Many conditions can cause leg pain and foot pain. Commonly, the main cause of the symptoms has its origin in the lower back, which is where the nerves branch out from the spine to provide function to the muscles in the leg, ankle, and foot.

See Getting an Accurate Back Pain Diagnosis

Low back conditions that are common causes of leg pain and/or foot pain—and associated neurological symptoms such as numbness or foot drop—are outlined below.

Lumbar Degenerative Disc Disease

As we age, our intervertebral discs dehydrate (lose water), degenerate, lose their flexibility and allow small movements, which can cause pain from the disc that may radiate down the leg. While the primary symptom of lumbar degenerative disc disease is usually low back pain, leg pain and foot pain are also common symptoms.

See Lumbar Degenerative Disc Disease (DDD)

When lumbar degenerative disc disease presents with leg pain and/or foot pain, this is called "referred pain." Another common example of referred pain includes neck/arm or shoulder pain caused by heart attacks. The brain cannot always distinguish exactly where the pain source is, and so feels pain more vaguely in multiple areas. Referred pain is typically dull, achy, and poorly localized.

See Low Back Pain with Referred Pain

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Leg pain from degenerative disc disease can also result if the nerve root is compressed. This happens because as the disc degenerates it shrinks and moves, and as a result, there is not as much room for the nerve roots. This is also known as foraminal stenosis. Leg pain from a compressed and inflamed nerve root is typically shooting and electric.

See Exercise for Sciatica from Degenerative Disc Disease

Lumbar Herniated Disc

A disc herniation tends to put pressure on the weakest spot in a disc, an area that happens to be right under the nerve root. This results in pain that can radiate all the way down the sciatic nerve throughout the patient’s leg and into the foot. Depending on the nerve root affected, other nerves (beside the sciatic nerve) may also be involved.

See Sciatic Nerve and Sciatica

Symptoms of a lumbar herniated disc tend to vary depending upon where the disc herniation occurs. There is a wide range of non-surgical treatments that can alleviate leg pain for the majority of types of herniated discs. For severe pain or disability, a microdiscectomy (or micro-decompression) surgery to remove a portion of the disc can relieve the pressure on the nerve, which allows the inflammation to subside as the pinched nerve heals.

Read more: Treatment Options for a Lumbar Herniated Disc and Exercise for Sciatica from a Herniated Disc

Lumbar Spinal Stenosis

Spinal stenosis in the low back occurs when the spinal nerve roots are compressed or choked, usually by enlarged facet joints located in the back of the spinal column. Spinal stenosis usually, but not always, occurs in elderly patients as the facet joints enlarge due to degeneration of the spine that tends to occur with age.

See What is Spinal Stenosis?

The narrowing can be confirmed with an MRI scan. The symptoms of spinal stenosis are often referred to as sciatica: leg pain, radiating pain, tingling, leg weakness and/or numbness. Doctors usually use the words radiculopathy or radiculitis to describe the same symptoms.

See Lumbar Spinal Stenosis: A Definitive Guide

The leg pain from stenosis tends to develop gradually over time (mirroring the cumulative narrowing process taking place in the spine as the facet joints enlarge). Spinal stenosis symptoms tend to improve when the patient leans forward, a position that has the effect of opening up the back of the spinal column, taking pressure off the spinal nerve roots.

See Exercise for Sciatica from Spinal Stenosis

Spondylolisthesis

Spondylolisthesis occurs when a vertebra in the spine slips forward over the next, lower vertebra, compromising the natural structure of the spine segment as well as its stability and flexibility.

See Spondylolysis and Spondylolisthesis

The resulting instability can lead to a nerve being pinched and/or inflamed, which causes leg pain. Many patients find pain relief through a combination of physical therapy and rest during episodes of acute pain, although significant instability and persistent pain may be treated with fusion surgery. Targeted injections may also be beneficial at times to help alleviate the inflammation from around an inflamed nerve root.

See Exercise for Sciatica from Isthmic Spondylolisthesis

Sciatica Is a Symptom of Low Back Problems

All symptoms of leg pain caused by the conditions listed above are often referred to as sciatica. This is because the pain often radiates along the sciatic nerve, which originates with certain nerve roots in the low back and runs through the back of each leg into the foot.

Sciatica can present as either a constant pain (usually in the buttock) or a shooting pain through the leg. See:

In addition, two other common conditions, piriformis syndrome and sacroiliac joint dysfunction, can also cause leg pain and sciatica-type symptoms.

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Written by Grant Cooper, MD