M71.2: Synovial cyst of popliteal space [Baker]
Cavities like these may be the joint capsule bulging. But such cavities can also form when fluid collects in bursas in the hollow of the knee. Joints are encased in a joint capsule. The joint capsule contains synovial fluid. This enables the bones to slide easily past one another. A bursa is a cushion of connective tissue filled with fluid. For example, there is a bursa beneath tendons or between bones and skin. The bursa prevents the tissue from rubbing together. A bursa also enables pressure to be distributed better.
Fluid-filled cavities in the hollow of the knee can form if the knee becomes inflamed or gets injured, for example. It may be possible to feel the cavity as a swelling in the hollow of your knee. The location may also be painful.
Patient Disclaimer
The information provided on this page is for general educational purposes only. It is not intended for self-diagnosis and does not replace professional medical advice. Always consult your doctor or a qualified healthcare provider with any questions or concerns about your health.
If you see an ICD diagnosis code (e.g., on a medical report), be aware that doctors may also include additional indicators to express diagnostic certainty. Only a healthcare professional can interpret these codes accurately in the context of your individual case.
For a complete understanding of your condition and what the diagnosis means for you, please speak directly with your doctor.