As the fellows recalled, we often use this painting to remind us that when we are looking at an x-ray, a CT scan or an MRI, we are not looking at the humerus, the glenoid or the rotator cuff. Rather we are looking at an image which incompletely and often inaccurately represents the object of interest. As in:
Ceci n'est pas le sus-épineux
Be sure to visit "Ream and Run - the state of the art" regarding this radically conservative approach to shoulder arthritis at this link.