Baker’s Cyst

axial CT of Baker\'s cyst

67 year-old female with right knee pain. A Baker’s cyst is seen between the medial head of gastrocnemius and the tendons of semimembranosus and semitendinosus. The tail of the cyst is seen directed toward the knee joint. There is no surrounding inflammatory change to suggest rupture. Otherwise known as popliteal cyst, a Baker‘s cyst is typically located behind the medial condyle, between the medial head of gastrocnemius and the semimembranosus tendon. It usually communicates with the knee joint posteromedially, and fluid from a knee joint effusion may extend into the cyst. There is a strong association with intraarticular pathology such as rheumatoid arthritis, osteoarthritis, trauma or infection.

Reference: Diagnostic Imaging: Orthopaedics. Stoller, Tirman & Bredella 2004

Credit: Dr Laughlin Dawes