Os trigonum
Last revised by Mostafa El-Feky ◉ on 7 May 2023
Citation, DOI, disclosures and article data
Citation:
Jones J, El-Feky M, Kasáč Z, et al. Os trigonum. Reference article, Radiopaedia.org (Accessed on 25 Sep 2023) https://doi.org/10.53347/rID-10194
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rID:
10194
Article created:
22 Jul 2010, Jeremy Jones ◉
Disclosures:
At the time the article was created Jeremy Jones had no recorded disclosures.
View Jeremy Jones's current disclosuresLast revised:
7 May 2023, Mostafa El-Feky ◉
Disclosures:
At the time the article was last revised Mostafa El-Feky had no financial relationships to ineligible companies to disclose.
View Mostafa El-Feky's current disclosuresRevisions:
37 times, by 15 contributors - see full revision history and disclosures
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Synonyms:
- Os tali accessorium
- Os intermedium tarsi
- Os tali secundarium
- Ossa trigona
The os trigonum (plural: ossa trigona) is one of the ossicles of the foot and can be mistaken for a fracture.
It sits posterior to the talus on the lateral foot radiograph and represents a failure of fusion of the lateral tubercle of the posterior process. It is estimated to be present in ~7% of adults 1. Bilateral os trigona are seen in 2% of individuals 3. The ossicle usually forms between 7-13 years of age and fuses with the talus in a majority of patients by approximately age 17 4, otherwise persisting as an os trigonum.
On this page:
Related pathology
os trigonum syndrome / posterior ankle impingement (PAI) syndrome 1,2
Differential diagnosis
General imaging differential considerations include:
See Also
Quiz questions
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References
- 1. Cerezal L, Abascal F, Canga A et al. MR Imaging of Ankle Impingement Syndromes. AJR Am J Roentgenol. 2003;181(2):551-9. doi:10.2214/ajr.181.2.1810551 - Pubmed
- 2. Karasick D & Schweitzer M. The Os Trigonum Syndrome: Imaging Features. AJR Am J Roentgenol. 1996;166(1):125-9. doi:10.2214/ajr.166.1.8571860 - Pubmed
- 3. Uzel M, Cetinus E, Bilgic E, Karaoguz A, Kanber Y. Bilateral Os Trigonum Syndrome Associated with Bilateral Tenosynovitis of the Flexor Hallucis Longus Muscle. Foot Ankle Int. 2005;26(10):894-8. doi:10.1177/107110070502601017 - Pubmed
- 4. Incidence and Fusion of Os Trigonum in a Healthy Pediatric Population. (2017) Journal of Pediatric Orthopaedics. doi:10.1097/BPO.0000000000001016 - Pubmed
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