Sign of the Buttock Test: Purpose, Procedure, Positive Findings & Clinical Significance
The Sign of the Buttock Test is an orthopedic physical examination used to distinguish pain and restricted hip movement caused by lumbar spine or hamstring problems from potentially serious conditions affecting the hip, pelvis, or deep gluteal region.
Originally described within Cyriax’s orthopedic examination approach, this test is particularly valuable when patients present with unexplained buttock pain, painful hip flexion, or symptoms resembling lumbar radiculopathy.
A positive Sign of the Buttock is considered a clinical red flag because it may indicate an underlying infection, fracture, tumor, or other significant pathology. However, the finding is not diagnostic by itself and must be interpreted alongside the patient’s medical history, other examination findings, and appropriate investigations.
What Is the Sign of the Buttock Test Used For?
The primary purpose of the Sign of the Buttock Test is to help differentiate musculoskeletal causes of restricted hip flexion from deeper pathological conditions involving structures around the hip and pelvis.
During a standard straight leg raise (SLR), the hamstring muscles and neural structures are placed under tension. Flexing the knee reduces this tension and typically allows greater hip flexion.
If hip flexion remains painful and substantially restricted despite knee flexion, the examiner should consider conditions that cannot be explained by hamstring tightness or neural tension alone.
The test may help identify patients requiring further evaluation for:
- Deep gluteal or pelvic infections: Including abscesses and osteomyelitis.
- Bone tumors or metastases: Affecting the pelvis, proximal femur, or surrounding tissues.
- Pelvic or sacral fractures: Particularly following trauma.
- Inflammatory or infectious disorders: Including septic arthritis and septic bursitis.
- Space-occupying lesions: Such as deep soft-tissue masses that interfere with hip movement.
The Sign of the Buttock Test is therefore primarily a screening examination, rather than a definitive diagnostic test for any individual disease.
How to Perform the Sign of the Buttock Test
The test is performed with the patient lying supine on an examination table. The examiner should explain the procedure and avoid forcing the joint beyond the patient’s tolerance.
Step-by-Step Procedure
- Patient positioning: Ask the patient to lie comfortably in the supine position, with both lower limbs extended.
- Perform a straight leg raise: Gently elevate the symptomatic lower limb while keeping the knee fully extended.
- Assess pain and restriction: Record the approximate angle at which hip flexion becomes painful or restricted. Note the location and character of the symptoms.
- Flex the patient’s knee: Bend the knee to reduce tension on the hamstrings and sciatic neural structures.
- Reassess passive hip flexion: Carefully attempt further hip flexion with the knee bent, observing the available range of motion and whether the patient’s pain changes.
- Compare the findings: Determine whether hip flexion improves substantially or remains unusually restricted and painful.
The essential comparison is between straight leg raising with the knee extended and passive hip flexion with the knee bent.
Classical descriptions emphasize that passive hip flexion may be more restricted or more painful than the straight leg raise in patients with a positive Sign of the Buttock.
Sign of the Buttock Test: Positive vs. Negative Results
Negative Sign of the Buttock Test
A negative result is generally observed when knee flexion allows a noticeable increase in passive hip flexion and reduces the previously experienced discomfort.
This finding suggests that hamstring tension or neural mechanosensitivity may contribute to the limitation.
Possible explanations include:
- Hamstring muscle tightness.
- Lumbar nerve root irritation.
- Sciatic neural tension.
- Other mechanical restrictions influenced by knee position.
However, a negative test does not completely exclude hip or pelvic pathology.
Positive Sign of the Buttock Test
A positive result occurs when passive hip flexion remains markedly painful and restricted despite flexing the knee. Classically, hip flexion with the knee bent may be more limited or painful than the initial straight leg raise.
This finding raises concern for pathology involving the hip, pelvis, or deep tissues of the buttock.
Potential causes include:
- Gluteal or ischiorectal abscess: A deep infection causing pain and restricted movement.
- Septic bursitis: Infection involving a bursa around the hip or buttock.
- Osteomyelitis: Infection affecting the proximal femur or pelvic bones.
- Neoplasms: Primary bone tumors, metastatic lesions, or soft-tissue masses.
- Pelvic fractures: Including sacral or other pelvic fractures.
- Septic arthritis: Joint infection associated with severe pain and restricted passive movement.
A positive test should prompt further clinical assessment rather than an immediate assumption that one of these conditions is present.
Why Is a Positive Sign of the Buttock Considered a Red Flag?
The clinical importance of the Sign of the Buttock Test lies in its potential to identify serious disorders that initially resemble ordinary mechanical back or hip pain.
Published case reports demonstrate this relevance.
A 2009 report in Physical Therapy described a patient with severe hip pain, night pain, and a positive Sign of the Buttock who was subsequently diagnosed with metastatic malignancy involving the proximal femur.
Another report described a positive sign in a patient with a previous total hip replacement, where further investigations identified a prosthetic joint infection.
A separate case demonstrated that an intermuscular lipoma compressing the sciatic nerve could also produce a positive finding.
These cases illustrate the importance of considering diagnoses beyond lumbar spine dysfunction. They do not, however, establish how accurately the test detects serious disease in the general population.
Red Flags Requiring Further Investigation
Additional concerning findings include:
- Persistent or worsening pain, especially at night.
- Fever or other symptoms suggesting infection.
- Unexplained weight loss or a history of cancer.
- Significant pain following trauma.
- Inability to bear weight.
- Severe restriction of multiple passive hip movements.
- A palpable mass or unexplained swelling.
Patients with a positive Sign of the Buttock and concerning associated symptoms may require urgent medical referral.
What Investigations Are Needed After a Positive Test?
Further assessment depends on the clinical presentation and suspected underlying condition.
A clinician may consider:
- Plain radiographs: To investigate suspected fractures, bone destruction, or other skeletal abnormalities.
- Magnetic resonance imaging (MRI): To evaluate deep soft-tissue lesions, bone marrow abnormalities, occult fractures, and suspected infection.
- Computed tomography (CT): To investigate certain pelvic or bony abnormalities and selected deep lesions.
- Laboratory investigations: Such as complete blood count, C-reactive protein, and erythrocyte sedimentation rate when infection or inflammatory disease is suspected.
A positive test alone does not automatically require MRI or CT. Imaging and referral decisions should be guided by the complete clinical assessment.
Clinical Significance and Limitations
The Sign of the Buttock Test is particularly useful in orthopedic, rehabilitation, and physical therapy examinations when clinicians need to differentiate lumbar spine-related symptoms from possible hip or pelvic pathology.
Its clinical value lies in recognizing an unexpected examination pattern that warrants further investigation.
Nevertheless, evidence specifically evaluating the test remains limited. Published reports largely include case studies and small case series, and robust sensitivity and specificity estimates have not been established.
For this reason, the test should be interpreted as part of a comprehensive clinical examination rather than used independently to confirm or exclude serious disease.
Frequently Asked Questions (FAQs)
1. What does a positive Sign of the Buttock Test indicate?
A positive result suggests that restricted hip flexion may be associated with pathology involving the hip, pelvis, or deep gluteal tissues rather than hamstring tension alone. Possible causes include infection, fracture, neoplasm, or another structural lesion.
2. How is the Sign of the Buttock Test performed?
The examiner performs a passive straight leg raise with the patient’s knee extended, then repeats passive hip flexion with the knee bent. Pain and movement restriction are compared between the two positions.
3. Is a positive Sign of the Buttock always serious?
Not necessarily. A positive result raises concern for significant underlying pathology but does not confirm it. The clinical importance depends on associated symptoms, physical examination findings, and medical history.
4. What is the difference between the Straight Leg Raise Test and the Sign of the Buttock Test?
The Straight Leg Raise Test primarily assesses symptoms associated with lumbosacral nerve root irritation and neural tension.
The Sign of the Buttock Test compares hip flexion with the knee straight and bent to help identify restrictions that cannot be explained by hamstring or neural tension alone.
5. Can the Sign of the Buttock Test detect a tumor?
The test cannot diagnose a tumor. However, a positive result may raise suspicion of a pelvic, proximal femoral, or deep soft-tissue mass, particularly when accompanied by unexplained pain or other concerning symptoms.
6. Does a positive Sign of the Buttock require an MRI?
Not every positive result requires MRI. Advanced imaging may be appropriate when the clinician suspects infection, malignancy, an occult fracture, or a deep soft-tissue abnormality.
7. Is the Sign of the Buttock Test reliable?
The test has been described in orthopedic examination literature and supported by clinical case reports. However, high-quality diagnostic accuracy studies are limited, and its sensitivity and specificity are not well established.
Conclusion
The Sign of the Buttock Test is a useful clinical screening examination for patients presenting with painful or restricted hip flexion, buttock pain, or symptoms resembling lumbar spine pathology.
A negative finding, characterized by improved hip flexion after knee flexion, suggests a contribution from hamstring or neural tension. Conversely, a positive result, in which painful hip flexion remains markedly restricted, raises concern for deeper hip, pelvic, or gluteal pathology.
Because some associated conditions require prompt treatment, clinicians should recognize this finding and combine it with a comprehensive physical examination and appropriate medical investigations.
References
- Orthofixar. Sign of the Buttock Test. Clinical examination, technique, interpretation, and red flags. Updated February 2026.
https://orthofixar.com/special-test/sign-of-the-buttock-test/ - Greenwood MJ, Erhard RE, Jones DL. Differential diagnosis of the hip vs. lumbar spine: five case reports. Journal of Orthopaedic & Sports Physical Therapy. 1998;27(4):308–315.
https://pubmed.ncbi.nlm.nih.gov/9549715/ - VanWye WR. Patient screening by a physical therapist for nonmusculoskeletal hip pain. Physical Therapy. 2009;89(3):248–256.
https://pubmed.ncbi.nlm.nih.gov/19168712/ - Burns SA, Burshteyn M, Mintken PE. Sign of the buttock following total hip arthroplasty. Journal of Orthopaedic & Sports Physical Therapy. 2010;40(6):377.
https://pubmed.ncbi.nlm.nih.gov/20511697/ - Kim JY, Koo HJ, Park GY, Choi Y. Lipoma Compressing the Sciatic Nerve in a Patient With Suspicious Central Post-stroke Pain. Annals of Rehabilitation Medicine. 2017;41(3):488–492.
https://pubmed.ncbi.nlm.nih.gov/28758088/ - Das JM, Dua A, Nadi M. Straight Leg Raise Test (Lasegue Sign). StatPearls. NCBI Bookshelf.
https://www.ncbi.nlm.nih.gov/book