Os calcaneus secundarius

Case contributed by Dr Craig Hacking


Pain after football injury. X-ray ? navicular fracture.

Patient Data

Age: 20 years
Gender: Male

No fracture identified. Incidental accessory navicular bone and os calcaneus secundarius. Alignment is normal.


There is a possible undisplaced transverse fracture through the medial aspect of the navicular on the AP projection which represents a typical type II os tibiale externum and not a fracture, as the margins are smooth and well-corticated, as well as in a typical location for this ossicle. This is what led to the CT.

Case Discussion

This ossicle can simulate an intra-articular fracture.

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Case information

rID: 36715
Case created: 6th May 2015
Last edited: 31st Dec 2017
Inclusion in quiz mode: Included

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