To be completly honest, my worst fall wasnt actually invloving me falling off, but instead my mum.
I was giving her a lunge lesson on my 15.2hh TB, Foxy. Starting at walk we soon desided to go for a trot, Foxy does about 2 steps at a trot and does 2 very true bucks. Mum still learning couldnt sit it and was flung over his head and she landed soooo hard :( she was basicly flung up off Foxy then just came straight down and hit the ground and wasnt moving at all. I had freaky thoughts going through my head at that moment, ran over to her and kinda rolled her so I could see her face. And omg I will never forget the expression on her face

she was so spooked and gasping because she was winded.
After a few mintues of getting her breath back she sat up and said her shoulder was sore, I took a look and said I think you dislocated it or somthing, as a bone was sticking out. So off we rushed to hospital :( Turned out it was a broken collar bone.
She's all healed up from it now, but that was the scariest one for me. Seeing mum come off and just not move at all. I have seen friends and cousins come off and stuff but something about it being mum made it the most horrible fall out of all mine combined.