The lower portion of your back aka the lumbosacral spine is the most common to have injuries or pain. An average of 45% of people have acute lower back pain. Not too many see a doctor. If lower back pain continues for a long period of time one should go see a doctor because it can lead to more severe or chronic back problems. Several things can be going on to cause your lower back pain, such as: compressions, disk bulging, spinal nerve decompressing, etc. Mri and Ct are used to diagnose most of these problems Here are a few images that I received from http://www.backandneck.about.org/
