Buttock Pain Radiating Down the Leg – Is It a Disc?
It may well be superior cluneal nerve entrapment. About 27% of patients who still had pain after spine surgery turned out to have superior cluneal nerve (SCN) entrapment as the real cause, not a disc. Buttock pain that radiates down the leg is not always caused by a disc.
What Is Superior Cluneal Nerve Entrapment?
The Nerve Behind “Pseudo-Sciatica”
The superior cluneal nerve arises from the lower back (T12-L5) and supplies sensation to the skin over the upper buttock. As it crosses the iliac crest (the rim of the hip bone), it can be pinched in a narrow tunnel within the thoracolumbar fascia, causing pain.
Research shows that 47-84% of patients with superior cluneal nerve entrapment experience pain radiating down the leg.
How Is It Different From a Disc?
| Category | Superior Cluneal Nerve Entrapment | L4-L5 Disc |
|---|---|---|
| Pain Origin | Iliac crest area (below the flank); clear tender point | Central lower back; tender point unclear |
| One-Finger Test | Points precisely to a specific spot on the iliac crest (7-8 cm lateral) | Points to a broad area |
| Aggravating Posture | Leaning back, rotating, prolonged standing | Bending forward, sitting, coughing |
| Strength / Reflexes | Normal (purely sensory nerve) | May be weakened; reduced reflexes |
| SLR Test | Negative | Positive |
The One-Finger Test: The Simplest Way to Tell Them Apart
Identify the Painful Spot
When asked “Where does it hurt the most?”, the patient points to the exact spot with a single finger.
Press the Iliac Crest
If pressing the iliac crest (the upper edge of the hip bone), about 7-8 cm out to the side from the center of the lower back, produces severe tenderness, it indicates superior cluneal nerve entrapment.
Reproduce the Pain
Pressing the tender point reproduces the same buttock and leg pain the patient usually feels.
A Major Cause of Failed Back Surgery Syndrome
If buttock and leg pain persists even after back surgery, there is a good chance the problem was superior cluneal nerve entrapment all along, not a disc. A careful differential diagnosis is essential before any surgery.
Why the Superior Cluneal Nerve Gets Pinched
Stiff Thoracolumbar Fascia
As the fascia covering the back and lower back tightens, it narrows the passage the nerve travels through.
Adhesions at the Iliac Crest
Repetitive back movements or posture cause the nerve to stick to the surrounding tissue.
Stiff Thoracic Spine
When the upper spine is stiff, the lower back and buttock compensate, overloading the nerve.
Treating Superior Cluneal Nerve Entrapment
We release the site of nerve compression directly.
- Circulation HD:
- Release of thoracolumbar fascial adhesions at the iliac crest
- Improved circulation around the nerve
- Reduced nerve sensitivity
- Circulation PT:
- Restoring thoracic spine mobility
- Thoracolumbar fascia release exercises
- Posture correction
Frequently Asked Together
Want to Find the Exact Cause of Your Buttock Pain?
We evaluate both the disc and the peripheral nerves to reach an accurate diagnosis.
Book OnlineReferences
- Koes BW et al. Diagnosis and treatment of sciatica. BMJ. 2007;334(7607):1313-1317. PMID 17585160
- Boyajian-O’Neill LA et al. Diagnosis and management of piriformis syndrome: an osteopathic approach. J Am Osteopath Assoc. 2008;108(11):657-664.
- Laslett M. Evidence-based diagnosis and treatment of the painful sacroiliac joint. J Man Manip Ther. 2008;16(3):142-152. PMC2565072
- Cohen SP. Sacroiliac joint pain: a comprehensive review of anatomy, diagnosis, and treatment. Anesth Analg. 2005;101(5):1440-1453.