Discussion of Popliteal cyst
- AKA Baker's cyst
- A popliteal cyst is fluid distention of a bursa between the gastrocnemius and semimembranosus tendons via a communication with the knee joint.
- Fluid within a Baker's cyst may communicate freely with the knee joint. However, the presence of a valvelike mechanism may allow joint fluid to communicate in only one direction.
- Popliteal cysts may be seen with many joint abnormalities, such as internal derangement, osteoarthrosis, or inflammatory arthritis; the most common associations include joint effusion, meniscal tear, and degenerative joint disease.
- Potential complications:
- Pseudothrombophlebitis syndrome (rupture, dissection)
- Deep vein thrombosis
- Posterior compartment syndrome
- Trapped calcified bodies
 Imaging Findings for Popliteal cyst
- Fluid between the medial gastrocnemius and semimembranosus tendons is characteristic on sonography.
- Popliteal cysts are T2 bright on MRI.
Patient #1: MR images demonstate a large popliteal cyst
 See Also
 External Links
 References for Popliteal cyst
- E-medicine Baker cyst article.
- Ward, Eric E., Jacobson, Jon A., Fessell, David P., Hayes, Curtis W., van Holsbeeck, Marnix. Sonographic Detection of Baker's Cysts: Comparison with MR Imaging. Am. J. Roentgenol. 2001 176: 373-380.