Should I be concerned about my cat?

I went to pick up my cat today and as I has holding him, one claw got stuck in my shirt. I tried to unhook it ASAP but he panicked and twisted away, bringing me to the floor with him. I accidentally kneeled on his tail for a couple seconds while frantically trying to unhook it and the noise sounded HORRIBLE.

After a few minutes he was back to letting me pet him, purring, and cuddling me, but I'm still worried I hurt him. Granted I don't weigh much(125 pounds) and I wasn't putting my entire weight on my knee, but I still hear cats can get spinal injuries and broken tails from stuff like this. And that they're very good at masking pain too. Should I be worried even though he seems normal? Also if it matters, he's 17 so he's pretty old.