So ultrasound had, shows bruising clearly as a blob between layers, which is why it looks odd (it looks like I have an egg under there) - apparently caused by the sort of impact (dragging rather than straight on if that makes sense) causing separation of the layers which then fills with blood…
I forgot the name they called it but it’s not common so I guess I made someone’s day
Anyway now home showered and the lower half of myright arm is in a pressure bandage till the swelling goes down