What is meant by the origin, insertion, and action of a muscle?

Answer 1

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The muscles origin is attached to the immovable bone. At its other end, the insertion is attached to the movable bone. Body movement occurs when muscles contract across joints and their insertion moves towards their origin.Angular movements increase or decrease the angle between two bones. Flexion decreases the angle of the joint and brings the articulating bones closer such as lowering the chin toward the chest. Extension is the reverse and increases the angle between bones such as straightening an elbow. Dorsiflexion is extension of the wrist and plantar flexion is extending the foot (pointing the toes). Abduction is movement of a limb away from the midline of the body. Aduction is bringing it toward the midline.

Answer 2

The point of origin and insertion are at the end of the muscles. When the muscle contracts (goes smaller) the insertion is pulled towards the origin (which is fixed) which creates movement.

Answer 3

muscles move your body. so if you bed your arm you are moving your forarm closer to your upper arm, using your bicep muscle. the origin of your bicep is where the tendon attaches your bicep to bone. the insertion is the other end of your bicep and where that attaches to bone. The best way to decipher which is the insertion and which is the origin is to think of it like this: WHen you flex that muscle the insertion moves toward the origin. so the origin of your bicep is near your shoulder and the insertion is on the top of your forearm.
the action is the is the action performed. flexion or extension or rotation (supination/pronation) for example.