The skeleton is made up of 206 constant bones (200 bones and the 6 ossicles of the ear). However, apart from these there are other bones that can be inconstant, which are called accessories and sesamoids. Based on the above, the objective was to identify to the Os peroneum, which is one of the sesamoid bones that could be present in the human foot, relating its presence with sex, age groups and dominance, also recording measurements of each bone found. A descriptive study was carried out, in which radiographs of 200 patients of both sexes were used, Chilean, from the IX region of La Araucanía, 50 male and 150 female, aged between 15 and 90 years. Of the 200 patients studied, 28 (14 %) were found with the presence of peroneal bone, 23 of the female sex and 5 of the male sex. In 16 (57.1 %) individuals it was determined that the bones were bilateral. The biometric records of the bone under study are shown in tables. The data obtained will complement the morphological and medical knowledge about this bone in the Chilean population, since the pain in the lateral zone of the foot can be caused by a spectrum of etiologies, and with the data obtained, characterize our population, providing another possible cause to lateral standing pain.
KEY WORDS: Radiological anatomy; Foot; Sesamoid bones, Os peroneum.