From the manufacturer:
In the second volume of Dr. Livingston’s Anatomy Jigsaw Puzzles, you will assemble a cross-cut section of the human body that gives you a clear view of the entire rib cage and its contents. You’ll see how they interlock and overlap with marvelous intricacy. As you assemble this puzzle you’ll frame the organs with crosscuts of the the sternum, ribs, and thoracic vertebrae. Inside that protective cage lie a wealth of vital and vulnerable organs; the trachea carries air to the two lungs, and sitting between them, the four-chambered heart pumps blood through the pulmonary circulatory loop of the lungs. From there, once the blood is rich with fresh oxygen, it begins its journey through the systemic circulatory system to carry that oxygen to the rest of the body.