The Lower Back (Lumbar Spine)
The lower back is known as the Lumbar spine. It is made up of five spinal segments. You may hear your doctor or therapist talk about L1, L2, L3… These terms describe the level of the lumbar spine that is affected.
The lumbar spine has joints called facet joints on either side, as seen on the picture. The picture shows facet joints from the upper spine and the lumbar spine, as you can see they are shaped differently. This is key to their function. The lumbar spine does not like too much rotation, as you can see the segments would clatter if there was too much rotation. In comparison to the upper back which has a much smoother slide in rotation. These facet joints can be one of the reasons why your back is in pain or discomfort. They can be irritated and this is termed as facet joint irritation, it is usually very painful on leaning back motions.
The other structure you see in the diagram are the discs. A common complaint you may have heard of is ‘slipped discs’. Our discs are made up of a toothpaste type fluid covered by a fibrous sheath. Their main role is to help with shock absorption when we walk, run, jump and do all the things we love to do. If there is too much pressure on the lower back, the toothpaste fluid may push out (as in diagram) causing a bulge or a prolapse. This is usually painful on sitting, leaning forward and coughing or sneezing. As we age the disc can also begin to dehydrate and become thinner, providing less shock absorption. We commonly know this as degeneration or simply wear and tear.
The nerves that exit from this area of the lower back supply our lower limbs giving us the ability to feel and move. These nerves can get trapped due to a disc bulge and other reasons. If they do, you usually will feel symptoms of pins and needles, numbness or weakness of your lower limb. Depending on where your injury has occurred will determine where you feel this discomfort. Commonly the lower segments are involved and trap the sciatic nerve causing ‘sciatica’. Sciatica is a term to denote a trapped sciatic nerve and this can happen for many reasons. It is important that you see a professional so that they can assess you to determine why it is being trapped.
Lastly, of course we have muscles and ligaments of the lower back. Muscles are very connected and linked in many different ways. They are reactors to joint movement and if they are injured or strained we need to do detective work to figure out way. To differentiate this from the problems described above, muscular pain is usually relieved by hot water, gentle stretching and rest.