The popliteus bursa: an indicator of subtle pathology.

The abnormal contour of the popliteus bursa, as examined on double-contrast arthrography, is an indicator of numerous disorders of the knee. Narrowing, compression, or complete absence of the popliteus bursa is associated with tears of the lateral menisci and with discoid menisci. Absence of the popliteus bursa can also be indicative of adhesive capsulitis, prior surgery, or a rare congenital anomaly. In addition, the popliteus bursa is a reservoir for intraarticular loose bodies. Normal variations of the popliteus tendon can also be observed arthrographically. Anatomic variants and abnormalities of the popliteus bursa are presented with emphasis on the spectrum of possible arthrographic findings. The detection of popliteus bursa abnormalities during arthrography should prompt further detailed examination. The embryology and anatomy of the popliteus bursa are reviewed.