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General Terms of Motion

Note that body movements are always described in relation to the anatomical position of the body: upright stance, with arms to the side of body and palms facing forward.
Movement types are generally paired, one being the opposite of the other, as follows.

Flexion vs Extension

Flexion is a bending movement that decreases the angle between body parts. Hip or shoulder flexion is a forward movement of the leg or arm.
Extension is a straightening movement that increases the angle between body parts. Hip or shoulder extension is a backward movement of the leg or arm.

  • shoulder extension involves lifting the arm forwards, while shoulder flexion involves moving the arm backwards,
  • leg or knee extension consists in straightening the leg, while flexion refers to bending the leg at the knee,

Abduction vs Adduction

From the Latin preposition ab- “from, away from, of”.
Motion that pulls a structure or part away from the midline of the body. For example, raising the arms out to the sides, as in a tightrope walk, is shoulder abduction; or spreading the legs, as in a star jump or split, is hip abduction.
From the Latin preposition ad- “to, towards”.
Motion that pulls a structure or part towards the midline of the body. For example, lowering the arms alongside the body (shoulder adduction) or bringing the knees together (hip adduction).

Elevation vs Depression

Elevation refers to an upward movement. (e.g. shoulder shrug).
Depression refers to a downward movement.

External vs Internal Rotations

External rotation (lateral rotation or extorsion) is rotation away from the center of the body, carried out by external rotators.
Internal rotation (medial rotation or intorsion) is rotation towards the axis of the body, carried out by internal rotators.

Pronation vs Supination

Pronation (or pronated grip) = Rotation of the hand or forearm so that the palm is facing downward or toward the back and the thumb points towards the body. Opposed to *supination.
Supination (or supinated grip) = Rotation of the hand or forearm so that the palm is facing upward and the thumb points away from the body. Opposed to *pronation.

note: neutral position, neutral grip…