Back pain is a very common problem for many people. Most will just endure it, not understanding what the problem is and not knowing what they can do from day to day to help. This is the beginning of a series of blogs to help you know a bit more about why you may get back pain and what you can do about it.
When considering how to look after your back, it is important to look at the anatomy of the spine and what and why things go wrong. This will give you a good understanding of how it all works, so you know why you may get back pain when doing or not doing certain activities.
The first thing to understand is the spine and its anatomy. The spine is made up of blocks of bone stacked one on the other forming a column. These blocks are ‘the vertebrae’ and are classified into 4 groups – the cervical (neck), the thoracic (mid-back), the lumbar (lower back) and the sacrum. Sandwiched between each vertebra is a disc. The discs are soft tissue and act as the suspension pads of the spine, absorbing the impact and pressures experienced by our bodies as we move around from day to day. Ultimately, the aim of the vertebra and discs is to protect the brain and spinal cord which distributes nerves to the limbs, thorax and head via the vertebral column. The discs are subject to different pressures depending on what we are doing. Essentially, the discs experience the least amount of pressure when we are lying down – simply because we are not upright with the weight of the body bearing down on the discs. They also are happiest when we maintain the ‘natural curves’ of our spine – the cervical and lumbar spine (neck and lower back) have an inward curve and the thoracic or mid- back curves outwards. When we bend forward the lumbar spine changes its position. The pressure within each of the lumbar disc increases. This is a normal phenomenon, and our bodies are designed to do this.
So, what goes wrong?
Problems occur when the discs undergo pressure for sustained and prolonged periods of time. The integrity of the disc tissue can wear down over time and the disc can bulge, putting pressure on the structures around the vertebrae and disc – in particular the nerves and facet joints. In reality, the disc experiences micro tears in the disc wall which over time build to become a bulge as the fluid inside the disc seeps through the small tears to press on the nerves. This can translate into pain either in the back or as referred pain elsewhere in the leg or arm as the disc bulge presses on to a nerve root that travels down the limb. This disc bulge can also occur suddenly with a rapid and unexpected increase in pressure that will pop the disc wall. This is often the result of lifting a very heavy load or repeated bending forward with the disc giving way suddenly.
So, essentially, there are 3 main ways that disc problems can lead to back pain including:
- Sustained and prolonged pressure on the discs. An activity that I commonly see that can cause this problem is slumped forward sitting at the computer or driving. This position involves loss of the neck and lower back curves and, if this goes on for hours, can lead to overload on the discs resulting in pain.
- Repeated forward bending – such as continually picking things up off the ground.
- Picking up heavy objects with a bent lower back
Back pain from disc issues is often recurring. Once you have experienced this sort of back pain you are susceptible to recurrent episodes. However, this can be managed with appropriate rehabilitation including education and strengthening.
This sets the scene for the next few weeks as we talk about back care. There are other structures that cause back pain apart from the discs (which I will go into over the coming weeks), however the main driver of back pain tends to be the vertebral discs.
When I have someone come to see me with back pain, I will often ask them to count how many times they bend forward for one whole day. This includes picking things up off the ground such as shoes, a child or two, the family pet, dirty clothes, unloading the dishwasher, milk from the fridge etc. This is worth trying – you may be surprised how often you repeatedly bend forward and inadvertently load up the discs in the lower back.