The lumbosacral joint, also called L5-S1, is a term used to describe a part of the spine. L5-S1 is the exact spot where thelumbar spineends and the sacral spine begins. The lumbosacral joint connects these bones.
L5-S1 is vulnerable to misalignment and injury. It can also be the site of a disc herniation or a spine disorder calledspondylolisthesis.
Function and Anatomy
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The spinal column is the structure that allows you to stand upright. It also helps you twist, bend, and otherwise alter your trunk and neck position.
There are typically 24 movable bones in the spine that connect to thesacrum(a bony structure located below the lumbar vertebrae) and thecoccyx(also called the tailbone). The sacrum and the coccyx each consist of multiple bones that fuse over time.
L5-S1 consists of the last bone in the lumbar spine (low back), called L5, and the triangle-shaped bone under it, known as the sacrum. The sacrum is made of five fused bones—S1 is at the top.
Injury Risk
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Each area of the spine has a curve, and these curves go in opposing directions. The areas where the spinal curve directions change are called junctional levels. Injury risk may be higher at junctional levels because your body weight shifts direction as the curves shift directions.
The L5-S1 junction is located between the lumbar curve and the sacral curve. The lumbar curve sweeps forward. The sacral curve opposes the direction of the lumbar curve, going backward.
The L5-S1 junction is particularly vulnerable to misalignment, wear and tear, and injury. This is because, in most people, the top of the sacrum is positioned at an angle. Aging and injury may increase the vulnerability of the L5-S1 junction even more.
Pain from L5-S1 is typically treated with heat or ice, over-the-counter anti-inflammatory medications, prescription pain medicine or muscle relaxers, physical therapy, chiropractic adjustments, and epidural steroid injections. If these measures do not help, surgery may be required.
L5-S1 is one of the two most common sites for back surgery. The other is the area just above, called L4-L5.
Related Conditions
In the low back, the L5-S1 junction is often the site of a problem known asspondylolisthesis. Disc herniation at L5-S1 is also possible and is a common cause of sciatica—a problem with the sciatic nerve that can cause pain and other issues.
Disc Herniation
Discs separate the vertebrae (spinal bones), cushioning the spinal column and allowing for movement between vertebrae. Adisc herniationmeans the disc slips out of place.
A disc herniation at L5-S1 is a common cause of sciatica. Symptoms ofsciaticainclude:
Disc problems at L5-S1 herniation can also cause lower back pain and stiffness, as well as trigger painful muscle spasms that cause your back to go out.
Bowel problems are also possible with disc problems at L5-S1. Some research links irritable bowel syndrome to herniated discs in the lower back.Additional studies found disc problems at L5-S1 can lead to difficulty controlling your anal sphincter.
Initial treatments for disc herniation include rest and pain relievers—and later physical therapy. Most people recover with these interventions. Those who don’t may require asteroid injectionor surgery.
Spondylolisthesis
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Spondylolisthesis occurs when a vertebra slips forward relative to the bone beneath it.
The most common variety of this condition is called degenerative spondylolisthesis. It generally occurs when the spine starts to wear down with age.
Isthmicspondylolisthesis is another common variant. Isthmic spondylolisthesis starts as a tiny fracture in thepars interarticularis—a bone area in the back that connects the adjoining parts of thefacet joint.While these types of fractures tend to occur before the age of 15, symptoms often do not develop until adulthood. Degeneration of the spine in later adulthood can further worsen the condition.
The angle of the sacrum may contribute to spondylolisthesis. This is because the S1 tips down in the front and up in the back rather than being horizontal to the ground. Individuals with a greater tilt will usually have a higher risk of spondylolisthesis.
People with spondylolisthesis may not have any symptoms. Those who do may experience:
Spondylolisthesis is typically treated with non-surgical interventions. These could include:
Summary
The L5-S1 is also called the lumbosacral joint. It is the part of the spine where the lumbar spine ends and the sacral spine begins. It helps you twist, bend, and stand upright.
Because of its location, the L5-S1 is vulnerable to wear and tear and injury. One of the more common problems with the L5-S1 is spondylolisthesis, which occurs when a vertebra slips forward. Disc herniation at L5-S1 is also possible. These conditions are usually treated non-surgically.
8 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.MedlinePlus.Sciatica.MedlinePlus.Herniated disk.American Association of Neurological Surgeons.Herniate disc.Bertilson BC, Heidermakr A, Stockhaus M.Irritable bowel syndrome–a neurological spine problem.JAMMR. 2015;4(24):4154–68. doi:10.9734/BJMMR/2014/9746Akca N, Ozdemir B, Kanat A, Batcik OE, Yazar U, Zorba OU.Describing a new syndrome in L5-S1 disc herniation: Sexual and sphincter dysfunction without pain and muscle weakness.J Craniovertebr Junction Spine. 2014;5(4):146–50. doi:10.4103/0974-8237.147076American Academy of Orthopaedic Surgeons.Spondylolysis and spondylolisthesis.Gong S, Hou Q, Chu Y, Huang X, Yang W, Wang Z.Anatomical factors and pathological parts of isthmic fissure and degenerative lumbar spondylolisthesis.Chronic Dis Prev Rev. 2019;9:1-6American Academy of Orthopaedic Surgeons.Spondylolysis and spondylolisthesis.
8 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.MedlinePlus.Sciatica.MedlinePlus.Herniated disk.American Association of Neurological Surgeons.Herniate disc.Bertilson BC, Heidermakr A, Stockhaus M.Irritable bowel syndrome–a neurological spine problem.JAMMR. 2015;4(24):4154–68. doi:10.9734/BJMMR/2014/9746Akca N, Ozdemir B, Kanat A, Batcik OE, Yazar U, Zorba OU.Describing a new syndrome in L5-S1 disc herniation: Sexual and sphincter dysfunction without pain and muscle weakness.J Craniovertebr Junction Spine. 2014;5(4):146–50. doi:10.4103/0974-8237.147076American Academy of Orthopaedic Surgeons.Spondylolysis and spondylolisthesis.Gong S, Hou Q, Chu Y, Huang X, Yang W, Wang Z.Anatomical factors and pathological parts of isthmic fissure and degenerative lumbar spondylolisthesis.Chronic Dis Prev Rev. 2019;9:1-6American Academy of Orthopaedic Surgeons.Spondylolysis and spondylolisthesis.
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
MedlinePlus.Sciatica.MedlinePlus.Herniated disk.American Association of Neurological Surgeons.Herniate disc.Bertilson BC, Heidermakr A, Stockhaus M.Irritable bowel syndrome–a neurological spine problem.JAMMR. 2015;4(24):4154–68. doi:10.9734/BJMMR/2014/9746Akca N, Ozdemir B, Kanat A, Batcik OE, Yazar U, Zorba OU.Describing a new syndrome in L5-S1 disc herniation: Sexual and sphincter dysfunction without pain and muscle weakness.J Craniovertebr Junction Spine. 2014;5(4):146–50. doi:10.4103/0974-8237.147076American Academy of Orthopaedic Surgeons.Spondylolysis and spondylolisthesis.Gong S, Hou Q, Chu Y, Huang X, Yang W, Wang Z.Anatomical factors and pathological parts of isthmic fissure and degenerative lumbar spondylolisthesis.Chronic Dis Prev Rev. 2019;9:1-6American Academy of Orthopaedic Surgeons.Spondylolysis and spondylolisthesis.
MedlinePlus.Sciatica.
MedlinePlus.Herniated disk.
American Association of Neurological Surgeons.Herniate disc.
Bertilson BC, Heidermakr A, Stockhaus M.Irritable bowel syndrome–a neurological spine problem.JAMMR. 2015;4(24):4154–68. doi:10.9734/BJMMR/2014/9746
Akca N, Ozdemir B, Kanat A, Batcik OE, Yazar U, Zorba OU.Describing a new syndrome in L5-S1 disc herniation: Sexual and sphincter dysfunction without pain and muscle weakness.J Craniovertebr Junction Spine. 2014;5(4):146–50. doi:10.4103/0974-8237.147076
American Academy of Orthopaedic Surgeons.Spondylolysis and spondylolisthesis.
Gong S, Hou Q, Chu Y, Huang X, Yang W, Wang Z.Anatomical factors and pathological parts of isthmic fissure and degenerative lumbar spondylolisthesis.Chronic Dis Prev Rev. 2019;9:1-6
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