#3 is correct- Prepatellar bursitis with bone spur
This is likely a chronic prepatellar bursitis. There is a bone spur on the patella. The more posterior situated patellar tendon appears intact.
NOTES: This study should always have long axis (LAX) and short axis (SAX)for comparison. Color or Power Doppler would have been very useful to help correlate inflammation. Care must be taken to "float" the transducer over the skin, see gel pad on image "A". Floating the transducer mitigates displacement of the fluid medially and laterally and, when using Doppler assures light transducer pressure allowing for insonation of the inflammatory vessels.
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