The term sciatica refers to sciatic nerve symptoms that originate in the lower spine, radiate deep into the buttock, and travel down into the leg and foot. Sciatica is so common that many use the term in an overly broad manner, incorrectly applying it to other types of lower back and leg problems.
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Sciatica Is the Symptom of an Underlying Condition
The term sciatica refers to a set of symptoms caused by an underlying medical condition and it’s not an actual medical diagnosis. 1 Cook CE, Taylor J, Wright A, Milosavljevic S, Goode A, Whitford M. Risk Factors for First Time Incidence Sciatica: A Systematic Review. Physiotherapy Research International. 2013;19(2):65-78. doi:10.1002/pri.1572. The symptoms occur when a nerve root in the lower spine is irritated or compressed by a chemical or mechanical source.
The sciatic nerve is formed by the union of 5 nerve roots (L4 to S3) in the lumbar and sacral spine. 2 Giuffre BA, Jeanmonod R. Anatomy, Sciatic Nerve. [Updated 2018 Dec 16]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2019 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK482431/. Irritation or compression of any of these nerve roots (also called radiculopathy) can cause pain, numbness, and/or weakness along the entire distribution of the nerve. Nerve root irritation is most common at the L4, L5, and/or S1 level of the spine. 3 Hernández C.P., Sanchez N., Navarro-Siguero A., Saldaña M.T. (2013) What is Sciatica and Radicular Pain?. In: Laroche F., Perrot S. (eds) Managing Sciatica and Radicular Pain in Primary Care Practice. Springer Healthcare, Tarporley. https://doi.org/10.1007/978-1-907673-56-6_1.
Common causes of sciatica are described below. 4 Davis D, Vasudevan A. Sciatica. [Updated 2019 Feb 28]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2019 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK507908/.
Lumbar disc herniation
A lumbar herniated disc can inflame a nearby nerve root, leading to sciatica pain.
The bulging and/or extrusion of the inner core of a spinal disc in the lower back may cause nerve root irritation or compression through 2 mechanisms: the leaking of certain chemicals from the disc and direct mechanical pressure.
Lumbar degenerative disc disease
Weakened discs in the lower back allow excess motion in the spine and may cause irritation of the nerve roots.
Isthmic spondylolisthesis
Vertebral slippage can inflame or compress a nearby nerve root.
A condition where one vertebra slips over another and pinches a nerve root.
Lumbar spinal stenosis
Narrowing of bony openings in the spine, which may cause compression of nerve roots as they exit the spinal canal.
Rarely, spinal tumors and infections may cause sciatica and require immediate medical attention.
Read more about Sciatica Causes
Sciatica Symptoms Vary Based on the Affected Nerve Roots
Sciatica pain originates in the lower back and travels down the leg, occasionally affecting the feet and toes.
Sciatica pain travels down from the lower back, into the leg, and may sometimes affect the feet and toes. Other sensations associated with sciatica may include tingling, numbness, burning, and/or a prickly feeling.
Depending on the location of nerve compression, different sciatica symptoms may be experienced. For example, the L5 and S1 nerve roots are commonly affected and may cause the following symptoms:
- Sciatica from the L5 nerve root may cause pain along the outer part of the thigh and leg, and weakness while lifting the foot.
- Sciatica from the S1 nerve root may cause pain in the calf and foot, and numbness along the outer side of the foot and in the third, fourth, and fifth toes.
Typically sciatica symptoms affect one leg at a time. Rarely, both legs may be affected if the underlying cause compresses the left and right nerve roots together. 5 Ombregt L. The dural concept. In: A System of Orthopaedic Medicine. Elsevier; 2013:447-472.e4. doi:10.1016/b978-0-7020-3145-8.00033-8. The severity and duration of pain from sciatica can also vary. Most commonly, a sharp, burning, or searing pain may be felt. Sometimes, the pain may be a dull ache or a mild discomfort that comes and goes.
It is important to understand that sciatica is radiculopathy and originates from the sciatic nerve roots (L4 to S3) in the lower spine. 2 Giuffre BA, Jeanmonod R. Anatomy, Sciatic Nerve. [Updated 2018 Dec 16]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2019 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK482431/. Sciatica-type symptoms may occur in other conditions, such as hip arthritis, piriformis syndrome, or sacroiliac joint dysfunction, but are not medically considered to be sciatica.

- Sciatica originates in the lower back. Compression or irritation of a nerve root between spinal levels L4 to S3 in the lower back causes sciatica. These nerve roots merge to form the large, bulky sciatic nerve, which travels down the leg and terminates in the foot, causing the symptoms to follow this course.
- Sciatica describes a set of symptoms. The term sciatica is defined by a set of symptoms, such as pain, tingling, numbness, and/or weakness, caused by an underlying medical condition.
- Sciatica overlaps with multiple diagnoses. Sciatica symptoms can occur due to several conditions that affect the lower back, such as herniated or degenerated lumbar discs, spinal stenosis, or spondylolisthesis.
- Sciatica symptoms differ based on the nerve root. The specific symptoms of sciatica are dictated by the exact nerve root that is pinched or irritated. Commonly affected nerve roots are L5, which causes weakness in the foot, and S1, which causes marked pain along the back of the thigh.
- Sciatica can be described by multiple terms. The medical term for sciatica is lumbar radiculopathy. Sciatica can also be referred to as pinched or compressed nerve pain in the leg.
- Sciatica relief typically comes quickly. Most people who experience sciatica find relief from their symptoms within 6 to 12 weeks and will not need to consider invasive treatments, such as surgery.
- Sciatica-like symptoms can occur in pelvic or hip conditions. Degeneration or compression of the body of the sciatic nerve or its branches in the pelvis, hip, thigh, or leg can mimic sciatica pain. A common example is piriformis syndrome.
- Serious sciatica symptoms require immediate attention. Red-flag symptoms and signs, such as bladder or bowel incontinence, pain in the groin, and/or worsening leg pain, may indicate a serious medical condition and warrant immediate medical attention.
This information is not intended or implied as a substitute for medical advice, diagnosis or treatment. All content, including text, graphics, images or other information provided is intended for general information purposes only. Always consult with your physician for diagnosis or treatment.
- 1 Cook CE, Taylor J, Wright A, Milosavljevic S, Goode A, Whitford M. Risk Factors for First Time Incidence Sciatica: A Systematic Review. Physiotherapy Research International. 2013;19(2):65-78. doi:10.1002/pri.1572.
- 2 Giuffre BA, Jeanmonod R. Anatomy, Sciatic Nerve. [Updated 2018 Dec 16]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2019 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK482431/.
- 3 Hernández C.P., Sanchez N., Navarro-Siguero A., Saldaña M.T. (2013) What is Sciatica and Radicular Pain?. In: Laroche F., Perrot S. (eds) Managing Sciatica and Radicular Pain in Primary Care Practice. Springer Healthcare, Tarporley. https://doi.org/10.1007/978-1-907673-56-6_1.
- 4 Davis D, Vasudevan A. Sciatica. [Updated 2019 Feb 28]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2019 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK507908/.
- 5 Ombregt L. The dural concept. In: A System of Orthopaedic Medicine. Elsevier; 2013:447-472.e4. doi:10.1016/b978-0-7020-3145-8.00033-8.