Joint Action

Joint Action:

Joint actions are the labels given to the movement of bones around a joint. Each pair of joint actions is associated with a plane of motion.

Joint actions may be referred to as "osteokinematic motions" or "osteokinematic joint actions" to differentiate them from "arthrokinematic motions " (e.g., spin, glide, roll, compression, and distraction).

Joint Actions by Plane of Motion

Sagittal Plane Joint Actions

• Flexion: A decrease in joint angle (in the sagittal plane)
• Extension: An increase in joint angle (in the sagittal plane)

Frontal Plane Joint Actions

• Abduction: Movement away from the midline of the body (in the frontal plane).
• Adduction: Movement toward the midline of the body (in the frontal plane).
• Lateral Flexion: Displacement of the trunk away from the midline in the frontal plane (in the frontal plane).

Transverse Plane Joint Actions

• External (lateral) Rotation: Movement of the anterior side of a segment away from the midline of the body.
• Internal (medial) Rotation: Movement of the anterior side of a segment toward the mid-line of the body.
• Horizontal Adduction (flexion): Horizontal motion that results in movement toward the midline.
• Horizontal Abduction (extension): Horizontal motion that results in movement away from the midline.