A 35 y/o male come to the ED because of pain in his right shoulder, he refers the pain started some month ago during a tennis match, the pain continued but it wasn't so high so he kept playing in the last months, now it is worse. "My tennis mate told me I should perform a magnetic resonance, because it might be a rotator cuff disease" (RCD).
You listen to the patient but decide first to act as a physician and make the old and fascinating physical examination...
What you find is a normal movement of the shoulder, no pain in abducting the arm (arch test), no weakness or pain in internal and external rotation. (see video)
And so what?
Shoulder pain is the third most common musculoskeletal reason for seeking medical care, affecting between 7% and 26% of adults at any time.
The prevalence of rotatory cuff disease in a population of less than 70 y/o is 2,8 to 15%. Has our patient is a tennis player we can assume he has a pretest probability of about 10%, so in this case the post test probability drop to 0,4%...we may skip magnetic resonance for this time.