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Low Back Pain


Peter J. Moley

, MD, Hospital for Special Surgery

Last full review/revision Nov 2020| Content last modified Nov 2020
Click here for the Professional Version
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Low back pain and neck pain are among the most common reasons for health care visits. The pain usually results from problems with the musculoskeletal system—most notably the spine, including the bones of the spine (back bones, or vertebrae), disks, and the muscles and ligaments that support it. Occasionally, low back pain results from a disorder that does not involve the musculoskeletal system.

Low back pain becomes more common as people age, affecting more than half of people over 60. It is very costly in terms of health care payments, disability payments, and missed work.

The spine (spinal column) consists of back bones (vertebrae). There are shock-absorbing disks between each of the vertebrae. The disks have a tough, outer layer of fibrocartilage and a soft, jelly-like interior called the nucleus. Each of the vertebrae have two joints behind the disks. The joints are called facet joints. The facets of one vertebral body rest on the facets of the one below it, forming a joint. The facet joints and thus the spine are stabilized by ligaments and muscles, which include the following:

  • Two iliopsoas muscles, which run along both sides of the spine

  • Two erector spinae muscles, which run along the length of the spine behind it

  • Many short paraspinal muscles, which run between the vertebrae

The abdominal muscles, which run from the bottom of the rib cage to the pelvis, also help stabilize the spine by supporting the abdominal contents. The muscles in the buttocks also help stabilize the spine. All together, these muscles are referred to as the core muscles.

Enclosed in the spine is the spinal cord. Along the length of the spinal cord, the spinal nerves emerge from the sides through spaces between the vertebrae to connect with nerves throughout the body. The part of the spinal nerve nearest the spinal cord is called the spinal nerve root. Because of their position, spinal nerve roots can be squeezed (compressed) when the spine is injured, resulting in pain.

The lower spine (lumbar spine) connects to the spine in the upper back (thoracic spine) above and to the pelvis through the (sacrum). The lumbar spine is flexible to allow turning, twisting and bending, and provides strength—for standing, walking, and lifting. Thus, the lower back is involved in almost all activities of daily living. Low back pain can limit many activities and reduce the quality of life.

Types of back pain

Common types of back pain include local, radiating, and referred pain.

Local pain occurs in a specific area of the lower back. It is the most common type of back pain. The cause is usually a small disk injury, joint arthritis, and rarely muscle sprains and strains. The pain may be constant and aching or, at times, intermittent and sharp. Sudden pain may be felt when an injury is the cause. Local pain can be aggravated or relieved by changes in position. The lower back may be sore when touched. Muscle spasms may occur.

Radiating pain is pain that travels from the lower back down the leg. The pain can be a dull ache or be sharp and intense. It typically involves only the side or back of the leg and may travel all the way to the foot or only to the knee. Radiating pain typically indicates compression of a nerve root caused by disorders such as a herniated disk, sciatica, osteoarthritis, or spinal stenosis. Coughing, sneezing, straining, or bending over while keeping the legs straight may trigger the pain. If there is pressure on the nerve root, the pain may be accompanied by muscle weakness in the leg, a pins-and-needles sensation, or even loss of sensation. Rarely, people lose bladder control (urinary incontinence) or bowel control (fecal incontinence).

Referred pain is felt in a different location from the actual cause of the pain. For example, some people who have a heart attack feel pain in their left arm. Referred pain from internal organs to the lower back tends to be deep and aching, and its exact location is hard to pinpoint. Typically, movement does not worsen it, unlike pain from a musculoskeletal disorder.

Causes of Low Back Pain

Most back pain is caused by disorders of the spine and the joints, muscles, ligaments, and nerve roots around it or the disks between vertebrae. Often, no single specific cause can be identified. Any painful disorder of the spine may cause reflex tightening (spasm) of muscles around the spine. This spasm may worsen the existing pain. Stress may worsen low back pain, but how it does so is unclear.

Occasionally, back pain is due to disorders outside the spine, such as cancer, gynecologic disorders (for example, premenstrual syndrome), disorders of the kidneys (for example, kidney stones) and urinary (for example, infections of the kidney, bladder, and prostate gland) and digestive tracts (for example, diverticulitis), and disorders of major arteries near the spine.

Common causes

Common causes of low back pain include

Injuries may occur during routine activities (for example, lifting, exercising, moving in an unexpected way) or result from trauma, such as a fall or car crash. Often no specific injured structures are identified with imaging tests, but doctors presume that some muscles and/or ligaments have been affected.

Osteoarthritis (degenerative arthritis) causes the cartilage between the facet joints to wear away and bone spurs (osteophytes) to form. This disorder is due in part to the wear and tear of years of use. People who repetitively stress one joint or a group of joints are more likely to develop osteoarthritis in that area. The disks between the vertebrae deteriorate, and the spaces between the vertebrae narrow, increasing the pressure on the facet joints, which become inflamed (arthritis) and form bone spurs in the openings for the nerve roots. With severe degeneration and loss of disc height the osteophytes in the opening can compress spinal nerve roots. All of these changes can cause low back pain as well as stiffness.

Vertebral compression (crush) fractures (fractures of spinal vertebrae) commonly develop when bone density decreases because of osteoporosis, which typically develops as people age. Vertebrae are particularly susceptible to the effects of osteoporosis. Vertebral compression fractures (which may cause sudden, severe back pain) can be accompanied by compression of spinal nerve roots (which may cause chronic back pain). However, most fractures due to osteoporosis occur in the upper and middle back and cause upper and middle rather than low back pain.

A ruptured or herniated disk can cause low back pain. A disk has a tough outer layer and a soft, jelly-like interior. If a disk is repeatedly overloaded by the vertebrae above and below it (as when bending forward, particularly when lifting a heavy object), the outer layer may tear (rupture), causing pain. The interior of the disk can squeeze through the tear, so that part of the interior bulges out (herniates). This bulge can compress, irritate, and even damage the spinal nerve root next to it, causing more pain and symptoms that are felt in one or both legs. A ruptured or herniated disk in the low back that affects nerves commonly causes sciatica. However, imaging studies such as magnetic resonance imaging (MRI) often show bulging disks in people who have no symptoms or problems.

Lumbar spinal stenosis is narrowing of the spinal canal, which runs through the center of the spine and contains the spinal cord and the bundle of nerves that extends downward from the bottom of the spinal cord in the lower back. It is a common cause of low back pain in older people. Spinal stenosis also develops in middle-aged people who were born with a narrow spinal canal. Spinal stenosis is caused by such disorders as osteoarthritis, spondylolisthesis, ankylosing spondylitis, and Paget disease of bone.

Spinal stenosis may cause sciatica as well as low back pain.

Spondylolisthesis is partial displacement of a vertebra in the lower back. One type usually occurs during adolescence or young adulthood (often in athletes) caused by an injury that fractures a part of the vertebra. If both sides of the vertebra are involved, the vertebra can then slip forward over the one below it. Spondylolisthesis can also occur in older adults but mainly as the result of a degenerative condition. People who develop spondylolisthesis as adults are at risk of developing lumbar spinal stenosis.

Fibromyalgia is a common cause of pain that affects many parts of the body, sometimes including the low back. This disorder causes chronic widespread (diffuse) pain in muscles and other soft tissues in areas outside the lower back. Fibromyalgia is also characterized by poor sleep and fatigue.

Did You Know...

  • Strengthening abdominal muscles, as well as back muscles, helps support the spine and prevent low back pain.

Less common causes

Less common causes of low back pain include

Evaluation of Low Back Pain

The doctor aims to identify any serious disorders. Because low back pain is often caused by several problems, diagnosing a single cause may not be possible. Doctors may only be able to tell that the cause is a musculoskeletal disorder and how serious it is likely to be.

Warning signs

In people with low back pain, certain symptoms and characteristics are cause for concern. They include

When to see a doctor

People should see a doctor immediately if they have fever or any of the warning signs that suggest nerve damage, an abdominal aortic aneurysm, a digestive disorder, or a urinary tract disorder. People with most other warning signs should see a doctor within a day. If pain is not severe and people have no warning signs other than pain for more than 6 weeks, their need to see a doctor is not as urgent.

What the doctor does

Doctors first ask questions about the person's symptoms and medical history. Doctors then do a physical examination. What they find during the history and physical examination often suggests a cause and the tests that may need to be done (see Table: Some Causes and Features of Low Back Pain).

Doctors ask questions about the pain:

  • What is the pain like?

  • How severe is it?

  • Where is it and where does it radiate to?

  • What relieves or worsens it (for example, changes in position or weight bearing)?

  • When and how did it start?

  • Are there other symptoms (such as numbness, weakness, retention of urine, or incontinence)?

Certain characteristics of the pain can give clues to possible causes:

  • Pain in an area that is tender to the touch and is worsened by changes in position or weight bearing is usually local pain.

  • Pain that radiates down the leg, such as sciatica, is usually caused by compression of a spinal nerve root.

  • Pain that is not affected by changes in position of the back and is not accompanied by tenderness may be referred pain.

  • Pain that is constant, severe, progressively worse, and unrelieved by rest, particularly if it keeps the person awake at night, can be a disk herniation but may indicate cancer or an infection.

The physical examination is focused on the spine and on evaluation of the nerves to the groin and legs to look for signs of nerve root compression. Signs of nerve root compression depend on which nerve roots are involved and include weakness of one of the muscle groups in a leg, abnormal reflexes (tested by tapping the tendons below the knee and behind the ankle), decreased sensation in an area of the leg, and, very rarely, retention of urine and incontinence of urine or stool (fecal incontinence).

Doctors may ask the person to move in certain ways to determine the type of pain. Doctors typically ask the person to bend forward and backward. They may have the person lie flat and then lift their leg without bending the knee to see if it brings on pain, which would suggest a herniated disc. Doctors may also check a person's abdomen for tenderness or a mass and the pulses, particularly in people over 55, who may have an aortic aneurysm. They may examine the prostate in men by doing a digital rectal examination and the internal reproductive organs in women by doing a pelvic examination.

With information about the pain, the person’s medical history, and results of a physical examination, doctors may be able to determine the possible cause.


Some Causes and Features of Low Back Pain


Common Features*


Common causes

Pain that

  • Often occurs on one or both sides of the spine

  • Worsens with movement and lessens with rest

  • Typically develops while lifting, bending, or twisting

A doctor's examination

Osteoarthritis, sometimes with compression of a spinal nerve root

Pain over a specific part of the spine, which sometimes

  • Is worsened by standing

  • Is relieved by sitting

  • Travels down a leg

  • Is accompanied by numbness and/or weakness

Usually in older people with pain and/or deformities in other joints


Sometimes MRI or CT (for osteoarthritis that is severe enough to cause nerve root pain)

Pain over a specific part of the spine, sometimes starting suddenly

Usually in people who are older or who have osteoporosis


Sometimes CT or MRI

A herniated disk, usually with compression of a spinal nerve root

Pain over a specific part of the spine that usually

  • Travels down a leg

  • Is accompanied by numbness and/or weakness

  • Is worsened by coughing, sneezing, straining, or leaning forward

A doctor's examination

Sometimes MRI

Rarely CT

Pain over a specific part of the spine in the lower back that

  • Is worsened by straightening the back (as when walking or leaning back)

  • Is relieved by leaning forward or sitting

  • May travel down one leg or both legs

Usually in older adults

A doctor's examination

Sometimes MRI

Spondylolisthesis, sometimes with compression of a spinal nerve root

Back pain that sometimes

  • In adolescents, is on one side of the spine, may travel down a leg, and may accompany a fracture

  • In adults, is over a specific part of the spine, travels down both legs, and involves tissue degeneration

  • Is accompanied by numbness and/or weakness

  • Is worsened by standing or leaning back

Often in adolescents associated with a fracture and in adults associated with degeneration (two different processes)


MRI or sometimes CT

Aching and stiffness in many areas of the body (not just the lower back)

Sore areas that are tender to the touch

Often poor sleep

Most common among young or middle-aged women

A doctor's examination

Less common causes

Ankylosing spondylitis (inflammation of the spine and large joints)

Stiffness, often worse immediately after awakening

Progressive loss of back flexibility, often causing the back to hunch forward

Sometimes a painful red eye and/or pain in other joints

Often in young men

X-rays or occasionally MRI

Blood tests

Numbness in the groin and around the anus


Pain in a strip of skin on either the right or left side of the body, but not both

Usually blisters develop on the painful strip of skin often after the pain starts

A doctor's examination


Progressively worsening pain, regardless of position or activity

Sometimes loss of appetite and/or weight

Usually x-rays



Progressively worsening, constant pain, regardless of position or activity

Sometimes fever and/or night sweats

Often in people who have had back surgery, who have an immune disorder, who take drugs that suppress the immune system, or who use IV drugs

Usually x-rays


Blood tests

* Features include symptoms and results of the doctor's examination. Features mentioned, including pain, are typical but not always present.

† If pain resolves without treatment and no warning signs are present, testing may not be necessary.

CT = computed tomography; IV = intravenous; MRI = magnetic resonance imaging.


Usually, no tests are needed because most back pain results from osteoarthritis, strains and sprains, or other minor musculoskeletal disorders and resolves within 6 weeks. Imaging tests are often needed if

  • Another cause is suspected

  • Warning signs are present

  • Back pain persists

People who did not respond to initial treatment or those whose symptoms have worsened or changed may also undergo testing.

X-rays of the lower back show only the bones. They can help detect degenerative changes due to osteoarthritis, vertebral compression fractures, spondylolisthesis, and ankylosing spondylitis. However, magnetic resonance imaging (MRI) or computed tomography (CT) provides clearer images of bones and, particularly MRI, can show soft tissues (including disks and some nerves). MRI or CT is usually necessary when doctors are checking for disorders that cause subtle changes in bone and disorders of soft tissue. For example, MRI or CT can confirm or exclude the diagnosis of a herniated disk, spinal stenosis, cancer, and usually infection. These tests can also indicate whether nerves are being compressed.

If compression of the spinal cord is suspected, MRI is done immediately. Rarely, when results of MRI are unclear, myelography with CT is required. Rarely, if cancer or infection is suspected, removal of tissue (biopsy) is necessary. Occasionally, electromyography and nerve conduction studies are done to confirm the presence, location, and sometimes duration and severity of nerve root compression.

Prevention of Low Back Pain

People can reduce their risk of developing low back pain by doing the following:

  • Exercising

  • Strengthening and stretching muscles

  • Maintaining a healthy weight

  • Maintaining good posture

  • Using proper lifting techniques

The most effective way to prevent low back pain is to exercise regularly. Aerobic exercise and specific muscle-strengthening and stretching exercises can help.

Aerobic exercise, such as swimming and walking, improves general fitness and generally strengthens muscles.

Specific exercises to strengthen and stretch the muscles in the abdomen, buttocks, and back (the core muscles) can help stabilize the spine and decrease strain on the disks that cushion the spine and the ligaments that hold it in place.

Muscle-strengthening exercises include pelvic tilts and abdominal curls. Stretching exercises include the knee-to-chest stretch. Stretching exercises can increase back pain in some people and therefore should be done carefully. As a general rule, any exercise that causes or increases back pain should be stopped. Exercises should be repeated until the muscles feel mildly but not completely fatigued. Breathing during each exercise is important. People who have back pain should consult a doctor before beginning to exercise.

Exercises to Prevent Low Back Pain

Pelvic Tilts

Lie on the back with the knees bent, the heels on the floor, and the weight on the heels. Press the small of the back against the floor, contract the buttocks (raising them about half an inch [1 cm] from the floor), and contract the abdominal muscles. Hold this position for a count of 10. Repeat 20 times.

Exercises to Prevent Low Back Pain

Abdominal Curls

Lie on the back with the knees bent and feet on the floor. Place the hands across the chest. Contract the abdominal muscles, slowly raising the shoulders about 10 inches (25 cm) from the floor while keeping the head back (the chin should not touch the chest). Then release the abdominal muscles, slowly lowering the shoulders. Do 3 sets of 10.

Exercises to Prevent Low Back Pain

Knee-to-Chest Stretch

Lie flat on the back. Place both hands behind one knee and bring it to the chest. Hold for a count of 10. Slowly lower that leg and repeat with the other leg. Do this exercise 10 times.

Exercises to Prevent Low Back Pain

Exercise can also help people maintain a desirable weight. Weight-bearing exercise can help people maintain bone density. Thus, exercise may reduce the risk of developing two conditions that can lead to low back pain—obesity and osteoporosis.

Maintaining good posture when standing and sitting reduces stress on the back. Slouching should be avoided. Chair seats can be adjusted to a height that allows the feet to be flat on the floor, with the knees bent up slightly and the lower back flat against the back of the chair. If a chair does not support the lower back, a pillow can be used behind the lower back. Sitting with the feet on the floor rather than with the legs crossed is advised. People should avoid standing or sitting for long periods. If prolonged standing or sitting is unavoidable, changing positions frequently may reduce stress on the back.

Learning to lift correctly helps prevent back injury. The hips should be aligned with the shoulders (that is, not rotated to one side or the other). People should not bend over with their legs nearly straight and reach out with their arms to pick up an object. Instead, they should bend at the hips and knees. Bending this way keeps the back straighter and brings the arms down to the object with the elbows at the side. Then, keeping the object close to the body, they lift the object by straightening their legs. This way, the legs, not the back, lift the object. Lifting an object over the head or twisting while lifting increases the risk of back injury.

Treatment of Low Back Pain

If a specific cause can be diagnosed, that disorder is treated. For example, antibiotics are used to treat a prostate infection. However, there is no specific treatment for musculoskeletal pain due to sprains or strains nor for many other musculoskeletal causes. But many general measures can help. Usually, these general measures are also used when a spinal nerve root is compressed.

General measures for back pain

Measures include

  • Modifying activities

  • Taking drugs that relieve pain

  • Applying heat or cold to the painful area

  • Light exercise as tolerated

For low back pain that has recently developed, treatment begins with avoiding activities that stress the spine and cause pain—such as lifting heavy objects and bending. Bed rest does not hasten the resolution of the pain, and most experts recommend continued light activity. Bed rest, if required to relieve severe pain, should last no more than 1 or 2 days. Longer bed rest weakens the core muscles and increases stiffness, thus worsening back pain and prolonging recovery. Spinal corsets and traction are not helpful. Traction may delay recovery.

Acetaminophen is usually recommended for pain relief unless inflammation is present. Over-the-counter or prescription nonsteroidal anti-inflammatory drugs (NSAIDs) can relieve pain and reduce inflammation. If acetaminophen or NSAIDs do not provide sufficient pain relief, opioid analgesics are occasionally prescribed but, if so, should be used only for a short duration because long-term use of opioid analgesics can actually increase sensitivity to pain, cause side effects, and risk the development of a substance use disorder.

Muscle relaxants, such as carisoprodol, cyclobenzaprine, diazepam, metaxalone, or methocarbamol, are sometimes given to relieve muscle spasms, but their usefulness is controversial. These drugs are not recommended for older people, who are more likely to have side effects such as drowsiness and confusion. Doctors try not to prescribe muscle relaxants unless people have visible and palpable muscle spasms. If prescribed, muscle relaxants should be used for no more than 72 hours. Doctors sometimes tell people to take them only at bedtime.

Application of heat or cold may help (see Treatment of Pain and Inflammation). Cold is usually preferred to heat during the first 2 days after an injury. Ice and cold packs should not be applied directly to the skin. An ice pack should be enclosed (for example, in plastic) and placed over a towel or cloth. The ice is removed after 20 minutes, then reapplied for 20 minutes over a period of 60 to 90 minutes. This process can be repeated several times during the first 24 hours. Heat, using a heating pad, can be applied for the same periods of time. Because the skin on the back may be insensitive to heat, heating pads must be used cautiously to prevent burns. People should not use a heating pad at bedtime to avoid the risk of falling asleep with the pad still on their back.

Massage may provide some temporary relief of low back pain. Some studies suggest that acupuncture may have similar benefits, but others suggest little or no benefit. Spinal manipulation, done by chiropractors or some other doctors (such as osteopathic doctors), may also provide relief when combined with an exercise program. However, spinal manipulation may increase the risk of further injury and should be avoided in people who have inflammatory arthritis, neck problems that cause instability of neck vertebrae, or a herniated disk.

After the pain has subsided, light activity, as recommended by a doctor or physical therapist, can speed healing and recovery. In some cases, a course of treatment with a physical therapist can help. Specific exercises to strengthen and stretch the back and to strengthen core muscles are usually recommended to help prevent low back pain from becoming chronic or recurring.

Sleeping in a comfortable position on a medium mattress is recommended. People who sleep on their back can place a pillow under their knees. People who sleep on their side should use a pillow to support their head in a neutral position (not tilted down toward the bed or up toward the ceiling). They should place another pillow between their knees with their hips and knees bent slightly if that relieves their back pain. People can continue to sleep on their stomach if they are comfortable doing so.

Other preventive measures (maintaining good posture, lifting correctly) should be continued or started. In response to these measures, most episodes of back pain resolve in several days to 2 weeks. Regardless of treatment, 80 to 90% of such episodes resolve within 6 weeks.

Treatment of chronic back pain

Additional measures are needed for chronic low back pain. Aerobic exercise may help, and weight reduction, if necessary, is advised. If analgesics are ineffective, other treatments can be considered.

Transcutaneous electrical nerve stimulation (TENS) may be used. The TENS device produces a gentle tingling sensation by generating a low oscillating current. This current can block transmission of some pain sensation from the spinal cord to the brain. The current can be applied to the painful area several times a day for 20 minutes to several hours at a time, depending on the severity of the pain.

Sometimes a corticosteroid (such as dexamethasone or methylprednisolone) plus a local anesthetic (such as lidocaine) can be periodically injected into facet joints in the spine or the epidural space—between the spine and the outer layer of tissue covering the spinal cord. The epidural injections may be more effective for sciatica caused by a herniated disk than for lumbar spinal stenosis. However, it is not clear that they produce a long-term benefit. They are usually effective only for several days to weeks. Their main use is to relieve pain enough that an exercise program, which can provide long-term pain relief, can be started.

Surgery for back pain

If a herniated disk is causing relentless or chronic sciatica, weakness, loss of sensation, or loss of bladder and bowel control, surgical removal of the bulging part of the disk (diskectomy) and sometimes part of the vertebra (laminectomy) may be necessary.

For severe spinal stenosis, a large part of the back of the vertebra (the lamina) may be surgically removed to widen the spinal canal (lumbar laminectomy). A general anesthetic is usually required. The hospital stay is usually 4 or 5 days. People may need 3 to 4 months before they can resume all of their activities. About two thirds of people have a good or full recovery. For most of the rest, such surgery may prevent pain and keep other symptoms from worsening.

When the spine is unstable (as may result from a severe herniated disk, spondylolisthesis, or after laminectomy for spinal stenosis), surgery can be done to fuse vertebrae together (called lumbar spinal fusion). However, fusion decreases mobility and may put additional stress on the rest of the spine and cause further problems.

Low Back Pain: Surgery

Vertebral compression fractures

Vertebral compression fractures are quite common among women over 50 years of age. They can be treated conservatively with nonsurgical options such as braces, pain relievers, and possibly calcitonin nasal spray, which does not help bone healing but may decrease pain.

If pain is not adequately controlled, two surgical options are available:

  • Vertebroplasty: A cement mixture is injected into the fractured bone.

  • Kyphoplasty: A balloon is inserted into the fractured bone to create space. The balloon is then filled with cement.

However, recent studies have shown that, in the long term, these surgical procedures are no more effective than nonsurgical options.

Key Points about Low Back Pain

  • Low back pain is very common and usually caused by a musculoskeletal disorder of the spine plus other factors, such as fatigue, obesity, and lack of exercise.

  • In young people, low back pain is rarely serious, and testing is usually unnecessary unless symptoms persist for weeks.

  • People who have warning signs or who are over age 55 should see a doctor without delay.

  • Strengthening abdominal and back muscles with specific exercises can help prevent the most common types of low back pain.

  • For most low back pain, avoiding activities that stress the back, taking pain relievers, and sometimes applying ice or heat are sufficient treatment.

  • Prolonged bed rest and traction can delay recovery.

  • In severe cases, for example, when people have abnormal sensation and weakness in the legs, surgery may be needed.

  • Vertebral compression fractures can be treated conservatively (with bracing, pain relievers, and calcitonin nasal spray) or occasionally more aggressively with surgery.

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