If you break your arm in O'Cebreiro (which you won't as you will not be going there!), you will walk 21km the next day to Triacastela, thinking that it's just a strain. That will be Sunday and so nothing will be open. You will wait until Monday morning and go to the medical centre, because by now you will really suspect there is something wrong.
They will send you to Sarria, which you will do in a taxi while the rest of the family walks. You will be seen by a very nice doctor, have some xrays taken and then be sent to the hospital at Lugo. You will manage to find a bus to take you there. Then a taxi to the hospital. At this stage you may or may not get very lost trying to find the right department. You will also wish you had your passport and had not left it with the husband. Furthermore you will wish you could say more than hola, gracias and peregrina. By the end of the day you'll have worked out urgenxia, fractura and a number of other medical terms that will triple your Spanish vocab. You will also have worked out that everyone says hi to everyone else when they enter a waiting room. You'll take a taxi back to Sarria because you think you've put your daughter through enough for the day and it would be a long wait for the bus. You'll be ever so grateful that the taxi driver is honest and tells you it is going to be expensive (well you think that's what he said), but by this stage you really don't care. You'll then take a rest day in Sarria and when you get home the insurance will cover it all, right down to the restaurant meal for dinner!
That's what happened for us anyway. It was my 8year old who broke her arm simply falling over on the path by the albergue and she did it again six months later falling off a wall at home - it was much more fun in Spain!