09/11/2025
Ever noticed this tiny extra bone behind the talus? 👀
That’s the Os Trigonum — a normal accessory bone found in some people, visible here beautifully on X-ray, CT, and MRI.
Though usually harmless, it can sometimes cause posterior ankle pain or Os Trigonum Syndrome in athletes and dancers 🩰⚽
📸 Modalities:
1️⃣ X-ray – clearly showing the bony outline
2️⃣ CT – precise bone detail
3️⃣ MRI – soft tissue evaluation and inflammation check
---
🩻✨ Radiologist’s Point of View:
The Os Trigonum is an accessory ossicle located posterior to the talus — often a normal variant but clinically significant when symptomatic. ⚠️
On X-ray, it appears as a small, well-corticated bone separate from the talus.
CT defines its cortical margins in detail, helping differentiate it from a posterior talar process fracture.
MRI is the gold standard to assess bone marrow edema or adjacent soft tissue inflammation — key findings in Os Trigonum Syndrome.
Understanding this small structure prevents misdiagnosis and ensures accurate reporting! 🧠💡
💡 Radiology reveals more than the eye can see!
