After Dwayne mentioned it, I knew it was right and that I had heard it somewhere before. I went over my notes from paramedic classes and it is one of the S & S that we were taught for PE. My classes were taught by a true legend in the state, #5 NREMT-P, masters degree, 30 years in the field and instruction. This is a teacher that is now in the classroom 2 days a week and on clinicals 3 days a week in a busy ED. I can't specifically cite references for where he comes up with this as a S and S of PE, but I would bet your life on it ;-)
Take care.