Ouch

We had a mishap in our lesson on Friday, and once again I can tell you that I was saved by my helmet, on a day on a horse where some people might think it wasn't needed.
My sweet, calm, trained ten year old was doing a lovely canter up the long side in the indoor. It was a quiet, sunny day and I was having a lesson.
Suddenly with no warning he tripped and went down hard. I slammed into the 2 X 6 rough cut kick wall with my head and arm. I'm unharmed except for a badly bruised arm, but without a helmet it would have been a different story.
Rogo's left front is slightly swollen. He hit it with a back foot and it's scraped a bit. He's on bute and is going to have a few days off. Fingers crossed he heals quickly and well.
I'm not sure what caused his fall. I went back to look at the hoof prints and I could clearly see the step he took where he went down. There was a small rock inside the hoof print. Joan, my teacher, thought the stone must have rolled. Maybe it hurt his foot. I really don't know so that's kind of scary.