THE OS TRIGONUM SYNDROME - IMAGING FEATURES

The os trigonum syndrome refers to symptoms produced by pathology of t he lateral tubercle of the posterior talar process, Pain can be caused by disruption of the cartilaginous synchondrosis between the os trigo num and the lateral talar tubercle as a result of repetitive microtrau ma and chronic inflammation. Additional etiologies include trigonal pr ocess fracture, flexor hallucis longus tenosynovitis, posterior tibiot alar impingement by bone block, and intraarticular lease bodies. This pictorial essay explores the role of imaging modalities in the diagnos is and treatment of the os trigonum syndrome, a symptom complex that m ay present difficult diagnostic problems.