Low Back Pain Definitions

The definition of low back pain should not be ignored, and a topographical description is preferred. Starting with the wrong topographical area can lead to the wrong diagnosis. A topographical definition makes no assumption as to cause of the pain, only its location.

The importance of having clear definition has been demonstrated in a 1989 study. They found the interobserver reliability of defining a patients pain pattern as being in the "back" to be very poor (Kappa 0.16). Defining the pain pattern as "buttock pain" had moderate agreement (Kappa 0.44); foot pain, leg pain, and thigh pain all had good agreement (Kappa 0.73, Kappa 0.96, and Kappa 0.78 respectively)

Low Back Pain

The IASP taxonomy does not recognise the term "back pain," rather it categorises it into lumbar spinal pain and sacral spinal pain. There is also an overlapping definition called lumbosacral pain. These three categories constitute the colloquial term "low back pain." Another overlapping definition is thoraco-lumbar pain, but this is not low back pain. The IASP taxonomy are periodically updated, so to get the latest definition go to IASP and in part I (topics and codes) click on "spinal pain, section1: spinal and radicular pain syndromes." The definitions here are up to date as of August 2021.

Lumbar Spinal pain

"Pain perceived as arising from anywhere within a region bounded superiorly by an imaginary transverse line through the tip of the last thoracic spinous process, inferiorly by an imaginary transverse line through the tip of the first sacral spinous process, and laterally by vertical lines tangential to the lateral borders of the lumbar erectores spinae. Pain located over the posterior region of the trunk but lateral to the erectores spinae is best described as loin pain to distinguish it from lumbar spinal pain. If required, lumbar spinal pain can be divided into upper lumbar spinal pain and lower lumbar spinal pain by subdividing the above region into equal halves by an imaginary transverse line."

Sacral Spinal Pain

"Pain perceived as arising from anywhere within a region bounded superiorly by an imaginary transverse line through the tip of the first sacral spinous process, inferiorly by an imaginary transverse line through the posterior sacrococcygeal joints, and laterally by imaginary lines passing through the posterior superior and posterior inferior iliac spines."

Lumbosacral Pain:

"Pain perceived as arising from a region encompassing or centred over the lower third of the lumbar region as described above and the upper third of the sacral region as described above."