Wow, well good thing no one was seriously hurt! I've been on a trail ride and saw one of my best friends get badly injured.
We were trail riding out at Normandy and there's this one big pull that you have to take one at a time. I was the first up, and once I reached the top...I went to turn my horse to wait and I heard him holler out and then heard the rest of the group start yelling. When I looked he was on the ground not moving and his horse was just trying to stand up.
His horse had reared half way up the hill and had fallen backwards on top of him. He broke his colar bone, shattered his knee, broke both legs and one arm, broke all of his ribs and one puncutred his lung. He is fine now, but has limited use of his left arm, he can't bend it all the way out. He still rides with us today, but since then I've been so much more cautious.