What causes back pain & sciatica?
Back pain almost never has a single culprit. It builds out of how you sit, how you lift, how well your hips move, and how the discs and joints of your spine have been sharing load for years. Sciatica is not a separate disease either. It is the name for what you feel when a nerve running from the low back into the leg gets irritated somewhere along its path. Finding the actual driver is the difference between quieting the pain for a weekend and ending it.
The disc sits between two vertebrae and its softer center can push out through the tougher outer wall. When that bulge sits against a nerve root, the pain stops being local and starts running into the buttock, the hamstring or the calf, sometimes with pins and needles alongside it. Sitting, bending forward and coughing usually make it louder. Discs respond well to directional movement and graded loading, and most never require an injection or an operation.
Sciatica describes a symptom, not a diagnosis. The nerve can be irritated at the disc, squeezed where the spinal canal has narrowed, or compressed as it passes under a tight, overworked glute. All three feel similar to you and are treated completely differently, which is why guessing gets expensive. Nerve tension testing, strength testing and how your symptoms behave with movement tell us which one you have on the first visit.
The lumbar spine is designed to be supported by the muscles wrapping it and by hips that move freely. When the deep trunk muscles switch off and the hips get stiff, the low back absorbs forces that were never meant to land there. It shows up as a spine that feels fragile: fine for a while, then suddenly not. Rebuilding coordinated strength through the trunk and hips takes that load back off.
It is rarely one bad lift. It is countless hours folded into a chair, a car seat and a couch, with the hip flexors shortening and the postural muscles going quiet. Sustained flexion loads the discs steadily and gives the tissue no variety at all. Changing how often you move, not just how you sit, is usually a bigger lever than any single stretch you have been handed.
Discs lose height and water content as the years pass, and the facet joints work harder for it. Scans full of degeneration belong to plenty of people with no pain at all, which is the most useful thing to know about your imaging report. Degeneration is not the reason you hurt. A spine that is stiff, weak and unaccustomed to load is, and all of that is trainable.
Sometimes there is a clear moment: a heavy box with a rounded back, an awkward twist, a step off a curb that jarred the whole spine. The tissue was asked for more than it could tolerate and it protested. Acute strains hurt intensely and settle faster with early, controlled movement than with days of bed rest. The longer aim is a spine that can take that same demand next time it arrives.
