From a simple experiment, it can be demonstrated that the curved path of a medial impression follows behind the track rows by a “lag distance”;, indicating the length between the mid‐point of the tracks of the posterior‐most left and right legs and the medial impression. An animal's movement direction may therefore be deduced by this relationship. Fossil trackways of arthropods, reptiles, and dinosaurs show similar relationships between the path of the medial impression and track rows to results obtained experimentally. From the experimental results, it is also possible to determine the unexposed parts of the track rows and medial impression from the “lag distance”;