Teenager 11 years-old from the surgeon with suspected hygroma of popliteal fossa, in history there is fall from altitude of several floors visually there is a complex scar in the two-thirds of leg thru the popliteal fossa to the shin.
At US in the popliteal fossa there is nothing but in the infrapatellar region (Hoffa' s fat pad) a small amount of liquid (bursitis?).