More physicians are offering a different perspective on paintings by ‘diagnosing’ pieces of art.

When it comes to art, beauty is in the eye of the beholder. And so, apparently, is a medical diagnosis.

Rheumatologist Sara E. Walker spent her life doing research on and treating patients with lupus and other conditions. When she saw a picture of Italian Renaissance painter Raphael’s “The School of Athens,” she couldn’t take her eyes off the lone figure sitting on the stairs off to the side from the other philosophers, his solemn face looking downward.

The figure in the painting was Heraclitus, the Greek philosopher. Many art historians believe the portrait is based on Raphael’s contemporary and rival, Michelangelo—just one of the reasons the work is so famous.

But Dr. Walker says the figure caught her attention for a different reason.

“He doesn’t have a normal knee,” she says. With a physician’s trained eye, she immediately noted the swollen joint and the unusual lumps and bumps around the knee cap.