From Applied Radiology Appl Radiol. 2007;36(10):28-37. Accessory Ossicles and Sesamoid Bones: Spectrum of Pathology and Imaging Evaluation Dr. Kalantari; Dr. Seeger; Dr. Chow; Dr. Motamedi Author Information Abstract (full text avaialble)
The authors describe a spectrum of accessory ossicle and sesamoid pathology and suggest appropriate imaging modalities. While they are considered to be normal anatomic variants, accessory ossicle and sesamoid bones may help to identify the source of patient symptomatology. The recognition of key imaging findings can help radiologists determine whether or not clinical symptoms are associated with these structures.

Pain related to the great toe sesamoids is uncommon in a general foot and ankle practice, but may be commoner where there is a large sports medicine component to the practice.
The hallux MTP sesamoids are embedded in the tendons of flexor hallucis brevis. They are subjected to the stresses of muscle contraction and MTP joint movement, and also to ground reaction force.