Thirty-seven years ago while a chiropractic student, I was told that a low PSIS level (posterior inferior iliac spine) was an indicator of sacroiliac dysfunction. More specifically, the left PSIS is low and the right PSIS is higher; the PSIS levels bilaterally are not even.
Over the years, I have come to other conclusions through observations of relationships between sacroiliac function and dysfunction at higher levels. I have written on these relationships in previous articles, but would like to share additional observations here.
Seated Observations
It started with the repeated seated evaluation of PSIS levels and the frequent observation of a lower left PSIS level and a higher elevated right PSIS level. Never do I recall finding a higher left PSIS level and a lower right PSIS level in the seated position. With prone static palpation, the left PSIS also is lower than the right side. The lower PSIS level can be 1/8th, 1/4th, 1/2 or 1 inch lower.
With seated forward lumbosacral flexion, the left ilium does not move upward, but the right ilium moves increasingly upward. This is monitored by palpation of the PSIS levels during seated forward lumbar flexion. Adjustment to the left ilium with contact at the left PSIS can result in audible release, but not always a change in PSIS levels. However, adjustment at the C1 or C2 level (and sometimes cervical traction) will normalize sacroiliac function and even out static PSIS levels. In other words, forward flexion allows left ilium forward and upward motion, and standing may allow posterior ilium motion with hip flexion.
Other relationships also can be involved, such as lumbar and thoracic dysfunction. Each of these levels, with dysfunction or excessive compression, can affect sacroiliac motion. Of course, with SI dysfunction, there will be potential consequences of hip and knee stress.
Conclusions and Solutions
Back to lower left PSIS levels: In my experience, almost all cases of seated low PSIS levels on the left are corrected with upper cervical manipulation or traction, but mainly C-1 or C-2 manipulation. To cut the story short, such manipulation or traction occasionally results in mild adverse reactions to the left neck and cervicothoracic regions. However, surprisingly, vigorous massage to the left upper trapezius muscle causes a normalization of PSIS levels and a lessening of upper cervical dysfunction.
My conclusion is the educated guess that the hypertonic upper trapezius muscle shortened and pulled on the occiput, causing cervical compression and C1/2 reactive dysfunction. Adjustment to C1 or C2 on the left side or upper trapezius massage in the presence of uneven PSIS levels results in level PSIS levels and normal SI function with lumbosacral forward flexion. This was a long stretch from my earlier years. I must emphasize that palpation skills are at the root of evaluating such relationships.
Dr. Joseph Kurnik practices in Torrance, Calif. He is a former columnist and longtime contributor to DC; previous articles are available online at www.dynamicchiropractic.com.