My guess is the Ulnar nerve. I pinched both of mine at IMAZ in 06. It was horrid. I had claw's for almost two months, tho it did eventually get better.
Ironically I had scheduled my yearly "womanly" doctors appt for the week after Ironman, so my doc checked me out then. Said there wasn't anything I could do. She also warned me to change my riding style/position.
I'm very careful now.