When we have structural facet dysfunction, we will usually see a loss of muscle control. The muscles need to return back to their resting state after being used. If they cannot they begin to compress their related structures. Remember afferent signals are your sensory neurons. So once the information gets up to the brain, or cortex or cerebellum that information is processed and interpreted mainly in the parietal lobe which is kind of our thinking portion which will be compared to the information in your temporal lobe which is kind of the memory portion then that information is going to be coordinated with the cerebellum. That information is then sent to the frontal lobe and that comes back down and alters our cortisol spinal pathway or gate. Remember frontal lobe is motor.
With alteration to afferent stimuli to the joints and mechanoreceptors and related soft tissues, results in dysfunctional muscle activity and can alter vertebral biomechanics. Mechanoreceptors do not create pain by themselves. But they set up afferent loops that tend to hyperexcite the surrounding musculature. When the 4th layer musculature is hypertonic on one side, they can rotate the vertebrae to the opposite side. This is what causes the facets to lock closed on the ipsilateral side and open the contralateral side. The intertransversarii tends to sidebend the adjoining vertebrae and lock them closed while multifidus and rotatores rotate the vertebrae to the opposite side.
So, if you have a segment that is sidebend and rotated to opposite sides this is considered what? A Type 1 group curve. So just like we discussed the muscles pull and lock the facets. So, you can have a segment in the spine that is sidebend right and because of the rotatores we just discussed the segment will also be rotated left. So sidebend right rotated left. This is also seen in scoliotic patterns but remember sometimes these patterns are just compensations to other dysfunctions.
When it comes to ribs when the facets are stuck open or closed the vertebrae reacts by sidebending and rotation. In the thoracic spine rotation and sidebending are coupled to opposite sides, the rib above and below must move too. Rotation on one thoracic vertebra on top of another causes a torsional movement in the ribs in which one rib turns externally while the other turns internally. So, when there is facet dysfunction the rib head sometimes loose the smooth natural movement and can become slightly subluxed. A rib stuck in external rotation is usually caused by a facet on the same side is stuck closed. If you palpate out to the rib angle to check for tenderness and there is tenderness this is probably a sign to rib dysfunction.
If you’re a therapists or clinician and use manual therapy techniques or functional training take these ideas into the clinic with you. It is very important to catch these patterns before they become painful patterns. Assess and look for joints not opening or closing, what compensations are they having because of this. Just because someone has pain between the shoulder blades does not mean you need to plow down on that area. Test for spine and rib dysfunction.