I use a reflex hammer for reflexes, especially in kids. You definitely can use your hands too but it takes more skill and practice that I don't have.
It's like the grizzled old attending who's forgotten more than you'll learn over your entire career, going about the physical exam like a master craftsman. Using their hands, eyes, ears, nose to diagnose.
I'll probably never be at that level of skill either, but man it's cool to watch and read about.