What is a Tarsal Coalition? Learn more about its symptoms and Causes   A tarsal coalition (also known as peroneal spastic flatfoot, calcaneonavicular bar, talocalcaneal bar, tarsal synostosis, or tarsal dysostosis) is an abnormal connection that develops between two bones in the back of the foot (the tarsal bones). This abnormal connection, which can be composed of bone, cartilage or fibrous tissue, […]