Hallux sesamoid

Dr Mostafa El-Feky and Dr Henry Knipe et al.

The hallux sesamoid bones are paired ossicles of the foot. They function as a fulcrum to increase the leverage of both flexor hallucis brevis and longus

The hallux sesamoids are ovoid-shaped ossicles, separated from each other by the intersesamoidal ridge. There is a medial (tibial) and lateral (fibular) hallux sesamoid, which are embedded within the substance of the medial and lateral slips of the tendon of the flexor hallucis brevis muscle respectively 1. They are usually 1.3 cm long x 0.3 cm wide 2. The medial sesamoid is generally larger than the lateral seasmoid and it also occupies a more distal and superficial (plantar) position.

During dorsiflexion of the hallux, the sesamoids lie below the first metatarsal head, offering protection to the otherwise exposed plantar aspect of the first metatarsal head.

Along with the tendons and ligaments listed below, the sesamoid bones form the hallux sesamoid complex.

  • cartilaginous dorsal surface articulates with the grooved undersurface of the first metatarsal head
  • intersesamoid ligament
    • connects the two hallux sesamoids strongly to form one functional unit 2
    • forms the floor of the tendinous canal for the tendon of flexor hallucis longus
  • medial and lateral collateral ligaments
  • abductor hallucis tendon: medial aspect of hallux sesamoid complex
  • adductor hallucis tendon: lateral aspect of hallux sesamoid complex
  • considerable variation but mostly branches from the medial plantar artery but often additional branches from the lateral plantar artery as well as a perforating branch of dorsalis pedis 1,2
  • each sesamoid receives a single artery at its proximal pole and there is a general lack of collateralisation, this increases the risk of osteonecrosis and poor fracture healing 4
  • veins correspond to the supplying arteries
  • occurs between 8-10 years of age 1
Anatomy: Lower limb

Anatomy: Lower limb

Article information

rID: 26894
Section: Anatomy
Synonyms or Alternate Spellings:
  • Hallux sesamoid complex
  • Hallux sesamoid bone
  • Hallux sesamoid bones
  • Hallux sesamoids
  • First metatarsal sesamoid
  • Sesamoid of flexor hallucis brevis

ADVERTISEMENT: Supporters see fewer/no ads

Cases and figures

  • Case 1: bipartite lateral and normal medial
    Drag here to reorder.
  • Case 2: hallucal and lesser metatarsal sesamoids
    Drag here to reorder.
  • Case 3: fractured lateral and bipartite medial hallux sesamoid bones
    Drag here to reorder.
  • Updating… Please wait.

     Unable to process the form. Check for errors and try again.

     Thank you for updating your details.