MANY ANATOMIC STRUCTURES and morphological relations are difficult to appreciate because they can be difficult or impossible to dissect. Furthermore, two-dimensional pictures may not replicate the anatomy in three dimensions or communicate how components relate spatially. Accordingly, anatomic models have long been used as educational tools because three-dimensional physical models can be more helpful than two-dimensional images in the learning and retention of anatomy content (1). As an

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... , Leonardo da Vinci used wax to cast the heart cavities of a bull in the early 16th century (3). In particular, the tracheobronchial tree has been characterized with models by numerous educators (2) as the airways are particularly difficult to visualize. Although models are often used by educators for teaching complex anatomy, the construction of models by students for learning complex anatomy is seldom reported (2). However, making anatomic casts or models by injecting solidifying substances into organs is an excellent way to provide an inquiry-based, collaborative, and problem-solving activity that enhances the learning of complex anatomy while promoting curiosity, skepticism, objectivity, and the use of scientific reasoning (2). Accordingly, four students (two rising second-year medical students, a rising senior undergraduate Exercise Science major, and a health science graduate student) worked together to make postmortem anatomic casts of the bronchial tree and pulmonary circulation of donated rat and pig carcasses. Specifically, in the rat, white and red Silastic sealants were injected into the trachea and pulmonary artery, respectively, which clearly differentiated the airways from the surrounding arterioles. In pig tissue, white sealant was injected into the trachea, whereas blue and red sealants were injected into the pulmonary artery and pulmonary veins, respectively. The pulmonary artery was accessed by making a cut at the apex of the heart and sending tubing through the right ventricle into the pulmonary artery. The pulmonary veins were filled by pushing tubing through the cut at the apex of the heart into the left ventricle, past the mitral valve and into the pulmonary veins. Since multiple vessels