Pop in forearm

I was warming up just throwing with someone and on my first throw over 60% effort something in my upper forearm felt like it popped and then my fingers went numb for maybe a second. But then I could resume throwing, no loss of velocity or control throughout the rest of the day, and hit fine. What was this? Even right now probably 5 hours since this happened I can move my arm fine, throw a ball with no pain, and have no numbness.