifically the groin. Groin hern ...

. File:Heather Watson Serve.jpg, The swinging action made during a tennis serve is an example of ''circumduction''

Special motion

Hands and feet

Flexion and extension of the foot

''Dorsiflexion'' and ''plantar flexion'' refer to extension or flexion of the foot at the ankle. These terms refer to flexion in direction of the "back" of the foot, which is the upper surface of the foot when standing, and flexion in direction of the sole of the foot. These terms are used to resolve confusion, as technically ''extension'' of the joint is dorsiflexion, which could be considered counter-intuitive as the motion reduces the angle between the foot and the leg.

Dorsiflexion Motion, the process of movement, is described using specific anatomical terms. Motion includes movement of organs, joints, limbs, and specific sections of the body. The terminology used describes this motion according to its direction relativ ...

is where the toes are brought closer to the shin. This decreases the angle between the dorsum of the foot and the leg. For example, when walking on the heels the ankle is described as being in dorsiflexion. Plantar flexion or plantarflexion is the movement which decreases the angle between the sole of the foot and the back of the leg; for example, the movement when depressing a car pedal or standing on tiptoes. File:017 'Ballerina' 18x24 oil on linen.jpg, A

ballerina A ballet dancer ( it, ballerina fem.; ''ballerino'' masc.) is a person who practices the art of classical ballet. Both females and males can practice ballet; however, dancers have a strict hierarchy and strict gender roles. They rely on ...

, demonstrating ''plantar flexion'' of the feet File:Dorsiplantar.jpg, Dorsi and plantar flexion of the foot

Flexion and extension of the hand

Palmarflexion and dorsiflexion refer to movement of the flexion (palmarflexion) or extension (dorsiflexion) of the hand at the wrist. These terms refer to flexion between the hand and the body's ''dorsal'' surface, which in

is considered the back of the arm; and flexion between the hand and the body's ''palmar'' surface, which in anatomical position is considered the anterior side of the arm. The direction of terms are opposite to those in the foot because of

embryo An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male sperm ...

logical rotation of the limbs in opposite directions. '' Palmarflexion'' is flexion of the wrist towards the

palm Palm most commonly refers to: * Palm of the hand, the central region of the front of the hand * Palm plants, of family Arecaceae ** List of Arecaceae genera * Several other plants known as "palm" Palm or Palms may also refer to: Music * Palm (b ...

and

ventral Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...

side of

forearm The forearm is the region of the upper limb between the elbow and the wrist. The term forearm is used in anatomy to distinguish it from the arm, a word which is most often used to describe the entire appendage of the upper limb, but which in ...

. ''

'' is

hyperextension Motion, the process of movement, is described using specific anatomical terms. Motion includes movement of organs, joints, limbs, and specific sections of the body. The terminology used describes this motion according to its direction relativ ...

of the

joint, towards the

dorsal Dorsal (from Latin ''dorsum'' ‘back’) may refer to: * Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism * Dorsal, positioned on top of an aircraft's fuselage * Dorsal co ...

side of forearm. File:Albrecht Dürer Betende Hände.jpg, '' Praying Hands'' by Albrecht Dürer, demonstrating ''dorsiflexion'' of the hands.

Pronation and supination

Pronation and supination refer generally to the prone (facing down) or

supine In grammar, a supine is a form of verbal noun used in some languages. The term is most often used for Latin, where it is one of the four principal parts of a verb. The word refers to a position of lying on one's back (as opposed to ' prone', ...

(facing up) positions. In the extremities, they refer to rotation of the forearm or foot so that in the

standard anatomical position The standard anatomical position, or standard anatomical model, is the scientifically agreed upon reference position for anatomical location terms. Standard anatomical positions are used to standardise the position of appendages of animals with ...

the palm or sole is facing anteriorly when in supination and posteriorly when in pronation. As an example, when a person is typing on a computer keyboard, their hands are pronated; when washing their face, they are supinated. ''

Pronation Motion, the process of movement, is described using specific anatomical terms. Motion includes movement of organs, joints, limbs, and specific sections of the body. The terminology used describes this motion according to its direction relativ ...

'' at the

is a rotational movement where the hand and upper arm are turned so the thumbs point towards the body. When the forearm and hand are supinated, the thumbs point away from the body. Pronation of the foot is turning of the sole outwards, so that weight is borne on the medial part of the foot. ''

Supination Motion, the process of movement, is described using specific anatomical terms. Motion includes movement of organs, joints, limbs, and specific sections of the body. The terminology used describes this motion according to its direction relativ ...

'' of the forearm occurs when the forearm or palm are rotated outwards. Supination of the foot is turning of the sole of the foot inwards, shifting weight to the lateral edge. File:Braus 1921 306.png, Supination and pronation of the foot File:Pronation and supination.jpg, Supination and pronation of the arm

Inversion and eversion

Inversion and eversion refer to movements that tilt the sole of the foot away from (eversion) or towards (inversion) the midline of the body. ''

Eversion Eversion (from the verb "evert") is the process of turning inside-out. Eversion may refer to: * Eversion (kinesiology), the anatomical term of motion denoting the movement of the sole of the foot away from the median plane * ''Eversion'' (video g ...

'' is the movement of the sole of the foot away from the

median plane The median plane also called a mid-sagittal plane is used to describe the sagittal plane as it bisects the body vertically through the midline marked by the navel, dividing the body exactly in left and right side. The term parasagittal plane is ...

. ''

Inversion Inversion or inversions may refer to: Arts * , a French gay magazine (1924/1925) * ''Inversion'' (artwork), a 2005 temporary sculpture in Houston, Texas * Inversion (music), a term with various meanings in music theory and musical set theory * ...

'' is the movement of the sole towards the

. For example, inversion describes the motion when an ankle is twisted. File:Eversion_and_inversion.jpg, Example showing inversion and eversion of the foot Éversion du pied.jpg, Eversion of the right foot File:Inversion du pied.jpg, Inversion of the right foot

Eyes

Unique terminology is also used to describe the eye. For example: * A '' version'' is an eye movement involving both

s moving synchronously and symmetrically in the same direction. * '' Torsion'' is eye movement that affects the vertical axis of the eye, such as the movement made when looking in to the nose.

Jaw and teeth

*'' Occlusion'' is motion of the

mandibula In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower teeth in place. The mandible sits beneath the maxilla. It is the only movable bone ...

towards the

maxilla The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The ...

making contact between the teeth. * ''

Protrusion Motion, the process of movement, is described using specific anatomical terms. Motion includes movement of organs, joints, limbs, and specific sections of the body. The terminology used describes this motion according to its direction relativ ...

'' and '' retrusion'' are sometimes used to describe the anterior (protrusion) and posterior (retrusion) movement of the jaw. File:Protrusion_and_retrusion.jpg, Examples showing protrusion and retrusion. File:Elevation_and_Depression.jpg, Elevation and depression of the jaw.

Other

Other terms include: * ''

Nutation Nutation () is a rocking, swaying, or nodding motion in the axis of rotation of a largely axially symmetric object, such as a gyroscope, planet, or bullet in flight, or as an intended behaviour of a mechanism. In an appropriate reference fra ...

'' and ''counternutation'') refer to movement of the

sacrum The sacrum (plural: ''sacra'' or ''sacrums''), in human anatomy, is a large, triangular bone at the base of the spine that forms by the fusing of the sacral vertebrae (S1S5) between ages 18 and 30. The sacrum situates at the upper, back part ...

defined by the rotation of the

promontory A promontory is a raised mass of land that projects into a lowland or a body of water (in which case it is a peninsula). Most promontories either are formed from a hard ridge of rock that has resisted the erosive forces that have removed the soft ...

downwards and anteriorly, as with lumbar extension (nutation); or upwards and posteriorly, as with lumbar flexion (counternutation). *'' Opposition'' is the movement that involves grasping of the thumb and fingers. *'' Protraction'' and ''

Retraction Retraction or retract(ed) may refer to: Academia * Retraction in academic publishing, withdrawals of previously published academic journal articles Mathematics * Retraction (category theory) * Retract (group theory) * Retraction (topology) Huma ...

'' refer to an anterior (protraction) or posterior (retraction) movement, such as of the arm at the shoulders, although these terms have been criticised as non-specific. *''

Reciprocal motion Reciprocating motion, also called reciprocation, is a repetitive up-and-down or back-and-forth linear motion (physics), motion. It is found in a wide range of mechanisms, including reciprocating engines and pumps. The two opposite motions that c ...

'' is alternating motions in opposing directions. *''Reposition'' is restoring an object to its natural condition. File:Braus 1921 231.png, Nutation at left, counternutation at right File:Ok sign.jpg, An example of ''opposition'' File:Opposition_CMX.jpg, Example of ''opposition'' of the thumb and index finger

Classification

Abnormal motion

General motion

Flexion and extension

Abduction and adduction

Elevation and depression

Rotation

Other

Special motion

Hands and feet

Flexion and extension of the foot

Flexion and extension of the hand

Pronation and supination

Inversion and eversion

Eyes

Jaw and teeth

Other

See also

Notes

References

Sources

External links