We assume poor postures for greater amounts of time than we used to, predominantly due to hi-tech gadgets. Sitting a lot in bad positions puts an unnatural load on the lumbar discs, the building blocks of our spine in our lower back. Issues with lumbar discs are debilitating but are surprisingly simple to avoid. If you don’t sit much and your work involves manual labour don’t skip this chapter! Repeated lifting can have the same effect on the lumbar discs as sitting in poor positions.

Anatomy made easy

The spine is made up of a stack of blocks of bone called vertebrae. These vertebrae are categorised into three groups: cervical (neck), thoracic (mid-back) and lumbar (lower back).

Looking at the spine from side, it easy to see it is built with natural mild curves: in at the neck, out over our shoulder blades and back in again at our lower back. From the front or back our spine should be nice and straight.

We have discs sandwiched in between each of the vertebrae in our spine, which are fused to the vertebra above and below. The discs act like a cushion or shock absorber. The presence of these discs combined with the natural curves of our spine work like a spring to absorb the impact and shocks that are imposed on our body from natural movement. The ultimate role of all of this shock absorption is to protect our most precious structure––the brain.

The discs in the spine are made up of concentric rings of fibrous tissue surrounding a pocket of jelly in the centre. Picture a jam donut––a sugary dough casing a heart full of jam in the middle. This is similar to our disc structure (though I’d imagine they don’t taste nearly as good). The discs are springy, and the jam in the middle allows the disc to compress slightly if the spine is loaded.

When our spine is in the upright or straight position, the lumbar spine (lower back) has a natural inward curve. When the lumbar spine is positioned with its natural inward curve, the discs are loaded evenly, and the jam is centred in the middle. Our spine and the discs within it can withstand considerable loads In this upright or neutral position. This includes holding bags full of shopping or carrying a heavy backpack. This neutral position is generally the position we get into when we stand and think tall.

If you have been to an Asian or African country, you may have seen locals gracefully carrying heavy produce and containers on their heads. They are always standing very straight; if they let their head or body bend forwards even slightly, they would either drop their load or create injuries that could threaten their livelihoods. This vision is true testament to the enormous strength of our spines if they are loaded in an upright or neutral position.

What goes wrong

Unfortunately, most of what we do in modern times is not in an upright or neutral spinal position, but rather a position in which we are bent in the middle. We sit at a desk, we sit in a car, we pick up a child’s toys, we lift groceries out of trolleys and we slump on the couch. When we bend, our lumbar spine loses its natural inward curve. The front part of the disc compresses. This causes the jelly in the centre of the disc to move.

Picture this––you raise the enticing jam donut to your mouth. It is full of sweet, warm jam, you take a big bite squashing the front half of the donut and compressing the space available for the jam. Where does the jam go? It squeezes out the back wall of the donut and runs down your hand . . .

This mouth-watering analogy is reminiscent of what happens to our discs when we bend a lot.

In reality, the jelly doesn’t burst out of the back of the disc straight away. Over time, the jelly pushes on the back wall of the disc so much that it creates little fissures or tears on the inside of the back wall of the disc. Then, each time you bend or sit, the jelly keeps pushing back into those fissures making them a bit bigger.

This process can be happening to your discs right now without you even being aware of it. The nerves (and therefore, your pain warning system) only supply sensation to the very outer layer of the disc wall, so internal damage can go undetected until . . .

You bend over to pick up a pen and BANG––sudden pain and spasm in your back. The cumulative disc load has finally caused the outside layer of the disc to become swollen and distended. You register a pain response via the nerves. For some people, the onset of pain is less dramatic (a small niggle that builds), but it can also escalate to a debilitating level.

Disc issues can become recurrent and ongoing. Once you have suffered once, you are ever vulnerable. Some people can correct these issues with rehab, others end up under the surgeon’s knife with a range of outcomes.

The management of these issues after they have occurred is not the focus of this post. We wish to address prevention. This prevention advice can still be relevant to you if you have already suffered a lumbar disc issue; however, this should be in consultation with your health professional.

Tune in next week to get your Back Pain Prevention Tool Kit!