This case study relates the story of “Hannah,” a 19-year-old runner struck by a deer during a cross country race. As a result of the collision, Hannah develops a pneumothorax that impairs her ability to breathe. Students follow her story as she is treated in the ER and readied for surgery. Students investigate how a pneumothorax disrupts the pressure gradients needed for pulmonary ventilation and causes the lung to collapse. They learn how a chest tube restores the pressure gradients, and consider the proper placement of a chest tube in light of thoracic anatomy. Finally, they address the differences between a simple pneumothorax and a tension pneumothorax, and why the latter can lead to a life-threatening drop in blood pressure. The case was written for a two-semester anatomy and physiology course taken by nursing, nutrition, athletic training, and other allied health majors in their first or second year. It could be adapted for use in a high school anatomy and physiology course, or an upper-level physiology or pathophysiology course.