Tough one here (why I saved it for the end of the year). We don’t do much MSK ultrasound but this is something that pops up every once in a while. What if I gave you the history: “Middle aged man starting tennis lessons”

Answer: Tennis leg

There is still debate over the exact pathology and it likely includes several including tears of the plantaris tendon, and what is generally felt more common (currently) which is tearing of the medial head of the gastrocnemius muscle particularly at the musculotendinous junction.

In this case you can see a very heterogeneous medial head of the gastrocnemius without flow consistent with tearing and intramuscular hematoma (note how this looks more like swollen muscle than debris filled cyst aka Baker’s cyst). Note the soleus deep to it. Often you can have fluid/hematoma between the two muscles as well (especially if the etiology is a plantaris tendon rupture)

Here is a picture higher up. Note the complete discontinuity of the medial head of the gastrocnemius

Yes, you can always go lazy and get the MRI (and ortho may want it), but you already know your answer.

Reference (short): http://radiopaedia.org/articles/tennis-leg

Reference (in-depth): http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3060433/

Since I’m already running behind, we will go ahead and take a short summer break till the new folks start.

Seniors, it has been a pleasure to work with you all. Don’t be strangers and if I can ever be of any help, just shout. Good luck to you all. And if you want to continue playing along, just shoot me a message and I’ll stick your email on the list. Unfortunately, unlike my basement, all that stuff you put in there DOES go away if you don’t use it every once-in-a-while.