As with all parts of the body, the anatomy and physiology of the chest wall are intimately intertwined. To carry out the unique functions performed by the chest wall, the anatomic structures are formed precisely for maximal efficiency. This article focuses on the unique structural characteristics in the internal thoracic diameters. It discusses the specific anatomy of the ribs and costal cartilages, along with the sternum. How these parts interrelate through joints is described also. Finally, it describes the muscles that cause the motion in the chest wall.