When I was younger I was able to crack my knuckles almost any time I wanted. I could also crack my back easily by leaning backwards in a low back chair. As I have gotten older I have all but lost both of those abilities. I think my spine has compressed eliminating the flexibility to do that and arthritis has filled the extra space in my knuckles. Never fear, my knees have picked up the slack. It sounds like popcorn when I walk upstairs.
