Numerous normal anatomic variants including different accessory ossicles and sesamoid bones are found around the foot and ankle region. They are usually of no clinical importance and are often recognized as an incidental radiographic finding. However, in the context of trauma, these ossicles may cause misdiagnosis due to various radiological pitfalls and this may result in under or overtreatment. Therefore, a thorough knowledge of these accessory ossicles and sesamoid bones is important for the physician to recognize the pathologic process and normal anatomic variants. This pictorial review summarizes the most common accessory ossicles found around the foot and ankle in skeletally mature subjects and the fractures that may cause confusion with accessory ossicles and sesamoid bones.
Keywords: Accessory ossicle, foot, ankle, fracture, os trigonum, os vesalianum, os intermetatarseum, os supranaviculare, os supratalare, os peroneum, os subtibiale, os subfibulare, hallux sesamoids, os calcaneus secundarius