The Sacroiliac Joint is situated at the base of the low back in humans. There are two joints each side that are joined, where one is functionally relevant when sitting and the other is functionally relevant when standing. Those who have an active SIJ syndrome will find sit to stand and stand to sit troublesome, sore and painful. Its the odd internal architecture of the sacroiliac joint that predisposes it to early degeneration (1). Bearing in mind that 37% of people in their 20’s will have spinal disc degeneration without knowing(2). It is no surprise that people experience their first bout of low back pain when they are still young.

What is surprising to most is the intensity of the pain experience associated with a sacroiliac syndrome. The sacroiliac joint is innervated directly from the lumbosacral trunk (L4,5), Obturator Nerve (L2,3,4), Superior Gluteal Nerve (L4,5,S1,S2), Posterior Branch of Spinal Nerves (S1 and S2), and the pelvic branch of the sympathetic nerve. The sacroiliac ligament complex is innervated by nerves from L2,3,4,5,S1,2,3 levels of the spine, that is at least 6 levels of the spine (depending on who you read!). If we consider a spinal facet joint or a spinal disc their innervation is not as widespread meaning they probably aren’t as sore as a sacroiliac joint syndrome experience.

The pain experienced can be across the low back, an intense yet intermittent pain can occur when changing weight bearing posture (ie you need ten seconds before you move once stood up from sitting, or a 10 second pause makes getting out of bed possible, or once sat up the pain shoots for 10 seconds then calms), Pain can be down the leg like in sciatica but also involves the groin and pain can be in both legs or the pain can be only in the groin. It is the variability of the symptom picture that gives it the syndrome part of the diagnostic label, sacroiliac joint syndrome. An in depth description of the sacroiliac joint syndrome can be found in the references(3).

It’s not all about a bad back all of the time, because the pelvis mechanics rely upon the sacroiliac joints working efficiently with the pubic symphysis joint. A joint found at the front of the pelvis behind the mons pubis. Believe it or not pubic symphysis joint dysfunction was written about first in 1870(4). It took another 100 years before the sacroiliac joints were well documented as pain generators in a lower back pain experience.

When evaluating the whole pelvic posture(5) a Chiropractor must consider the sacroiliac joints, the pubic symphysis and differentiate these from the lumbar spine and the hip joints before they can deliver Chiropractic Care. Typically because a sacroiliac syndrome involves ligaments the healing process is slow in the first 2 weeks of Care, to a point that you’d think not much is changing. A sacroiliac syndrome needs safety netting or a watchful eye over the course of 4-6 months before exercises are beneficial to pelvic mechanics in my opinion.

References:

1. Cassidy JD (1992) The Pathoanatomy and Clinical Significance of the Sacroiliac Joints. JMPT 15 (1) 41
2. Brinjiki W et al (2014) Systematic Literature Review of Imaging Features of Spinal Degeneration in Asymptomatic Populations. Am J Neuroradiology DOI: 10.3174/ajnr.A4173
3. Bernard TN and Cassidy JD (1991) Chapter 101: The Sacroiliac Joint Syndrome; Pathophysiology, Diagnosis and Management in Frymoyer JW (Ed) The Adult Spine. Principles and Practice. Raven Press New York.
4. Owens K, Pearson A and Mason G (2002) Symphysis Pubis Dysfunction – A cause of significant obstetric morbidity. Eur J Obs Gynae and Repro Biol 105 143-146
5. Juhl JH, Ippolito-Cremin TM and Russell G (2004) Prevalence of Frontal Plane Postural Asymmetry JAOA 104(10) 411-21