|aIn Rare Anatomy we meet the two boys whose vascular systems defy medical textbooks. Delve into the worlds of Osteogenesis Imperfecta (brittle bone syndrome) and Fibrodysplasia Ossificans Progressiva, a condition that progressively encases a person in a second skeleton. See how one man’s muscles fight against each other, while another’s have completely withered away. And discover what makes and breaks the intricate and delicate tissue we call skin, through the teenager whose skin grows thicker without flaking off, and a man with the opposite problem: his skin doesn’t stick to his body.