The lumbar spine is the lower section of the spine, made up of five large vertebrae between the ribcage and the pelvis, that bears the majority of the body's weight and enables bending, twisting, and extension of the trunk.
What your lumbar spine does — including the role of L5 — and why it's so commonly affected by pain
Your lumbar spine sits at the base of your torso, and it carries more load than any other region of the spine — supporting the weight of your upper body during every movement, absorbing force during walking and running, and transferring load between the trunk and the lower limbs.
The five lumbar vertebrae are large and robust, but the intervertebral discs between them, the facet joints at the back of each level, and the nerves that exit the spine here are all structures that can be irritated by poor mechanics, prolonged posture, sudden injury, or gradual wear over time. Low back pain is the most common musculoskeletal complaint worldwide, and the lumbar spine is the source in the vast majority of cases — from acute muscle strain to disc herniation at levels like L4-L5 or L5-S1, facet joint irritation, and spinal stenosis.
Why lumbar spine pain is so often recurring
A single episode of low back pain frequently resolves on its own, but without addressing the underlying movement patterns, muscle imbalances, and loading habits that contributed to it, the same problem tends to return. That cycle — pain, rest, temporary relief, recurrence — is the most common pattern in untreated lumbar spine conditions.
Why imaging doesn't always point to the answer
MRI findings in the lumbar spine are extremely common in adults with no back pain at all — disc bulges, degenerative changes, and facet arthritis are present in a large proportion of people who've never had a back complaint. The scan tells you what's structurally present, not necessarily what's generating your symptoms. A physical therapist can help you understand the relationship between what's on the scan and what you're actually feeling.
How Sword Health can help
A physical therapist can assess what's driving your lumbar spine pain — whether it's your first episode or a long-standing pattern — and build a plan that addresses both the immediate symptoms and the underlying mechanics. Sword makes that care available from home, without the wait.
About the author
Carolina Moreira
Medical Director of Clinical Development at Sword Health
