Stieda process (not to be confused with a Pellegrini-Stieda lesion) refers to an elongated lateral tubercle of the posterior process of the talus 1,3. It is often considered an anatomical variant.
It forms from fusion of a secondary ossification center at the posterolateral aspect of the talus with rest of the talus (this typically occurs between 7-13 years) where the fused segment remains longer than usual 4.
It is best appreciated on a lateral ankle radiograph or sagittal CT/MRI views.
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Related pathology
- acute fracture of the Stieda process
- it can be associated with posterior ankle impingement syndrome from impingement between the tibia and the calcaneus, especially in plantar flexion. In some symptomatic situations, it is resected 2
Differential diagnosis
It needs to be differentiated from an os trigonum (particularly if partially fused): which refers to a separate bony ossicle at the lateral tubercle of the talus.
History and etymology
It is named after German anatomist Ludwig Stieda (1837–1918) who is considered the first person to describe this in 1869 5.