Your back is made up of 30 bones stacked in a column surrounded by muscles and ligaments. It allows you to stand, walk, bend, sit and twist. It connects other parts of your skeleton and supports your spinal cord and nerve roots. Nearly every movement you make involves your back in some manner. This constant movement and support mean that your back is susceptible to strain and stress.
About 80% of adults in the U.S. will experience low back pain at some point. Not all back pain is the same and symptoms can vary widely, ranging from intense, shooting or pinching pain to a dull, ongoing ache.
Occasionally, a person with back pain can pinpoint the exact time it started, such as when trying to lift a heavy object or after a fall. More commonly, no specific trigger or event led to the pain.
Understanding the causes of back pain, along with the symptoms, can help you and your health care team determine the best treatment options for you.
What causes back pain?
Here are the most common causes of back pain.
Muscle or ligament strain
Strains are usually caused by a single event, such as using poor body mechanics to lift a heavy object. Carrying more weight and certain repetitive motions also can strain muscles and spinal ligaments in your back.
Strains feel like a sudden stabbing, localized pain. This pain worsens when you contract the muscle or twist. Redness, swelling and bruising can occur. The pain can be intense and significantly affect daily activities. Occasionally, people say that they have “thrown out” their backs. In most cases, they have a muscle or ligament strain.
Disks act as cushions between the bones, or vertebrae, in your spine. The material inside a disk can bulge and press on a nerve.
It is possible and fairly common to have a bulging disk without pain. Pain from a bulging disk usually occurs in the low back and radiates into the hips, buttocks or legs. It is often worse with activity and feels better when resting.
A herniated disk results when a tear in the tough outer layer of the disk allows some of the inner disk material to protrude outward. Herniated disks also are called ruptured disks or slipped disks, although the whole disk does not rupture or slip.
Many people have no pain from a herniated disk. But compared with a bulging disk, a herniated disk is more likely to cause pain because it protrudes farther and is more likely to irritate nerve roots. Depending on where the herniated disk is, it can result in pain, numbness or weakness in one or both legs. They usually affect only one side of the body.
Sciatica is named after the sciatic nerve, which is the largest nerve in your body. It most commonly occurs when a herniated disk, bone spur on the spine or spinal stenosis compresses part of the nerve. This causes inflammation, pain and often some numbness in the affected leg.
Sciatica is a sharp, shooting pain that runs from your low back down the side or back of your leg. Typically, sciatica affects only one side of your body. Although the pain associated with sciatica can be severe, most cases resolve with nonoperative treatments in a few weeks.
Low back pain often is caused by osteoarthritis, the most common type of arthritis. Arthritis can lead to a narrowing of the space around the spinal cord or nerve roots, a condition called spinal stenosis. It occurs most often in the low back and neck. When this occurs in the low back, the most common symptoms are pain in both legs, tingling, numbness and sometimes muscle weakness. Symptoms are usually brought on by standing for a long time or walking longer distances.
Degenerative disk disease
As you age, the disks between your vertebrae begin to shrink and lose their softer qualities. This narrows the space between the vertebrae and can make your spine less flexible.
Degenerative disk disease does not always cause symptoms. If it does, symptoms vary widely in nature and severity. Generally, pain comes and goes over a long time. It may feel better when you change positions or walk, and worsen when you sit, bend or twist.
Spondylosis is a general term for age-related wear and tear on the bones in your spine. As disks dehydrate and shrink, bone spurs can develop where your vertebrae meet.
Bone spurs are common. More than 85% of people over age 60 are affected by them. Most bone spurs cause no symptoms or pain. You might not know you have bone spurs until revealed on imaging of your spine.
Back pain can occur if your spine curves abnormally or if the bones are not stacked directly on top of each other (a “slipped” vertebral body). Abnormal curves or slipped vertebral bodies can sometimes contribute to back pain.
When to schedule an appointment
Most low back pain — even when severe — goes away on its own in six to eight weeks with self-care, such as resting from heavy lifting, applying heat or ice, using over-the-counter pain medications and stretching. Physical therapy can provide tremendous relief from back and limb pain, and oftentimes people do not need additional imaging or evaluation with these measures.
Talk with your health care provider if your back pain occurs after a fall or another injury, or you have a history of cancer.
In addition, schedule an appointment if you have any of these back pain symptoms:
- Constant or intense pain, especially at night or when you lie down.
- Spreads down one or both legs.
- Causes weakness, numbness or tingling in one or both legs.
- Occurs with a fever, swelling or redness on your back.
- Occurs with unintended weight loss.
- Occurs with new bowel or bladder control problems.