Can an L5-S1 Problem Cause Groin Pain?

An L5-S1 disc herniation or degenerative problem can absolutely cause groin pain, even though the groin sits far from where you would expect a lower-back issue to send symptoms. The connection runs through a small nerve called the sinuvertebral nerve, which feeds sensory information from the disc and surrounding structures into the sympathetic trunk and ultimately tricks the brain into perceiving pain in the groin. This referral pattern catches many patients and clinicians off guard because classic teaching focuses on L5-S1 sending pain down the back of the leg into the foot, not toward the front of the pelvis.

The Sinuvertebral Nerve and How It Reroutes Pain

The sinuvertebral nerve, sometimes called Luschka’s nerve, innervates the back portion of the intervertebral disc, the posterior longitudinal ligament, and the dura surrounding the spinal cord. When a disc herniation or other structural problem at L5-S1 irritates this nerve, the signal does not simply travel along the L5 or S1 nerve root the way a typical sciatica symptom would. Instead, the sensory input travels through the sympathetic trunk, a chain of nerve connections running alongside the spine that links the autonomic nervous system to the spinal cord at multiple levels. Through this pathway, the signal reaches the dorsal root ganglion of the L1 nerve, which is the nerve level responsible for sensation in the groin area.¹

In simpler terms, the brain receives a pain signal that entered the spinal cord at L1 and interprets it as coming from the groin, even though the actual problem is several vertebral levels lower at L5-S1. This is a form of referred pain: the brain mislocates the source because pain signals from two different body regions converge on the same spinal neurons.² A case report specifically identified L5-S1 central herniation as a causative factor of groin pain through exactly this sinuvertebral-nerve-to-sympathetic-trunk-to-L1 route, confirming the mechanism in a clinical setting.³

Why Textbook Dermatome Maps Miss This

Most anatomy charts show the L5 dermatome covering the outer shin and top of the foot, and S1 covering the outer ankle and sole. The groin, by contrast, sits in the L1 territory. So if you look at a standard dermatome chart, there is no obvious reason an L5-S1 problem should cause groin pain. This is one reason the connection gets overlooked so often.

But dermatome maps are idealized diagrams, not reliable predictions for any individual patient. A study that deliberately provoked lumbosacral nerve roots and mapped where patients actually felt symptoms found that pain referral was usually outside the expected dermatomal pattern for a given spinal level.⁴ In other words, the neat color-coded maps in textbooks often do not reflect what happens in a living person. Pain can show up in areas that seem anatomically unrelated to the compressed nerve root. The sinuvertebral nerve pathway described above is one reason this happens at L5-S1, but the broader point is that referred pain from the spine is messier and more widespread than most people assume.

Research on the underlying biology supports this. Sensory neurons in the lumbar dorsal root ganglia can send branching fibers to both the lumbar disc and to tissues far from the disc itself. The proportion of these “dichotomizing” nerve fibers helps explain how a disc problem at one level creates pain that feels like it belongs to a completely different part of the body.⁵ Two main theories account for referred pain generally: central sensitization, where spinal cord neurons that receive input from multiple areas become hyperexcitable, and peripheral reflexes through these branching nerve fibers that physically connect two distant tissues.⁶ Both mechanisms likely contribute to groin symptoms from lower lumbar disc disease.

It Is Not Just Disc Herniations

A bulging or herniated disc at L5-S1 is the most commonly discussed cause of referred groin pain from the lower spine, but it is not the only one. Facet joint problems at L4-L5 and L5-S1 can also refer pain to the groin and inner thigh. This “pseudo-radicular” pain pattern typically radiates from the lower back to the buttock and trochanteric region and can extend into the groin and thighs, ending above the knee, without the neurological deficits you would see with a true pinched nerve.⁷ Because there is no numbness, weakness, or reflex change, the pain is easily attributed to the hip joint itself or to a muscle strain.

Disc degeneration without a frank herniation can also be involved. One study documented persistent groin pain caused by lumbar disc degeneration that resolved after anterior interbody fusion surgery, with pain scores dropping significantly by one year after the procedure.⁸ The disc does not have to be dramatically herniated to irritate the sinuvertebral nerve; even internal disruption or chronic inflammation within a degenerating disc can generate enough irritation to trigger the referral pathway.

How Often Groin Pain Traces Back to the Lumbar Spine

Pinning down a precise frequency is difficult because groin pain has a long list of potential sources, and many patients carry more than one problem at once. However, the existing data give a sense of how often the lumbar spine turns out to be the culprit when other diagnoses have been considered first.

A retrospective study of young adults with chronic hip pain that had been undiagnosed or misdiagnosed by their initial doctors found that referred pain from the lumbar spine accounted for about 9% of final diagnoses. Within that group, lumbar disc herniation and spinal stenosis were the main spinal problems identified.⁹ Nearly one in ten patients in that cohort had been chasing hip-area solutions for what turned out to be a spine problem.

Another study looking specifically at groin pain in patients with lumbar disc herniation found that of those with a confirmed herniation, roughly 8% reported groin pain. Among those patients, two out of ten had the corresponding nerve root at L5, placing their problem in the lower lumbar spine rather than the upper levels you might expect to cause groin symptoms.¹⁰ That same study also found a much higher rate of groin pain among patients with sacroiliac joint dysfunction, at nearly 47%, reminding clinicians that the pelvis and the lower spine sit close together anatomically and can both produce overlapping groin symptoms.

The Hip-Spine Diagnostic Tangle

One of the most frustrating aspects for patients is the overlap between hip joint problems and lumbar spine problems. Both can cause groin pain, both can refer discomfort into the thigh, and both can coexist. The medical literature calls this overlap “hip-spine syndrome,” and it is a genuine headache for clinicians trying to figure out which structure is the primary pain generator.

Groin pain is the most common distribution of pain from intra-articular hip problems like osteoarthritis, and roughly half of people with hip osteoarthritis also have pain radiating below the knee, further blurring the line between hip and spine symptoms.¹¹ So even the presence of knee or thigh pain does not cleanly separate the two. In the case report involving a patient with both femoroacetabular impingement and an L5-S1 central herniation, an injection of local anesthetic into the hip joint initially improved groin pain, which seemed to confirm a hip source. But the groin pain ultimately required treatment of the lumbar disc problem as well.³ This is a scenario clinicians increasingly recognize: a diagnostic injection that partially works can mislead everyone into thinking the hip is the sole problem when the spine is also contributing.

If you have been told your groin pain is “from the hip” but hip-directed treatments have only helped partway, or not at all, the lumbar spine is worth investigating. Similarly, if you have a known L5-S1 disc issue and develop groin pain that does not match the expected leg pattern, the disc may be the source rather than a new hip or inguinal problem.

When Groin Pain Mimics Urological or Pelvic Conditions

The overlap with hip problems gets most of the attention, but lumbar disc disease can also mimic urological and pelvic conditions. The groin, lower abdomen, and perineum share sensory nerve supply through the iliohypogastric, ilioinguinal, genitofemoral, and pudendal nerves, all of which have afferent fibers originating from thoracolumbar and sacral nerve roots. Compression or irritation of these roots, particularly at the L4-S1 levels, can produce referred pain patterns that closely resemble conditions like chronic prostatitis or chronic pelvic pain syndrome in men.¹²

Cases have been documented where patients undergo rounds of urological testing and treatment for pelvic pain before anyone thinks to image the lumbar spine. This is especially likely when the patient’s back pain is mild or absent. Many people with L5-S1 disc problems do not have dramatic back pain; their primary symptom can be purely in the groin or pelvic region, which sends both patient and doctor looking in the wrong direction for months or years. If urological workups come back clean and pelvic-floor therapy does not resolve the pain, a lumbar MRI is a reasonable next step that often gets ordered too late in the process.

Clues That Point Toward the Spine

There is no single test that definitively separates spine-referred groin pain from hip or inguinal causes, but several clinical features tilt the odds:

Positional changes: Groin pain that worsens with sitting, bending forward, or coughing and sneezing tends to implicate the disc, because these movements increase intradiscal pressure and can further irritate the sinuvertebral nerve.
Concurrent back or buttock pain: Even mild low back discomfort alongside the groin pain raises suspicion for a spinal source, though as noted above, some patients have no back pain at all.
Central disc herniation: The sinuvertebral nerve mechanism tends to involve central or paracentral herniations rather than the far-lateral herniations that typically compress the exiting nerve root and send pain down the leg.³
Negative hip exam: Full range of motion at the hip without reproducible groin pain on impingement testing (flexion, adduction, internal rotation) weakens the case for a hip source.
Diagnostic injection response: If an intra-articular hip injection fails to relieve groin pain, or only partially helps, the spine deserves scrutiny. Conversely, an epidural steroid injection at the involved lumbar level that relieves groin pain provides strong evidence that the spine is the source.

Diagnostic nerve blocks and selective injections remain the closest thing to a definitive test for differentiating spine from hip causes. They are imperfect and sometimes produce confusing results when both structures contribute, but they offer more certainty than imaging alone.

Treatment When L5-S1 Is Confirmed as the Source

Once the lumbar spine is identified as the groin pain generator, treatment follows the same general pathway as for other symptoms caused by disc herniation or degeneration at L5-S1. Most clinicians start with conservative care: physical therapy focused on core stabilization and lumbar mobility, oral anti-inflammatory medication, and activity modification. Patients who do not improve after about six weeks of conservative management are typically considered for epidural steroid injections. Both caudal and transforaminal routes have been used for L5-S1 discogenic radicular pain in patients who failed initial conservative care.¹³

When conservative and injection-based approaches do not provide lasting relief, surgical options come into play. A study of patients who underwent percutaneous endoscopic discectomy specifically for discogenic groin pain reported that pain scores dropped dramatically within the first week and remained low throughout a 12-month follow-up period, with a 100% effective rate and good-to-excellent results in over 93% of patients.¹⁴ For cases involving disc degeneration rather than a discrete herniation, fusion surgery has also shown significant groin pain improvement at one year.⁸

The key takeaway from the surgical data is that when the spine is correctly identified as the cause, treating it resolves the groin pain in most cases. The challenge, as the previous sections make clear, is reaching that correct identification in the first place. Patients who have bounced between orthopedic hip surgeons, urologists, and sports-medicine providers without a clear answer may find it worth requesting a lumbar MRI and, if imaging shows a disc problem at L5-S1, discussing the sinuvertebral nerve referral pathway with their provider.

Why Central Herniations Behave Differently

A detail worth understanding is that the type of disc herniation matters for whether groin pain is likely. Most L5-S1 herniations push out posterolaterally, compressing the traversing S1 nerve root and causing classic sciatica down the back of the leg. These do not typically produce groin pain because the sinuvertebral nerve is not the primary structure being irritated. Central herniations, which protrude straight backward into the spinal canal, are more likely to irritate the sinuvertebral nerve and the posterior longitudinal ligament, activating the sympathetic-trunk referral pathway to L1 and producing groin symptoms.¹

This distinction has practical implications. If your MRI report describes a “central” or “broad-based central” disc protrusion at L5-S1 and you have groin pain, the correlation is more plausible than if the herniation is described as “far lateral” or “foraminal.” Radiologists and spine specialists who are aware of this mechanism will sometimes specifically flag a central herniation in the context of unexplained groin symptoms. Unfortunately, many imaging reports are read without knowledge of the patient’s groin complaint, and the connection goes unrecognized. Bringing the groin pain to the attention of whoever is interpreting your MRI can make a meaningful difference.

Sacroiliac Joint Problems and Groin Pain

Because the diagnostic workup for groin pain often involves the lumbar spine and the hip, the sacroiliac joint sometimes gets overlooked as a third potential contributor. In one study, nearly half of patients with sacroiliac joint dysfunction reported groin pain, a rate substantially higher than the rate seen with lumbar disc herniation or spinal stenosis in the same cohort.¹⁰ The sacroiliac joint sits immediately adjacent to L5-S1 and shares some nerve supply through the sacral plexus, which is why its pain referral patterns overlap with both lumbar and hip sources.

For patients who have a relatively unremarkable lumbar MRI and a normal hip exam but persistent groin pain, provocative testing of the sacroiliac joint (compression and distraction tests, FABER test) and ultimately a diagnostic sacroiliac joint injection can help clarify whether this joint is the culprit. In clinical practice, all three structures — the lumbar disc, the hip, and the sacroiliac joint — should be considered systematically rather than investigated one at a time over months of specialist referrals. Patients sometimes advocate most effectively for themselves by explicitly asking each provider whether the other two sources have been ruled out.

1
PubMed. Groin pain associated with lower lumbar disc herniation
2
Egyptian Journal of Radiology and Nuclear Medicine. MRI case in groin pain syndrome: do not neglect to consider the sinuvertebral nerve (Luschka’s nerve)
3
JOS Case Reports. Sinu-vertebral nerve-induced groin pain as a combined symptom of femoroacetabular impingement and lumbar disc herniation: A case report
4
PubMed. Induced lumbosacral radicular symptom referral patterns: a descriptive study
5
PubMed. Dorsoventral organization of sensory nerves in the lumbar spine as indicated by double labeling of dorsal root ganglion neurons
6
PubMed Central. Referred pain: characteristics, possible mechanisms, and clinical management
7
PubMed Central. Facet joint syndrome: from diagnosis to interventional management
8
Spine. Lumbar Disc Degeneration Induces Persistent Groin Pain
9
PubMed Central. Causes of Chronic Hip Pain Undiagnosed or Misdiagnosed by Primary Physicians in Young Adult Patients: a Retrospective Descriptive Study
10
Elsevier / PubMed Central. Groin pain associated with sacroiliac joint dysfunction and lumbar disorders
11
PubMed Central. Links between the Hip and the Lumbar Spine (Hip Spine Syndrome) as they Relate to Clinical Decision Making for Patients with Lumbopelvic Pain
12
PubMed Central. Is Lumbar Disk Herniation a Potential Risk Factor for Chronic Prostatitis/Chronic Pelvic Pain Syndrome? Insights From a Misdiagnosed Case
13
PubMed Central. Comparative Efficacy and Safety of Fluoroscopy-guided Caudal Epidural Steroid Injection and Transforaminal Epidural Steroid Injection for Unilateral L5-S1 Paracentral Discogenic Radicular Pain
14
PubMed. Pathomechanism of Lower-level Discogenic Groin Pain and Clinical Outcomes of Percutaneous Endoscopic Discectomy for the Treatment of Discogenic Groin Pain