ABNORMAL POSTURES INCREASE NEURO-CENTRAL COMPRESSION
Deviant spinal alignment can be a potent cause of segmental stiffening. Anomalies can stem from poor postural habits, just as much as from congenital curvatures like spinal scoliosis.
As a rule, spinal segments stiffen more readily in zones where the spine’s function alters; where it changes from neck to thorax to low back. These are called the transition zones and they correspond to where ‘S’ curves (viewed sideways on) change direction. Hence, the common trouble spots in the spine are the lumbosacral level (where the spine joins the fixed pelvis), the thoracolumbar level (where the thorax becomes the lower back), the cervicothoracic level (where the neck joins the thorax) and the atlanto-occipital joint (where the neck joins the base of the skull).
A ROUNDED (KYPHOTIC) LOW BACK
All transition zones give greater trouble if the regular ‘S’bend of the spine deviates too far from normal. However, a fixed kyphotic low back (rounded into a hump instead of a hollow) is particularly troublesome for the neurocentral core because the facet joints at the back take no weight at all. Many spinal levels develop segmental stiffness because of unremitting compression and difficulty in absorbing shock. A fixed kyphosis creates a poorer exchange of fluids through the lower discs. As the spine pile-drivers down into itself, there is a less than vigorous fluid movement because the natural bowing sink-and-spring does not exist. At the time it needs it most, the excessively jarred lower back has to make do with reduced nutrition to carry out vital running repairs. This only heightens the natural attrition of weight-bearing activity and the back wears out faster.Running with a humped low back is an exceptional hazard. The spine cannot bow gracefully into a shock-receiving hollow like a hoop bending as it receives impact, and all the shock is taken up through the neurocentral core.
As your weight descends earthwards through the body, the lumbar segments cannot squelch forward on their discs to dissipate the downward forces. Apart from the incessant jarring which affects the whole frame, there is also no corresponding uplift to spring the spine skywards which can pull up the disc walls. Even walking can be juddering instead of feline and youthful, with the head no longer tracing an imaginary wavy line along through the air as the spine bounces along with every step.
Even the most youthful spines collapse into a ‘C’ shape when sitting, but it is better if they keep a proper lordosis. This applies even more even more when sitting in a vehicle when the added vibration causes greater fluid loss. Accordingly, car seats should have a firm and pronounced upholstered bulge filling out the entire lumbar hollow (to the extent that it feels too much when you first sit down) and the seat should not be tipped down at the back which throws you into slumped sitting on the neurocentral core. Incidentally, the correct horse riding attitude is almost the perfect posture for the back to disperse weight.
Providing the stirrups are the right length, the low back assumes the optimum alignment to ride out shock and balance the upper body over the pelvis. There is another ill effect of lumbar kyphosis. It means that the weight of the upper body is carried too far forward, in front of the line of gravity; the spine cannot stack itself with minimum effort, which causes a ‘turning moment’ (a tendency for the upper spine to move forward)around the thoracolumbar junction.
With the shoulders stooped, the lumbar segments slide forward, jamming the spine at mid-lumbar level. A lumbar-kyphosis creates a similar tendency for the whole body to tip forward on the pelvis, also contributing to the typical ‘bottom out’ appearance.
This is a great source of strain. Pain can emanate from two sites- the bottom and top end of the lumbar spine-at the same time. Upper lumbar problems often refer pain down lower in the back of the lumbosacral junction. When isolating your problem levels it is important not to assume that all your trouble is coming from L5, where the pain is. Both levels must be dealt with if you are to get better.