These little bones shaped like sesame seeds were described by Sommering in his treatise on posteology. Gillette (1874), Retterer (1884), Pfitzner (1890), Tedeschi (1891) (all cited by Testut 1904) and Inge and Ferguson (1933) all contributed to an understanding of their significance. Inge and Ferguson regarded the sesamoids as skeletal structures rather than true bones. They appear early, at about the 12th week of intra-uterine life, and appear to arise by ossification in cartilage. Later, they become surrounded by flexor hallucis brevis. Ossification is completed between the ages of 8 and 11 years.