What causes mechanical low back pain?
The lower back carries most of the body's load and takes most of the wear. Pain can come from the discs, the facet joints, the sacroiliac joints, or the surrounding muscle and ligament. Common causes include:
- Mechanical back pain — pain arising from the muscles, discs, facet joints, ligaments, or other spinal structures; often worse with certain movements or positions.
- Radicular pain (sciatica) — sharp, burning, or electric pain that travels from the lower back into the buttock and leg due to nerve irritation or compression.
- Neurogenic claudication — leg pain, heaviness, numbness, or weakness with standing or walking, commonly associated with lumbar spinal stenosis and relieved by sitting or leaning forward.
- Sacroiliac joint pain — pain arising around the SI joint, typically felt in the lower back or buttock and sometimes extending into the thigh.
- Myofascial pain — muscular pain associated with tightness, spasm, or tender areas in the muscles surrounding the spine.
- Vertebral pain — pain arising from the vertebral body, such as with an osteoporotic compression fracture.
- Inflammatory back pain — pain related to inflammatory disorders; classically associated with prolonged morning stiffness and improvement with activity.
- Referred pain — pain felt in the back but originating outside the spine, such as from the hip or certain abdominal/pelvic organs.
Symptoms
- Aching or stiffness across the low back, often worse in the morning or after sitting
- Pain that eases with movement and worsens with prolonged postures
- Episodes that come and go over months or years
- Discomfort that may spread into the buttock, but does not travel below the knee
- No numbness, tingling, or weakness in the leg or foot
Urgent
Seek urgent care for new loss of bowel or bladder control, numbness in the saddle area, or rapidly worsening leg weakness. Come in promptly for back pain following significant trauma, or accompanied by fever or unexplained weight loss.
How it is diagnosed
The examination establishes whether a nerve is involved, which is the question that matters most. Imaging is not routine for a first episode of uncomplicated back pain; it is used when symptoms persist, when the examination points somewhere specific, or when features suggest a cause other than degeneration.
Treatment
Most episodes settle. Early management focuses on staying active, physical therapy directed at core and hip strength, anti-inflammatory medication when safe, and practical adjustments to work and sleep. Recurrences are common and are not a sign that something has been missed. Where a specific joint is implicated, a diagnostic injection can both confirm and relieve.
When to see a spine surgeon
An evaluation is appropriate when pain persists despite appropriate non-operative care, when symptoms begin travelling down the leg, or when you want an honest read on what your imaging means. For back pain without nerve compression, surgery is usually not the answer.