ABSTRACT
Kinematics is the branch of mechanics that deals with pure motion without reference to the masses or forces involved. We define the chest wall as those parts of the body that surround the lung and that move with breathing. The chest wall consists of two parts, the rib cage and abdomen, the motion of which can be observed and measured. Chest wall kinematics has, therefore, primarily been concerned with measuring rib cage and abdominal motion. The tenn kinematics, however, also applies to the theory of mechanical mechanisms for converting one kind of motion to another. Since the chest wall may be considered a mechanical contrivance for converting one kind of motion (shortening of the respiratory muscles) to another (ventilation of the lungs), a complete understanding of the topic requires knowledge of how shortening of individual respiratory muscles is converted into rib cage and abdominal motion, and how this, in tum, influences the shape and volume of the lungs.
