Peroneus longus tendon rupture associated with an os peroneum
Complete rupture of the peroneus longus tendon just distal to an intrasubstance os peroneum. This case highlights how an understanding of the normal location of the os peroneum is essential to accurate plain film interpretation. The os peroneum should normally be located along side the cuboid. If it is displaced proximal to this, then a complete peroneus longus tear should be suspected.