A 47-year-old man presented to the Emergency Department in November 2021 with right foot pain and difficulty walking. The patient had undergone trauma to the right ankle after a cut tree trunk snapped back and hit his posterior heel. He presented the next day after developing mild pain in the right lateral midfoot and pain with ambulation. He had full range of motion of the ankle and foot without difficulty. There were no open wounds. There was no tenderness to palpation over the Achilles tendon, and the patient was able to fully dorsiflex and plantarflex the foot. There was some mild tenderness to palpation in the proximal, dorsal midfoot with mild associated swelling. The patient had no prior history of injuries or pain in the ankle. Oblique and lateral right ankle X-rays were obtained and demonstrated the accessory bone (Figure 1), and the patient was diagnosed with an os trigonum.