Įxtension is the opposite of flexion, describing a straightening movement that increases the angle between body parts. Flexion of the shoulder or hip is movement of the arm or leg forward. When the chin is against the chest, the neck is flexed, and the trunk is flexed when a person leans forward. When a joint can move forward and backward, such as the neck and trunk, flexion is movement in the anterior direction. When a person is sitting down, the knees are flexed. For example, bending the elbow, or clenching a hand into a fist, are examples of flexion.
įlexion describes a bending movement that decreases the angle between a segment and its proximal segment. These terms come from the Latin words with the same meaning. A categoric list of movements and the muscles involved can be found at list of movements of the human body.įlexion and extension describe movements that affect the angle between two parts of the body. The study of movement in the human body is known as kinesiology.
Examples include a movement of the knee, where the lower leg changes angle compared to the femur, or movements of the ankle. The different parts of the object do not move the same distance.