Jump to content
We need you! See something you could improve? Make an edit and help improve WikSM for everyone.

Accessory Bones of the Foot and Ankle

From WikiSM
(Redirected from Accessory Bones of the Foot)

Introduction

  • Illustration of sesamoids[1]
    Illustration of sesamoids[1]
  • Illustration of accessory bones, lateral view of foot and ankle.[1]
    Illustration of accessory bones, lateral view of foot and ankle.[1]
  • 1 - os subfibulare; 2 - os subtibiale; 3 - os talotibiale; 4 - os trigonum; 5 - os supratalare; 6 - os talus accessories; 7 - os talus secundarius; 8 - os calcanei accessorium; 9 - os calcanei secundarium; 10 - os sustentaculi; 11 - os subcalcis; 12 - os aponeurosis plantaris; 13 - accessory navicular bone; 14 - os supranaviculare ; 15 - os infranaviculare; 16 - os paracuneiforme; 17 - os intercuneiforme; 18 - os cuneometatarsale I tibiale; 19 - os cuneo–I metatarsale-II dorsale; 20 - os cuneometatarsale plantare; 21 - os intermetatarseum; 22 - os peroneum; 23 - os cuboideum secundarium; 24 - os vesalianum[2]
    1 - os subfibulare; 2 - os subtibiale; 3 - os talotibiale; 4 - os trigonum; 5 - os supratalare; 6 - os talus accessories; 7 - os talus secundarius; 8 - os calcanei accessorium; 9 - os calcanei secundarium; 10 - os sustentaculi; 11 - os subcalcis; 12 - os aponeurosis plantaris; 13 - accessory navicular bone; 14 - os supranaviculare ; 15 - os infranaviculare; 16 - os paracuneiforme; 17 - os intercuneiforme; 18 - os cuneometatarsale I tibiale; 19 - os cuneo–I metatarsale-II dorsale; 20 - os cuneometatarsale plantare; 21 - os intermetatarseum; 22 - os peroneum; 23 - os cuboideum secundarium; 24 - os vesalianum[2]
  • Accessory bones: Os Intermetatarseum, Os Supranaviculare, Os Naviculare, Os Supratalare, Os Vesalianum, Os Peroneum, Os Calcaneus Secundarium, Os Trigonum[3]
    Accessory bones: Os Intermetatarseum, Os Supranaviculare, Os Naviculare, Os Supratalare, Os Vesalianum, Os Peroneum, Os Calcaneus Secundarium, Os Trigonum[3]
Illustration of accessory bones of the foot[4]
Sesamoids of the foot. AP radiograph depicting the sites of hallucal (1), interphalangeal joint (2) and lesser metatarsal (3) sesamoids[5]
Hallucal sesamoids. Axial view radiograph of the forefoot shows normal hallucal sesamoids (arrows) and their articulation with the first metatarsal head (asterisk)[5]
Bipartite hallucal sesamoid. The bipartite fragments of the medial hallucal sesamoid are shown. Unlike a normal bipartite sesamoid, the fragments do not fit together perfectly like the pieces of a puzzle[5]
Accessory ossicles of the foot. AP (a), oblique (b) and lateral (c) radiographs depicting the sites of the most common accessory ossicles in the foot. 1 Os trigonum, 2 os peroneum, 3 os naviculare, 4 os intermetatarseum, 5 os vesalianum 6 os supranaviculare, 7 os supratalare, 8 os talotibiale, 9 os calcaneus secundarium[5]

General

  • Accessory ossicles and sesamoids of the feet are common anatomic variants
  • They vary widely in their prevalence and appearance
  • Symptomatic accessory and sesamoid bones are rare

Definitions

  • Ossicle: accessory bone that is usually a normal variant with no known function
  • Sesamoid: small flat bone usually embedded in a tendon or joint capsule

Sesamoid Bones

  • Hallucal Sesamoids
    • Always present on the plantar aspect of the first metatarsal head
    • Medial sesamoid can show bipartite variation[6]
  • Lesser Metatarsal Sesamoids
    • Can occur from the 2nd to the 5th metatarsal
    • Appear embedded in the plantar aspect of the joint capsule
    • May be multiple or multipartite
    • Prevalence: second (0.4%), third (0.2%), fourth (0.1), fifth (4.3%)[7]
    • Pathology associated with these is rare
  • Interphalangeal Joint Sesamoid of the Great Toe
    • Occurs at the plantar aspect of the interphalangeal joint of the first digit
    • Embedded within the joint capsule
    • Presence can alter biomechanics, limit motion[8]
    • Prevalence reported between 2 and 13%, however post mortem studies up to 73%[9]
    • It can be traumatically interposed into a dislocated IP joint, making it irreducible

Ossicles

General

  • Most common: os trigonum, os peroneum and os naviculare[10]
  • Less common: os intermetatarseum, os vesalianum, os supranaviculare, os supratalare, os talotibiale and os calcaneus secundarium

Os Trigonum

Os Peroneum

  • Located in the cuboid tunnel, near the calcaneocuboid joint, embedded in peroneus longus tendon
  • Present in everyone in cartilage form, ossicle forms in 26% of population[12]
  • Bipartite 30% of the time, bilaterally 60% of the time[12]
  • Can become painful and symptomatic

Os Naviculare

  • Also terrmed accessory naviculare
  • There are three morphologies/ variants
  • Second most common accessory bone of the foot, prevalence 2 to 21%[13]
  • Bilateral in 50% of cases

Os Intermetatarseum

  • Most commonly located between the first and second metatarsal
  • Radiographic studies show prevalence of 1-7%, cadaveric studies up to 13%
  • Rarely has associated pathology
  • May be confused as a fracture (such as in a lisfranc injury)

Os Vesalianum

Os Supranaviculare, Os Supratalare and Os Talotibiale

  • Rare series of ossicles located dorsal to talus[15]
  • Os supranaviculare can fuse with navicular
  • Rarely associated with painful conditions

Os Calcaneus Secundarium

  • Between the anteromedial aspect of the calcaneus, cuboid, the talar head, navicular
  • Incidence reported between 0.6% and 7%[16]
  • Difficult to see on xray, seen on CT
  • Has not been shown to be clinically relevant

Os Subfibulare

  • Accessory ossicle that lies at the tip of the lateral malleolus
  • Typically asymptomatic and incidental finding

Os Subtibiale

  • Rare accessory ossicle found at the posterior colliculus of the medial malleolus[17]
  • Typically asymptomatic and incidental finding

Pathological Conditions

Trauma

  • Can simulate fracture of neighboring bone or fracture themselves
  • Radiographic findings
    • Due to small size, can be difficult to identify radiographically
    • Acute: well corticated with smooth borders
    • Fracture: irregular fragment with poorly corticated margins
  • Additional clues
    • Evidence of displacement
    • Presence/ absence of donor site
    • Soft tissue swelling
  • hallucual sesamoids more prone to fracture, medial > lateral[18]

Sesamoiditis

  • Characterized by chronic pain at the hallucal sesamoids
  • May be due to stress fracture, stress reaction, osteoarthritis, osteonecrosis, tendinosis, capsular inflammation

Infectious

  • Osteomyelitis most commonly occurs due to direct extension
  • For example, sesamoid hallux may be infected secondary to extension from soft tissue infection or septic arthritis

Degenerative Disease

  • Hallucal sesamoids articulate with metatarsal head, susceptible to osteoarthritis
  • Findings: loss of joint space, subchondral sclerosis and cysts, and osteophyte formation

Clinical Significance

See Also

References

  1. ↑ 1.0 1.1 Kobashi, Y., Y. Tazawa, and S. Suzuki. "Disorders of the accessory bones and sesamoids of the foot and ankle." European Congress of Radiology-ECR 2010, 2010.
  2. ↑ Keles-Celik, Nigar, et al. "Accessory ossicles of the foot and ankle: disorders and a review of the literature." Cureus 9.11 (2017).
  3. ↑ Osiowski, Aleksander, et al. "The prevalence and clinical considerations of Os Vesalianum Pedis: A meta-analysis." Foot and Ankle Surgery (2025).
  4. ↑ Case courtesy of Andrew Murphy, Radiopaedia.org, rID: 99467
  5. ↑ 5.0 5.1 5.2 5.3 Nwawka, O. Kenechi, et al. "Sesamoids and accessory ossicles of the foot: anatomical variability and related pathology." Insights into imaging 4 (2013): 581-593.
  6. ↑ Munuera, Pedro V., et al. "Bipartite hallucal sesamoid bones: relationship with hallux valgus and metatarsal index." Skeletal radiology 36 (2007): 1043-1050.
  7. ↑ Coskun, Nigar, et al. "Incidence of accessory ossicles and sesamoid bones in the feet: a radiographic study of the Turkish subjects." Surgical and radiologic anatomy 31 (2009): 19-24.
  8. ↑ Roukis, Thomas S., and Jeffrey S. Hurless. "The hallucal interphalangeal sesamoid." The Journal of foot and ankle surgery 35.4 (1996): 303-308.
  9. ↑ Davies, M. B., and S. Dalal. "Gross anatomy of the interphalangeal joint of the great toe: implications for excision of plantar capsular accessory ossicles." Clinical Anatomy: The Official Journal of the American Association of Clinical Anatomists and the British Association of Clinical Anatomists 18.4 (2005): 239-244.
  10. ↑ Lawson, Jack P. "International Skeletal Society Lecture in honor of Howard D. Dorfman. Clinically significant radiologic anatomic variants of the skeleton." AJR. American journal of roentgenology 163.2 (1994): 249-255.
  11. ↑ Karasick, David, and Mark E. Schweitzer. "The os trigonum syndrome: imaging features." AJR. American journal of roentgenology 166.1 (1996): 125-129.
  12. ↑ 12.0 12.1 Sobel, Mark, et al. "Painful os peroneum syndrome: a spectrum of conditions responsible for plantar lateral foot pain." Foot & Ankle International 15.3 (1994): 112-124.
  13. ↑ Stoller, D. W. Magnetic resonance imaging in orthopaedics and sports medicine. Lippincott Williams & Wilkins, 2007.
  14. ↑ Boya, Hakan, et al. "Os vesalianum pedis." Journal of the American Podiatric Medical Association 95.6 (2005): 583-585.
  15. ↑ Tsuruta, T., et al. "Radiological study of the accessory skeletal elements in the foot and ankle (author's transl)." Nihon Seikeigeka Gakkai Zasshi 55.4 (1981): 357-370.
  16. ↑ Mellado, J. M., et al. "Accessory ossicles and sesamoid bones of the ankle and foot: imaging findings, clinical significance and differential diagnosis." European radiology 13 (2003): L164-L177.
  17. ↑ Coral A. The radiology of skeletal elements in the subtibial region: incidence and significance. Skeletal Radiol. 1987;16 (4): 298-303.
  18. ↑ Karasick, David, and Mark E. Schweitzer. "Disorders of the hallux sesamoid complex: MR features." Skeletal radiology 27 (1998): 411-418.
Created by:
John Kiel on 7 November 2024 22:23:30
Authors:
Last edited:
6 February 2026 00:37:01
Categories:
Retrieved from "https://wikism.org/w/index.php?title=Accessory_Bones_of_the_Foot_and_Ankle&oldid=40427"