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The L/S Junction, the key to spinal mechanics

The L/S Junction, the key to spinal mechanics

L/S Junction recalibration

Saul Yudelowitz BSc (Hons)


In the picture on the left you are looking at the spine from the side while this patient is lying down on their back. The L/S junction is formed between the Sacrum (the triangle bone at the bottom) and the lumbar vertebra above (There are 5 Lumbar vertebra). This angle forms the foundation of the mechanics entire spine, the last Lumbar vertebra and the triangle sacrum. In the picture (X-Ray) there is a pathological issue however the purpose is to understand the angle that the L/S junction forms.

The spaces between the vertebras are where the discs are found. As you can see, the lower down the spine we go the higher the disc height gets as it has more weight to bear. What is also interesting is the shape of the disc at the L/S junction: wedge shaped!

As the spine is bent forward, as in bending down to touch the toes, the higher part of the wedge shape disc is compressed resulting in an exponential increase in pressure at the narrow end of the disc. This pressure is exerted from the inside towards the outside of the disc and hence the reference to a prolapsed disc.

The point is that if you maintain this bent spinal position for prolonged periods you will eventually begin a process of degenerative disc disease (DDD). Sitting on a chair at work for long periods in this position is one such causative factor. In the gym, bending down with a rounded lower back to lift weights up during exercise is an excellent way to get DDD. If your personal trainer allows you to do this fire them on the spot immediately! DDD is characterized by a decrease in disc height!

At Health and Performance we have measured the height of the discs,  pre and post stretching. We have always found an increase in disc height after our MOD stretching methods have been applied. This results in spinal decompression. Please do remember that the human body is about balance and nothing in extreme works in the long run. If the L/S junction is over arched this will eventually lead to degenerative joint disease (DJD). The joints of the spine are referred to as facet joints. The facet joints are formed just below the vertebra when looking at the spine from the side. DJD is typically characterized by osteophyte formation and then arthritis. While everyone’s curve is unique to them there is of course no one size fits all approach. We ideally would like to keep the L/S junction between the two opposing ranges of movement and when movement occurs we are the ones who controls this, not the joint or disc stopping the movement!
This needs to be learnt and understood from a kinesthetic perspective. Tight muscles will affect the movement of joints and clinically it is common to see patients not able to place the L/S junction in the correct position and therefore work higher up the spine to compensate for this. Typically and area of the spine that is overworked leads to DJD. This is one of the main reasons medically we will see an increase in DJD of the spine in the lower thoracic area in the next 8 – 10 years.
Since the L/S junction affects the entire spinal mechanics, it is essential that this is corrected so that long term health of the spine can be achieved and maintained. Enjoy what you have and don’t take it for granted. If you look after your spine it will look after you well into old age!
Feel free to contact us if you would like any additional infomation.
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