Sesamoid Evaluation Tip: Check First Ray ROM

     In the photo above, I am evaluating the motion and position (kinematics) of the first metatarsal (called first ray) crucial in sesamoid injuries. Of course, when there is significant pain and/or swelling in the big toe joint, this examination may not be accurate. With the patient lying on their stomach, or standing on the other leg with the examined side having the knee bent and the leg resting on a chair, you first stabilize the 2nd metatarsal head. Then, you grab the first metatarsal head with your thumbs parallel. Keeping the 2nd metatarsal still, you move the first metatarsal up and down (typical motion around 10 mm total or 1 cm). With sesamoid injuries, you are looking for reasons that the first metatarsal is overloaded. You may find either less than 10 mm of excursion (called hypomobile first ray), or all of the motion below the plane of the 2nd metatarsal (called plantar flexed first ray). Both these conditions can lead to the sesamoid pain in activities due to overload, and both these conditions can be treated. You treat hypomobility with physical therapy or massage therapy to increase overall first ray range of motion. You treat plantar flexed first rays with some form of dancer's padding to load the other metatarsals.