Sciatica Part 2: Beyond the Spine
Deep Gluteal Syndrome, Nerve Entrapment, and Diagnosis
In Part 1, we explored how irritation of a spinal nerve root, often associated with lumbar disc herniation, can produce sciatica. We also saw why the size of a disc finding does not determine pain, recovery, or the need for surgery.
But what happens when the lumbar spine does not fully explain the symptoms?
In some people, pain, tingling, numbness, or weakness may arise farther along the sciatic pathway. The nerve can become irritated within the pelvis, deep gluteal region, or upper thigh. This group of conditions is often discussed under the broader term deep gluteal syndrome.
In Part 2, we will explore:
How sciatic-type symptoms can arise outside the lumbar spine
The anatomical structures that may affect the sciatic nerve
The roles of fibrous bands, previous injury, muscular structures, and reduced space around the nerve
How orthopedic, neurological, and vascular examinations help distinguish among possible causes
When standard imaging, ultrasound, or magnetic resonance neurography may contribute useful information
These conditions are less common than lumbar nerve-root irritation and can be difficult to identify. Buttock and leg pain may also arise from the hip, sacroiliac region, muscles, blood vessels, or other peripheral nerves.
This exploration will provide a broader understanding of sciatica and how to approach it from a diagnostic and treatment standpoint.
Article Index:
Deep Gluteal Syndrome: Sciatic Pain Beyond the Spine
Not all sciatic symptoms begin in the lumbar spine. In a smaller group of patients, the sciatic nerve may become irritated or compressed after it leaves the pelvis and enters the deep gluteal region.
This is known as Deep Gluteal Syndrome (DGS), an umbrella term for non-disc-related sciatic nerve entrapment within the space beneath the gluteal muscles. It may produce deep buttock pain that extends into the back of the thigh or lower leg. Tingling, numbness, and pain aggravated by prolonged sitting are also common.
Several structures or conditions may contribute:
Piriformis-related entrapment: The sciatic nerve may be affected by the piriformis muscle, its fascia, or anatomical variations in this region. Piriformis syndrome is one possible form of DGS, not the explanation for every case of buttock pain.
Other deep gluteal structures: The obturator internus, gemelli, quadratus femoris, hamstring origin, and surrounding connective tissues may affect the space available to the nerve.
Fibrous or fibrovascular bands: Bands crossing beside or over the nerve have been observed during endoscopic procedures and may restrict its movement or contribute to compression.
Previous injury or surgery: Trauma, bleeding, inflammation, or scar formation can alter the tissues surrounding the nerve.
Reduced anatomical space: Ischiofemoral impingement, structural variation, or less commonly a mass or vascular abnormality may affect the sciatic pathway.
The sciatic nerve is not fixed in place. It normally glides relative to surrounding tissues as the hip and knee move. When the nerve’s available space or mobility is reduced, mechanical loading and local irritation may contribute to symptoms. Prolonged or substantial compression can also affect the nerve’s circulation and function, but this should not be assumed in every case.
The Clinical Perspective on Sciatica
Deep gluteal syndrome can resemble lumbar radicular pain, hip pathology, sacroiliac pain, proximal hamstring injury, and referred pain from surrounding muscles. No symptom or physical test confirms DGS by itself.
Diagnosis requires the history, neurological findings, symptom behaviour, hip and lumbar examination, and imaging when indicated to form a consistent pattern. New or progressive weakness requires prompt neurological assessment rather than an assumption that the symptoms arise from muscular tightness.
Lumbar nerve-root irritation remains a more common explanation for sciatica. DGS should be considered when the clinical findings direct attention beyond the spine.
Where Entrapment May Occur
Outside the spine, the sciatic nerve may become irritated or restricted at several locations within the deep gluteal region:
Near the greater sciatic notch and piriformis: The nerve passes through a confined area beneath, or occasionally through, the piriformis muscle.
Along the obturator internus and gemelli complex: These deep hip muscles lie close to the nerve and may influence the space available to it during movement.
Within the ischiofemoral space: Reduced space beside the quadratus femoris may affect the sciatic nerve and other nearby tissues.
Near the proximal hamstring attachment: Previous injury, scarring, or changes around the ischial tuberosity may restrict the nerve within the ischial tunnel.
Possible symptoms include deep buttock pain, pain or tingling extending down the leg, and discomfort aggravated by prolonged sitting or particular hip movements. Weakness may occur, but it requires careful neurological assessment because a problem at the lumbar nerve root can produce similar findings.
Groin discomfort or substantially restricted hip movement may also point toward a hip or ischiofemoral condition rather than isolated sciatic nerve entrapment.
Clinical Perspective
Pain location alone cannot identify where the sciatic nerve is being irritated. For practitioners, the important task is to determine whether the person’s history, neurological findings, movement-related symptoms, physical examination, and imaging when indicated support entrapment in the deep gluteal space.
For patients, the practical message is simple: persistent buttock and leg pain does not always begin at a spinal disc, but a fibrous band or “tight muscle” should not be assumed without a thorough assessment.
Where Can the Sciatic Nerve Be Compressed?
Most sciatica begins with irritation of a nerve root in the lumbar spine. Less commonly, the sciatic nerve itself may be irritated or compressed after it leaves the pelvis and travels through the deep gluteal region.
Potential sites include the piriformis, the gemelli-obturator internus complex, the ischiofemoral space, and the proximal hamstring attachment. Fibrous or fibrovascular bands, previous trauma, surgery, and other space-occupying abnormalities may also affect the nerve.
These conditions fall within the broader category of deep gluteal syndrome. They can resemble lumbar radicular pain, which is why the location of pain alone is not enough to determine its source.
Piriformis Syndrome: A Diagnosis That Requires Caution
The sciatic nerve usually passes beneath the piriformis, although anatomical variations exist. In some people, the nerve may become irritated near the muscle because of local anatomy, trauma, scarring, altered movement, or compression during particular hip positions.
An anatomical variation does not, by itself, confirm piriformis syndrome. Similar symptoms can arise from a lumbar disc, spinal stenosis, the sacroiliac region, the hip, or other structures within the deep gluteal space.
Piriformis syndrome is therefore best viewed as one possible form of deep gluteal syndrome, not as the default explanation for every combination of buttock and leg pain. Diagnosis requires clinical findings that support irritation near the piriformis while other, more common causes are considered.
Gemelli-Obturator Internus Entrapment
The superior and inferior gemelli and obturator internus form part of the deep lateral rotator group of the hip. As the sciatic nerve travels through this region, its movement may be influenced by the surrounding muscles, fascia, and available space.
Entrapment in this area is uncommon, but it may be considered when deep buttock pain is aggravated by sitting or particular hip movements and the lumbar examination does not adequately explain the symptoms.
A Connected Anatomical System
My experience in the dissection lab reinforced how closely the deep hip rotators are connected through fascia and their shared anatomical environment. Although each muscle has identifiable attachments and functions, they do not operate independently during movement.
For practitioners, this supports examining the region as a coordinated system. It does not mean that every fascial restriction is pathological or that treating one connective-tissue structure will necessarily resolve sciatic symptoms. Anatomical relationships must still be interpreted alongside neurological findings, symptom behaviour, and functional testing.
Image note: Carla Stecco’s Functional Atlas of the Human Fascial System provides an excellent anatomical view of this region. Any reproduced image should include complete attribution and appropriate permission from the copyright holder.
Ischiofemoral Impingement
Ischiofemoral impingement occurs when the space between the ischium and the lesser trochanter of the femur becomes reduced. This can compress or irritate the quadratus femoris muscle, particularly during hip extension, adduction, or long-stride walking.
People may experience deep buttock, groin, or posterior hip pain. Because the sciatic nerve lies nearby, some may also develop radiating pain or altered sensation, but neurological symptoms are not present in every case.
Structural anatomy, previous hip surgery or trauma, movement patterns, and changes in surrounding muscles may contribute. MRI can reveal narrowing of the ischiofemoral space and changes within the quadratus femoris, but these findings must correspond with the patient’s symptoms and examination. Narrowing on imaging alone does not confirm a painful condition.
Proximal Hamstring-Related Sciatic Irritation
The sciatic nerve passes close to the proximal hamstring tendons near the ischial tuberosity. A hamstring tear, tendinopathy, or previous injury may produce inflammation or scar tissue that irritates the nerve or restricts its movement.
Typical features may include pain near the sitting bone, discomfort with prolonged sitting, and symptoms aggravated by running, bending at the hip, or stretching the hamstrings. Radiating pain, tingling, or weakness raises the possibility of sciatic nerve involvement and warrants a neurological assessment.
The examination should distinguish proximal hamstring pathology from lumbar nerve-root irritation, deep gluteal syndrome, hip pathology, and other causes of posterior thigh pain.
The Clinical Takeaway
Sciatic symptoms arising in the deep gluteal region are possible, but they are less common than lumbar nerve-root irritation. Neither tenderness, muscle tension, nor pain with sitting can confirm the site of compression.
The diagnosis should bring together:
The location and behaviour of symptoms
Lumbar spine and hip examination findings
Strength, sensation, and reflex testing
Neurodynamic testing
The history of trauma, surgery, or hamstring injury
Imaging or other investigations when clinically indicated
For patients, the important point is that buttock and leg pain can have several sources. For practitioners, the challenge is not simply finding a tight or tender structure. It is determining whether that structure plausibly explains the entire clinical presentation.
Physical Examination: Following the Evidence
Sciatica-like pain can arise from the lumbar spine, a spinal nerve root, the sciatic nerve itself, or another structure that refers pain into the leg. The physical examination helps determine which explanation best fits the entire clinical picture.
The assessment begins with the history:
Where did the symptoms begin, and where do they travel?
Are they aggravated by sitting, walking, bending, coughing, or particular hip movements?
Is there numbness, tingling, weakness, or loss of coordination?
Was there a recent injury, surgery, infection, or unexplained change in health?
Are any urgent warning signs present?
The practitioner then observes posture, walking, balance, and functional movements before examining the lumbar spine, pelvis, hips, and lower limbs. Orthopedic and neurodynamic procedures, such as the straight-leg raise or slump test, may reproduce symptoms associated with neural sensitivity. Hip movements and deep gluteal provocation tests may be added when symptoms suggest involvement beyond the spine.
No single test confirms sciatica or identifies its source. The value comes from patterns across the history and examination.
Low Back Examination
This video demonstrates orthopedic procedures commonly used when assessing low back and leg symptoms. The examination evaluates movement, symptom responses, joint and soft-tissue findings, and possible neural involvement.
For patients, these tests help clarify where symptoms may be coming from. For practitioners, they provide information that must be interpreted alongside the neurological examination and the patient’s history, rather than used as isolated diagnostic answers.
Neurological/Vascular Testing
A neurological examination helps determine whether a nerve root or peripheral nerve is affecting lower-limb function. It commonly includes:
Sensation: Comparing areas of altered sensitivity, recognizing that dermatomes overlap and vary between individuals
Strength: Testing muscles associated with particular nerve roots and peripheral nerves
Reflexes: Assessing responses such as the patellar and Achilles tendon reflexes
Neurodynamic testing: Evaluating how symptoms respond when the nervous system is placed under controlled mechanical load
Gait and balance: Looking for functional evidence of weakness, altered control, or neurological impairment
Muscle strength is commonly recorded on a 0-to-5 scale, while tendon reflexes may be graded from absent to unusually brisk. These scores are useful, but their significance comes from asymmetry, consistency, change over time, and how well they correspond with the other findings.
A normal neurological examination does not automatically exclude sciatic nerve irritation. Conversely, measurable weakness, altered reflexes, or objective sensory loss raises greater concern for neurological involvement and may change the need for imaging, referral, or treatment.
Lower Limb Neuro Examination
This video demonstrates the assessment of lower-limb strength, sensation, reflexes, and related neurological findings. These procedures help distinguish pain alone from radiculopathy, in which nerve dysfunction produces objective neurological changes.
The examination may also help differentiate a lumbar nerve-root problem from sciatic nerve involvement farther along its pathway.
Peripheral Vascular Examination
Leg pain is not always neurological. Reduced arterial circulation can cause cramping, aching, weakness, or fatigue during walking and may resemble spinal stenosis or sciatica.
A vascular assessment becomes particularly important when symptoms are brought on by walking, when pulses appear reduced, or when there are changes in skin colour, temperature, wound healing, or vascular risk factors. Depending on the findings, further medical assessment may be required.
This video demonstrates common components of a peripheral vascular examination, including observation of the lower limbs and assessment of circulation.
The purpose is not to diagnose every vascular condition during a musculoskeletal examination. It is to recognize findings that may indicate a circulatory explanation for leg symptoms and require further investigation.
The Clinical Takeaway
The examination is not a search for one positive test. It is a process of determining whether the history, symptom pattern, functional limitations, neurological findings, and orthopedic tests point toward the same source.
When the findings do not fit together, the diagnosis should remain open and further investigation may be appropriate.
When Imaging Helps
Most people with new, uncomplicated sciatica do not require immediate imaging. The history and physical examination usually provide enough information to begin conservative care.
Imaging becomes more important when:
Serious pathology is suspected
Significant or progressive weakness is present
Symptoms follow substantial trauma
Symptoms persist or worsen despite appropriate care
Surgery, an injection, or another invasive procedure is being considered
The examination suggests that symptoms may originate outside the lumbar spine
The purpose of imaging is not simply to find an abnormality. It is to determine whether an anatomical finding corresponds with the person’s symptoms, neurological findings, and functional limitations.
X-rays
X-rays show bones and spinal alignment but do not clearly display discs, nerve roots, or the sciatic nerve.
They may be useful when fracture, substantial degeneration, instability, deformity, or another bony condition is suspected. An X-ray cannot confirm sciatica and is not routinely required for uncomplicated nerve-related leg pain.
Magnetic Resonance Imaging
MRI provides detailed images of the intervertebral discs, spinal canal, nerve roots, and surrounding soft tissues. It may identify:
Disc herniation
Spinal or foraminal stenosis
Nerve-root compression
Infection, tumour, or other serious pathology
Soft-tissue abnormalities beyond the spine when the appropriate region is examined
MRI is generally the preferred imaging method when persistent or progressive neurological symptoms require further investigation. However, an MRI finding must match the clinical presentation. A disc bulge beside a nerve root does not prove that it is causing the person’s pain.
A standard lumbar MRI also may not adequately evaluate the sciatic nerve within the pelvis or deep gluteal region.
Imaging Beyond the Lumbar Spine
When the lumbar MRI does not explain the symptoms and deep gluteal syndrome is suspected, imaging may need to include the pelvis and hip.
Pelvic MRI can assess the deep gluteal space, proximal hamstring tendons, quadratus femoris, ischiofemoral space, and other structures surrounding the sciatic nerve. Specialized magnetic resonance neurography may provide additional information about the nerve itself, although availability and clinical usefulness vary.
Ultrasound
Musculoskeletal ultrasound can provide real-time images of the sciatic nerve and nearby muscles and tendons. It allows the examiner to observe the nerve during movement and compare one side with the other.
Ultrasound may support the assessment of proximal hamstring injuries, soft-tissue abnormalities, or suspected nerve entrapment. Its accuracy depends heavily on the equipment and examiner’s experience. Ultrasound findings alone cannot confirm piriformis syndrome or another form of deep gluteal syndrome.
Computed Tomography
CT provides detailed images of bone and may be useful when MRI cannot be performed or when fracture, bony narrowing, or complex pelvic anatomy requires closer assessment. Because it uses ionizing radiation and provides less soft-tissue detail than MRI, it is not usually the first choice for evaluating uncomplicated sciatica.
Imaging Is One Part of the Diagnosis
A scan may reveal anatomy, but it does not reveal the full clinical story. The most meaningful diagnosis comes from matching imaging findings with:
The distribution and behaviour of symptoms
Strength, sensation, and reflex findings
Lumbar and hip examination results
Neurodynamic responses
Functional limitations
Changes observed over time
For patients, an abnormal scan does not automatically mean permanent damage or surgery. For practitioners, imaging should answer a focused clinical question rather than replace the examination.
What Part 2 Teaches Us
Sciatica describes a pattern of symptoms, not a single cause. Although lumbar nerve-root irritation remains the most common explanation, the sciatic nerve may also be affected within the pelvis, deep gluteal region, ischiofemoral space, or near the proximal hamstring attachment.
Deep gluteal syndrome and other extraspinal causes should be considered when the history and examination do not fit a lumbar diagnosis. However, finding a tender muscle, restricted movement, or abnormality on imaging does not prove that it is responsible for the symptoms.
The most reliable conclusions emerge when several pieces of evidence point in the same direction:
The location and behaviour of symptoms
Strength, sensation, and reflex findings
Lumbar spine, hip, and pelvic examination
Neurodynamic testing
Imaging when clinically indicated
For patients, this means that persistent buttock and leg pain deserves a careful assessment rather than an automatic label. For practitioners, it means remaining open to multiple possibilities while giving greater weight to common and clinically supported explanations.
Coming Next: Treatment and Rehabilitation
In “Sciatica Part 3: Treatment and Rehabilitation,” we will examine how treatment decisions change according to the suspected source, neurological findings, symptom severity, and functional limitations.
We will explore the roles of education, activity modification, progressive exercise, neurodynamic procedures, spinal manipulation or mobilization, and soft-tissue treatment. We will also consider when conservative care is appropriate and when further medical assessment or surgical consultation may be necessary.
The goal is not to apply the same treatment to every person with sciatica. It is to match the treatment strategy to the clinical presentation.
References Part - 2
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Carro LP, Hernando MF, Cerezal L, Navarro IS, Fernandez AA, Castillo AO. Deep gluteal space problems: piriformis syndrome, ischiofemoral impingement and sciatic nerve release. Muscles, Ligaments and Tendons Journal. 2016;6(3):384–396.
Hernando MF, Cerezal L, Pérez-Carro L, Abascal F, Canga A. Deep gluteal syndrome: anatomy, imaging, and management of sciatic nerve entrapments in the subgluteal space. Skeletal Radiology. 2015;44(7):919–934.
Hutchins TA, Peckham M, Shah LM, et al. ACR Appropriateness Criteria: Low Back Pain, 2021 update. Journal of the American College of Radiology. 2021;18(11S)–S379.
Kizaki K, Uchida S, Shanmugaraj A, et al. Deep gluteal syndrome is defined as a non-discogenic sciatic nerve disorder with entrapment in the deep gluteal space: a systematic review. Knee Surgery, Sports Traumatology, Arthroscopy. 2020;28(10):3354–3364.
Lewis AM, Layzer R, Engstrom JW, Barbaro NM, Chin CT. Magnetic resonance neurography in extraspinal sciatica. Archives of Neurology. 2006;63(10):1469–1472.
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Stecco C. Functional Atlas of the Human Fascial System. Edinburgh: Elsevier; 2015.
Taneja AK, Bredella MA, Torriani M. Ischiofemoral impingement. Magnetic Resonance Imaging Clinics of North America. 2013;21(1):65–73.
Torriani M, Souto SCL, Thomas BJ, Ouellette H, Bredella MA. Ischiofemoral impingement syndrome: an entity with hip pain and abnormalities of the quadratus femoris muscle. American Journal of Roentgenology. 2009;193(1):186–190.
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DR. BRIAN ABELSON, DC. - The Author
Dr. Brian Abelson is a chiropractor, author, and educator with more than 30 years of clinical experience in musculoskeletal care, rehabilitation, and sports performance. His educational work focuses on musculoskeletal conditions, human movement, sports biomechanics, and evidence-informed approaches to treatment and rehabilitation.
He is the developer of Motion Specific Release (MSR) and Clinical Director of Kinetic Health in Calgary, Alberta, Canada.
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