STJ ROM
STJ ROM Dorsal view
The main function of the subtalar joint is to assist in transitioning the foot between being a rigid lever and a mobile adaptor during gait. The main movements that occur at the subtalar joint are inversion and eversion. To test these motions, your patient should be in a supine or seated position with their foot relaxed. Stabilise the leg above the ankle with one hand, and then, with the other hand, grasp the calcaneus from the posterior aspect. With your hands in this position, you may then move the subtalar joint through its full inversion and eversion range of motion. The expected range of motion is around 30 degrees total with twice as much inversion as eversion.