Anatomical terms of motion
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Muscles drive all the movements in the human body, both voluntary and involuntary. They move organs, members, and the whole body in specific ways described by anatomical terminology. The terminology describes movement according to its direction. Anatomists use a unified set of terms to describe most of the movements, although other, more specialized terms are necessary for describing movements such as those of the hands, feet, and eyes.
The anatomical positions of the joints are the basis for description of most obvious skeletal movements, but there also are classes of movement, both voluntary and involuntary, in which joints and even skeletal elements play little part, such as movements of eyes, viscera and lips.
- 1 Classifications of motion
- 2 General motion
- 3 Special motion
- 3.1 Special motions of the hands and feet
- 3.2 Special motions of the eyes
- 3.3 Special motions of the jaw and teeth
- 3.4 Special motion of the fingers and thumb
- 3.5 Other
- 4 Notes
- 5 References
- 6 External links
Classifications of motion
Motions are classified after the anatomical planes they occur in, although movement is more often than not a combination of different motions occurring simultaneously in several planes. Additionally, motion may be divided into gross motion, affecting the large joints (such as legs, arms, and torso), and fine movements, which describe those made by the fingers, toes, feet or wrist. The study of movement is known as Kinesiology, and a categoric list of movements of the human body and the muscles involved can be found at List of movements of the human body.
Motions can be split into three categories as per how they engage different joints of the body:
- A gliding motion occurs between flat surfaces, such as in the intervertebral discs or between the carpal and metacarpal bones of the hand.
- An angular motion occurs over synovial joints and causes them to either increase or decrease angles between bones.
- A rotational motion moves a structure in a rotational motion in several planes.
Apart from this motions can also be divided into:
- Linear motions (or translatory motions), which move in a line between two points. A rectilinear motion refers to a motion in a straight line between two points, whereas a curvilinear motion refers to a 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 (plantar and dorsiflexion).
The prefix hyper- is sometimes added to describe movement beyond the normal limits to a limb's or organ's motion, such as in hyperflexion or hyperextension. Such movements are variously important; they may be used in surgery, such as in temporarily dislocating joints for surgical procedures, and also may be important in that they may seriously stress the joints involved. Such prefixes are common in Medical terminology. If a part of the body such as a joint is overstretched or "bent backwards" because of exaggerated extension motion, then one speaks of a hyperextension (as with the knee). This puts increased stress on the ligaments of the joint, and need not always be a voluntary movement, but may occur as part of accidents, falls, or other causes of trauma. Hyperextension is also sometimes defined as normal movement into the space posterior to the anatomical position.
These are general terms that can be use to describe most movements the body makes. Most terms have a clear opposite, and so are treated in pairs.
Flexion and extension
Flexion describes a bending movement that decreases the angle between two parts. For example, bending the elbow, or clenching a hand into a fist, are examples of flexion. When sitting down, the knees are flexed. Flexion of the shoulder or hip refers to movement of the arm of leg forward. 
Extension is the opposite of flexion, describing a straightening movement that increases the angle between body parts. When standing up, the knees are extended. Extension of the hip or shoulder moves the limb backward.  In a conventional hi-five, the fingers are fully extended.
Abduction and adduction
Abduction refers to a motion that pulls a structure or part away from the midline of the body (or, in the case of fingers and toes, spreading the digits apart, away from the centerline of the hand or foot). Abduction of the wrist is also called radial deviation.  Raising the arms laterally, such as when tightrope-walking, is an example of abduction at the shoulder. 
Adduction refers to a motion that pulls a structure or part toward the midline of the body, or towards the midline of a limb. Dropping the arms to the sides, or bringing the knees together, are examples of adduction. In the case of the fingers or toes, adduction is closing the digits together. Adduction of the wrist is also called ulnar deviation. Bringing the arms closer to the body is an example of adduction at the shoulder. 
Elevation and depression
The terms elevation and depression refer to movement above and below the horizontal. They derive from the Latin terms of the same meaning [c]
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 (or medial rotation) refers to rotation towards the axis of the body.  For example, a roman salute, in which the arm is placed against the chest, is an example of internal rotation.
- Anterograde and Retrograde flow, refers to movement of blood or other fluids in a normal (anterograde) or abnormal (retrograde) direction. 
- Circumduction refers to a conical movement of a body part, such as a ball-and-socket joint or the eye. 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 shoulder, but may also be performed by other parts of the body such as fingers, hands, feet, and head. A sporting example of circumduction occurs when performing a serve in tennis or bowling a cricket ball.
- Reduction refers to a motion returning a bone to its original state,  such as a shoulder reduction following shoulder dislocation, or reduction of a hernia.
The swinging action made during a tennis serve is an example of circumduction
Special motions of the hands and feet
Flexion and extension of the foot
Dorsiflexion and plantarflexion refers to extension (dorsiflexion) or flexion (plantarflexion) of the foot at the ankle. These terms refer to flexion between the foot and the body's dorsal surface, considered the front of the leg, and flexion between the foot and the body's plantar surface, considered the back of the leg.
Dorsiflexion where the toes are brought closer to the shin. This flexion decreases the angle between the dorsum of the foot and the leg.  An example includes the position of the foot when walking on the heels.
A ballerina, demonstrating plantarflexion of the feet.
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, considered the front of the arm, and flexion between the hand and the body's plantar surface, considered the back of the arm.
Pronation and supination
Pronation at the forearm is a rotational movement where the hand and upper arm are turned inwards. Pronation of the foot refers to turning of the foot outwards, so that weight is borne on the medial part of the foot. 
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.
Special motions of the eyes
Unique terminology is also used to describe the eye. For example:
- A Version is an eye movement involving both eyes moving synchronously and symmetrically in the same direction.,
- Torsion refers to eye movement that affects the vertical axis of the eye, such as the movement made when looking in to the nose.
Special motions of the jaw and teeth
- Occlusion refers to motion of the mandibula towards the maxilla making contact between the teeth.
- Protrusion and Retrusion are sometimes used to describe the anterior (protrusion) and posterior (retrusion) movement of the jaw. 
Special motion of the fingers and thumb
- Opposition refers to the movement that involves grasping of the thumb and fingers.
- Reposition refers to restoring an object to its natural condition , such as the releasing of an object by spreading the fingers and thumb.
Such terms include:
- Protraction and Retraction refer to an anterior (protraction) or posterior (retraction) movement,  such as of the arm at the shoulders.
- Reciprocal motion refers to alternating motions in opposing directions,  such as the elbow alternating between flexion and extension.
- Nutation and counternutation refer to movement of the sacrum defined by the rotation of the promontory downwards and anteriorly (nutation) or upwards and posteriorly (counternutation). This word is derived from "to nod".(Latin: Nutare).
- Marieb 2010, pp. 212.
- Lippert 2011, pp. 6-7.
- Seeley 1998, pp. 229.
- OED 1989, "Flexion, Extension".
- OED 1989, "Flexion".
- Cook 2012, pp. 180-193.
- OED 1989, "Extension".
- Swartz 2010, pp. 590–591.
- OED 1989, "Adduction, Abduction, Abduct".
- OED 1989.
- OED 1989, "elevation".
- OED 1989, "depression".
- Swartz 2010, pp. 590-1.
- OED 1989, "Anterograde, Retrograde".
- Saladin 2010, pp. 300.
- Taber 2001, "reduction".
- OED & 1989 "plantarflexion, dorsiflexion".
- Kyung 2005, pp. 123.
- Swartz 2010, pp. 591-3.
- Swartz 2010, pp. 591–592.
- OED 1989, "pronation".
- OED 1989, "supination".
- Swartz 2010, pp. 591.
- Kyung 2005, pp. 108.
- Kanski, JJ. Clinical Ophthalmology: A Systematic Approach. Boston:Butterworth-Heinemann;1989.
- Taber 2001, "Torsion".
- Taber 2001, "occlusion".
- Taber 2001, "protrusion, retrusion".
- Taber 2001, "opposition".
- OED 1989, "resposition".
- OED 1989, "protraction, retraction".
- Taber 2001, "reciprocation".
- Houglum 2012, pp. 333.
- OED 1989, "Nutation".
- The Oxford English dictionary. Oxford: Clarendon Press. 1989. ISBN 9780198611868.
- Willert, editor Donald Venes, Coeditor Clayton L. Thomas, Managing Editor Elizabeth J. Egan, Assistant Editors Nancee A. Morelli and Alison D. Nell. /copy Editor Ann Houska Proofreaders Joy Matkowski and Christopher Muldor. Dictionary Illustrator Beth Anne (2001). Taber's cyclopedic medical dictionary. (Ed. 19, illustrated in full color ed.). Philadelphia: F.A.Davis Co. ISBN 0-8036-0655-9.
- Swartz, Mark H. (2010). Textbook of physical diagnosis: history and examination (6th ed.). Saunders/Elsevier. ISBN 978-1-4160-6203-5.
- Cook, Chad E. (2012). Orthopedic manual therapy : an evidence based approach (2nd ed. ed.). Upper Saddle River, NJ: Pearson Education. ISBN 978-0-13-802173-3.
- Elaine N. Marieb, Particia Brady Wilhelm, Jon Mallat (2010). Human Anatomy. Pearson. ISBN 978-0-321-61611-1.
- Lippert, Lynn S. (2011). Clinical kinesiology and anatomy (5th ed.). F. A. Davis Company. ISBN 978-0-8036-2363-7.
- Seeley, Rod R.; Stephens, Trent D.; Tate, Philip (1998). Anatomy & Physiology (4th ed.). WCB/McGraw-Hill. ISBN 0-697-41107-9.
- Saladin, Kenneth S. (2010). Anatomy & Physiology The Unity of Form and Function (5th ed.). McGraw Hill.
- Kyung Won, PhD. Chung (2005). Gross Anatomy (Board Review). Lippincott Williams & Wilkins. ISBN 0-7817-5309-0.
- Houglum, Peggy A.; Bertoli, Dolores B. (2012). Brunnstrom's Clinical Kinesiology. F. A. Davis Company. ISBN 978-0-8036-2352-1.
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