Low Back Pain

What It Is

The lower back, or lumbar region, supports much of the body's weight and allows bending and twisting. It is made up of vertebrae (bones), discs that cushion the bones, joints, muscles, ligaments, and nerves.

Low back pain is often grouped by how long it lasts. Acute pain lasts less than about 4 weeks, subacute pain lasts 4 to 12 weeks, and chronic pain lasts 12 weeks or longer.

In most people, low back pain comes from the muscles, ligaments, discs, or joints and gets better over time. A small number of cases are linked to serious conditions, such as infection, fracture, cancer, or nerve compression, which need prompt evaluation.

Common Terminology

Lumbar spine

The five vertebrae in the lower back.

Sciatica

Pain that travels from the lower back down the back of the leg, caused by irritation of the sciatic nerve or its roots.

Herniated disc

A disc between vertebrae whose soft inner material pushes out and may press on nearby nerves.

Spinal stenosis

Narrowing of the spaces in the spine, which can put pressure on nerves.

Cauda equina syndrome

A rare, serious condition in which nerves at the bottom of the spinal cord are compressed; it is treated as an emergency.

Nonspecific low back pain

Back pain without a clearly identified specific cause, which is the most common type.

Common Causes and Associations

Low back pain is commonly associated with the following. This is general education, not a way to identify the cause in any particular case.

• Strained muscles or ligaments, often from lifting, twisting, or sudden movements.
• Age-related wear of the discs and joints of the spine.
• Herniated or bulging discs, which may irritate nearby nerves.
• Spinal stenosis, more common in older adults.
• Factors such as inactivity, excess body weight, poor physical conditioning, and smoking.
• Less commonly, fractures (for example, related to osteoporosis), infections, kidney problems, or cancer.

Symptoms and Features

This is a general description of how this symptom is often described, not a diagnostic checklist.

• A dull ache, stiffness, or muscle spasm in the lower back.
• Sharp pain that may get worse with bending, lifting, sitting, or standing for long periods.
• Pain, tingling, or numbness that travels down one leg, which is commonly described in sciatica.
• Reduced flexibility or difficulty standing up straight.
• Pain that often improves with gentle movement and changes in position.

Tests and Evaluation

Evaluation usually starts with a history and physical exam. Many cases do not need tests.

• Questions about how the pain began, its pattern, and any warning signs.
• A physical exam checking movement, posture, and tender areas.
• A neurological exam testing strength, reflexes, and sensation in the legs.
• Imaging such as X-ray, MRI, or CT scan, generally reserved for warning signs or pain that does not improve as expected.
• Blood tests in some cases, for example when infection or inflammation is suspected.

Treatment Overview

Treatment depends on the cause and duration, and is guided by a healthcare professional.

• Staying as active as comfortable and returning to normal activities gradually is commonly recommended.
• Heat, over-the-counter pain relievers, and short periods of rest are often used for comfort.
• Physical therapy and specific exercises can help strengthen the back and core muscles.
• Other approaches sometimes used include massage, spinal manipulation, acupuncture, and yoga.
• For some chronic or nerve-related cases, injections or surgery may be considered by specialists.

When Professional Care May Be Discussed

Health organizations generally describe these situations as reasons for urgent or prompt evaluation.

• Back pain with new loss of bladder or bowel control, or numbness in the groin or inner thighs, is generally treated as a medical emergency; in the US, people are advised to call 911 or seek emergency care.
• Back pain with weakness in the legs that is getting worse is generally evaluated urgently.
• Back pain after a significant fall or injury is commonly evaluated promptly.
• Back pain with fever, unexplained weight loss, or a history of cancer is commonly evaluated promptly.
• Pain that does not improve after several weeks or is severe at night is commonly discussed with a healthcare professional.

Questions to Ask a Healthcare Professional

General questions people often find useful to bring to an appointment:

• What are the most common causes of low back pain?
• Why is imaging often not needed for new back pain?
• What is sciatica and how is it related to back pain?
• How can physical therapy help low back pain?
• Which back pain warning signs are considered emergencies?
• What general steps are linked to lowering the risk of back pain returning?

Sources

This guide was written in plain language from the following authoritative references.

1. Back Pain — MedlinePlus (U.S. National Library of Medicine)
2. Back pain — NHS (UK National Health Service)
3. Sciatica — NHS (UK National Health Service)

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