<P> Flexion and extension describe movements that affect the angle between two parts of the body . These terms come from the Latin words with the same meaning . </P> <P> Flexion describes a bending movement that decreases the angle between a segment and its proximal segment . For example, bending the elbow, or clenching a hand into a fist, are examples of flexion . When sitting down, the knees are flexed . When a joint can move forward and backward, such as the neck and trunk, flexion refers to movement in the anterior direction . Flexion of the shoulder or hip refers to movement of the arm or leg forward . </P> <P> Extension is the opposite of flexion, describing a straightening movement that increases the angle between body parts . When a joint can move forward and backward, such as the neck and trunk, extension refers to movement in the posterior direction . For example, when standing up, the knees are extended . Extension of the hip or shoulder moves the arm or leg backward . When the chin is against the chest, the head is flexed, and the trunk is flexed when a person leans forward . </P> <P> Abduction is the motion of a structure away from the midline while adduction refer to motion towards the center of the body . The centre of the body is defined as the mid sagittal plane . These terms come from Latin words with similar meanings, ab - being the Latin prefix indicating "away," ad - indicating "toward," and ducere meaning "to draw or pull" (cf . English words "duct," "conduct," "induction"). </P>

What is the difference between flexion and extension