Movements of a joint are called Actions. Understanding movement is the most important aspect of this course, in other words, if you know anything about a muscle, know what action(s) is does.
We will review the actions of each joint before covering muscles that move that joint, but here's an overview:
Don't get overwhelmed by all of the terms. We'll show you everything multiple times.
Each of the bullets is paired by action and counter action (opposite movement).
- Flexion - Bend or bring closer together. Extension - Straighten.
- Abduction - Move away from the midline (center of body). Adduction - Move closer to the midline.
- Circumduction - Combination of flexion, abduction, extension, adduction that only happens at the hip and shoulder joint; both ball and socket joints.
- Lateral Flexion - Bend side-to-side.
- Elevation - Move superiorly (up). Depression - Move inferiorly (down).
- Protraction (sometimes called Abduction) - Protrude forward. Retraction (sometimes called Abduction) - Retreat backward.
- External Rotation (also known as Lateral Rotation) - Rotation away from the midline. We use the term external rotation. Internal rotation (also known as Medial Rotation) - Rotation toward the midline. We use the term internal rotation.
- Rotation - Turn the neck or spine.
- Upward Rotation - Outside corner of the scapula moves up. Downward Rotation - Outside corner of the scapula moves down.
- Supination - External rotation of the radius to lie parallel with the ulna, turning the palms up. "Hold the soup or supinate is to the sun." Pronation - Internal rotation of the radius crossing over the ulna, turning the palms down. "Prone to spilling the soup or prone is to the plants."
- Radial Deviation - Abduction of the wrist. Ulnar Deviation - Adduction of the wrist.
- Plantar Flexion - Pointing your foot down like you're "wearing high heels or stepping on the gas pedal." Dorsiflexion - "Letting off the gas. The dorsal of a dolphin is on top."
- Inversion - Bottom of the foot toward the midline. "Look at the inside of the foot." Eversion - Bottom of the foot away the midline.
- Anterior/Posterior Tilt - Angle towards anterior (front) or posterior (back). Anterior tilt means "pour the bucket of water forward", posterior tilt means "pour the bucket of water backward."
- Lateral Tilt - One side of the pelvis elevates, one side lowers.
- Opposition - Thumb to a finger.
- Deviation - Moving the jaw side-to-side.
Do you remember the terms agonist, synergist, antagonist from the previous topic?