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
Gross movements are big body movements relating to the use of the large muscles of the human body, such as those in the legs, arms, and abdomen, as opposed to fine movement of for example fingers or wrist.
According to the movements of joints
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.:212
According to the direction of the movement
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).
Movements of bones constitute what movements are normally possible in various joints of the human body. Animals may have different degrees of movement; due to different position of joints, different muscles and different structures that block motion in the human body.
Certain movements are difficult to classify, such as those of the carpal bones of the hand, or the tarsal bones of the foot, and are only really known by the orthopedic surgeon or hand surgeon specializing in their movements and not by ordinary medical practitioners.
Motions occurring over joints are also known as joint movements or osteokinematics, and depend on the joints of the body (mainly synovial. All motions that are created by the body are considered to be a mixture of or a single contribution of the following types of movement.
Most terms of a motion have clear opposites, and as such, are treated below in pairs.
Flexion and extension
Flexion describes a bending movement that decreases the angle between two parts. Bending the elbow, or clenching a hand into a fist, are examples of flexion. When sitting down, the knees are flexed. Flexion of the hip or shoulder moves the limb forward (towards the anterior side of the body).
Extension is the opposite of flexion, describing a straightening movement that increases the angle between body parts. In a conventional handshake, the fingers are fully extended. When standing up, the knees are extended. Extension of the hip or shoulder moves the limb backward (towards the posterior side of the body).
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 skiing, 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.  The inner thigh houses some adductors, including the adductor brevis, adductor longus, adductor magnus, and pectineus. The latissimus dorsi is a good example for the humerus.
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. The pectoralis major and subscapularis both medially rotate the humerus. The adductor longus and adductor brevis both medially rotate the thigh.
External rotation (or lateral rotation) refers to rotation away from the center of the body. for example, external rotation of the toes would turn the toes or the flexed forearm outwards (away from the midline). The sartorius laterally rotates the femur. The infraspinatus and teres minor both laterally rotate the humerus.
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]
- 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. "Windmilling" the arms or rotating the hand from the wrist are examples of circumductive movement.
- 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 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.:229
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.
Dorsiflexion is the movement which decreases the angle between the dorsum (superior surface) of the foot and the leg, so that the toes are brought closer to the shin.:123 and applies to the upward movement of the foot at the ankle joint. The muscles involved include those of the Anterior compartment of leg, specifically tibialis anterior muscle, extensor hallucis longus muscle, extensor digitorum longus muscle, and peroneus tertius. The range of motion for dorsiflexion indicated in the literature varies from 12.2 to 18 degrees. Foot drop is a condition, that occurs when dorsiflexion is difficult for an individual who is walking.
Plantarflexion (or plantar flexion) is the movement which increases the approximate 90 degree angle between the front part of the foot and the shin, as when depressing an automobile pedal or standing on the tiptoes. The word "plantar" is commonly understood in medical terminology as the bottom of the foot – it translates as "toward the sole". This movement is normally performed in either the supine, prone or standing position. Primary muscles for plantar flexion are situated in the Posterior compartment of leg, namely the superficial Gastrocnemius, Soleus and Plantaris (only weak participation), and the deep muscles Flexor hallucis longus, Flexor digitorum longus and Tibialis posterior. Muscles in the Lateral compartment of leg also weakly participate, namely the Fibularis longus and Fibularis brevis muscles. Those in the lateral compartment only have weak participation in plantar flexion though. The range of motion for plantar flexion is usually indicated in the literature as 30° to 40°, but sometimes also 50°. The nerves are primarily from the sacral spinal cord roots S1 and S2. Compression of S1 roots may result in weakness in plantarflexion; these nerves run from the lower back to the bottom of the foot.
Tibialis anterior muscle labeled at top center, and extensor muscles labeled at right
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. For example, prayer is often conducted with the hands dorsiflexed.
Palmarflexion is one of the movements of the wrist and hand which takes place at the wrist joint, where the angle between the palm and the forearm is decreased. In this context, this consists of bending the hand towards the inside of the wrist, an action known as flexion in anatomical terms.
Dorsiflexion refers to extension at the wrist joint. The opposite of this is dorsiflexion or extension; in the case of palmar extension, the angle between the back (dorsum) of hand and the forearm is reduced – specifically, the hand bends away from the inside of the wrist.
Pronation and supination
Pronation at the forearm is a rotational movement at the radioulnar joint, or of the foot at the subtalar and talocalcaneonavicular joints. For the forearm, when standing in the anatomical position, pronation will move the palm of the hand from an anterior-facing position to a posterior-facing position without an associated movement at the shoulder (glenohumeral joint). This corresponds to a counterclockwise twist for the right forearm and a clockwise twist for the left (when viewed superiorly). In the forearm, this action is performed by pronator quadratus and pronator teres muscle. Brachioradialis puts the forearm into a midpronated/supinated position from either full pronation or supination. For the foot, pronation will cause the sole of the foot to face more laterally than when standing in the anatomical position.
Pronation of the foot is a compound movement that combines abduction, eversion, and dorsiflexion. Regarding posture, a pronated foot is one in which the heel bone angles inward and the arch tends to collapse. Pronation is the motion of the inner and outer ball of the foot with the heel bone. One is said to be "knock-kneed" if one has overly pronated feet. It flattens the arch as the foot strikes the ground in order to absorb shock when the heel hits the ground, and to assist in balance during mid-stance. If habits develop, this action can lead to foot pain as well as knee pain, shin splints, achilles tendinitis, posterior tibial tendinitis, piriformis syndrome, and plantar fasciitis..
Supination of the forearm occurs when the forearm or palm face to the front (anteriorly) of the body. This action is performed by the biceps brachii and the supinator muscle. The arm is supine when in the anatomical position, and the supine position is also used when taking blood pressure. Supination of the foot occurs when the foot rolls outwards, placing most of the weight onto the outside of the foot and raising the arch. It is a compound movement that combines adduction, inversion, and plantar flexion.
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 is the movement of the sole of the foot away from the median plane. It occurs at the subtalar joint. The muscles involved in this include Fibularis longus and fibularis brevis, which are innervated by the superficial fibular nerve. Some sources also state that the fibularis tertius everts.:108
Inversion is the movement of the sole towards the median plane (as when an ankle is twisted). The muscles tibialis anterior and tibialis posterior invert. Some sources also state that the triceps surae and extensor hallucis longus invert.:123 Inversion occurs at the subtalar joint and transverse tarsal joint.
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 used to describe an eye movement that affects the vertical axis of the eye.
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 – To release an object by spreading the fingers and thumb.
Such terms include:
- Protraction and Retraction refer to an anterior (protraction) or posterior (retraction) movement of the arm at the shoulders. The major muscles involved in retraction include the rhomboid major muscle, rhomboid minor muscle and trapezius muscle, whereas the major muscles involved in protraction include the serratus anterior and pectoralis minor muscles.
- 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).:333 This word is derived from "to nod".(Latin: Nutare).
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