Two small bones in tendon of flexor hallucis brevis that articulate with plantar aspect of head of first metatarsal.
Blood supply to sesamoids comes from :
- proximal branch of first metatarsal artery
- plantar branch of first metatarsal artery
- via distal capsular attachment
Up to 20% of sesamoid bones are bipartite. Medial is bipartite 7x more than lateral.
Sesamoid is found in up to 40% under the hallux interphalangeal joint.
 Sobel M, Hashimoto J, Arnoczky SP et al: The microvascular of the sesamoid complex – its clinical significance. Foot & Ankle 13:359-363 1992