A 38-year-old man presents with a 3 cm, soft, fluctuant swelling on the left dorsal wrist. The lump is non-tender and transilluminates when light is shined through it. He has no history of trauma or infection.He is a college professor and uses his left hand to write on the black board. Which of the following is the most useful initial diagnostic tool for confirming a ganglion cyst?
