The Muscular System Movements Chapter 6.2

Flexion Decreases the angle of a joint Bring two bones closer together You will need to know the action or movement performed for each of the muscles we study. The first type of movement is called flexion. Note the lower leg is being flexed in this diagram. During flexion the angle of joint is decreased. As the knee is flexed, the angle between the lower leg and the thigh is decreased. Flexion of the upper arm is also illustrated in this diagram. Here the angle between the arm and the frontal plane is decreased.

Extension Increases the angle and distance between two bones Extension is the opposite of flexion. In extension the angle of a joint is increased. Extension of the lower leg causes an increased angle between the lower leg and the thigh.  

Hyperextension extension is greater than 180° Flexion and extension also apply to the neck. When a joint is extended past the anatomical position the movement is called hyperextension.

Abduction, Adduction & Circumduction Abduction: moving a limb away from the midline Adduction: movement of a limb toward the midline Circumduction: proximal end of limb is stationary, distal end moves in a circle Abduction refers to moving away from the median plane of the body. Adduction is the opposite movement to abduction. It is moving toward the medial plane. Circumduction refers to inscribing a circle while moving a limb.

Rotation movement of bone around its longitudinal axis Rotation is turning a bone on its own axis. Moving the head back and forth to indicate “no” is an example of rotation. Note the difference between medial and lateral rotation. In lateral rotation the limb is rotated the lateral side of the body. Medial rotation rotates the limb toward the medial side of the body.

Inversion- turn sole of foot medially Eversion- turn sole of foot laterally

Pronation- turn palm to face down (distal end of radius crosses over ulna) Supination- turn palm to face up (radius and ulna are parallel)

Dorsiflexion: point toes up, bring closer to tibia Plantar flexion: straightens ankle joint, toes point downward