Synovial Cyst (Baker’s Cyst)


A Baker’s cyst is a benign synovial swelling which was initially named by William Morrant Baker in the 19th Century. There are two types of Baker’s cyst, namely primary and secondary cysts, which are explained below:

Located at the back of the knee, between the medial head of the gastrocnemius muscle and one of the medial hamstring muscles (semimembranosus), lies a bursa. This bursa can become distended due to a build-up of synovial fluid. This build-up of fluid is termed a primary Baker’s cyst and occurs in healthy knee joints, thought to be due to communication existing between the synovial joint of the knee and the bursa.


Another more common subtype of Baker’s cyst is termed a secondary Baker’s cyst . This Baker’s cyst occurs in patients who have a pre-existing knee complaint such as osteoarthritis. In these patients, the underlying knee complaint causes excess synovial fluid to build up in the knee joint, leading to the distension of the synovial capsule into the back of the knee and the characteristic swelling observed.




Baker’s cysts can vary in symptomatology, ranging from no symptoms at all to discomfort/tightness around the back of the knee and pain/limited movement when bending the knee. Similarly, there may be no observed swelling or very obvious distension at the back of the knee due to the presence of a larger Baker’s cyst. In a minority of patients, Baker’s cyst can rupture leading to drainage of the fluid into the calf. In these cases, it is necessary to be thoroughly assessed to rule out a deep vein thrombosis. Baker’s cysts can be removed either by draining the excess fluid or through surgery.

(The list of conditions given above and subsequent explanations are intended as a general guide and should not be considered a replacement for a full medical examination. Furthermore, we do not purport to treat all the conditions listed. Should you wish to discuss any of these conditions with our chiropractors, please do not hesitate to phone the clinic on 020 7374 2272 or email

Our team of chiropractors and massage therapists are on hand to answer any questions you may have, so get in touch today via or on +44 (0)20 7374 2272.

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