Functional problems are those in which muscles or joints do not move optimally, creating stress to the tissues. In my opinion, functional problems lead to structural diagnoses (diagnoses describing physical changes in the body such as a bulging disks or arthritis) and pain. This may occur due to faulty movement patterns, weakness, limited range of motion, old injuries, or all of these factors. I believe the repeated stress from functional problems leads to physical changes in the body such as herniated or bulging disks and facet -- in other words, structural diagnoses.
Find out more about this book:Fixing You: Back Pain: Self-Treatment for Sciatica, Bulging and Herniated Disks, Stenosis, Degenerative Disks, and other diagnoses.