02/01/2026
Piriformis muscle issues can mimic sciatica, but true piriformis-related sciatic nerve compression is rare. Piriformis can mimic or contribute to sciatica, but true piriformis‑related sciatic nerve compression is less common than lumbar nerve‑root causes, which is why a careful exam is essential before blaming this muscle.
Anatomy and variants👇
The piriformis runs from the anterior sacrum to the greater trochanter, acting as an external rotator in neutral and an internal rotator at higher hip flexion angles.
In about 10–17% of people, part or all of the sciatic nerve passes through or above the piriformis rather than entirely below it, which can increase vulnerability to compression in that region.
How piriformis causes symptoms
Spasm, hypertrophy, or scarring of piriformis can compress the sciatic nerve where it exits the pelvis, producing buttock pain that may radiate down the posterior or lateral thigh and sometimes into the leg and foot.
This may present either as true nerve entrapment (with numbness, tingling, shooting pain, and possible weakness) or as referred pain from myofascial trigger points in a very tight muscle, often aggravated by sitting or hip rotation.
Differentiating from lumbar radiculopathy
Piriformis syndrome typically features focal buttock tenderness over the muscle, pain with FAIR/Freiberg tests, and symptoms that worsen with prolonged sitting or direct pressure, while lumbar radiculopathy more often shows dermatomal leg pain plus reflex, strength, or sensory changes from a compressed nerve root.
Imaging may show incidental lumbar changes, so clinicians often rely on history, exam, and response to targeted piriformis injection or treatment to confirm the diagnosis.
When to seek help
If simple stretching and activity modification do not ease symptoms, or if there is progressive weakness, numbness, or altered reflexes, assessment by a physio or spine specialist is important to rule out disc herniation and other serious causes.A careful exam is essential to diagnose the cause. The piriformis muscle runs from the sacrum to the greater trochanter and can compress the sciatic nerve, especially in anatomical variants. Symptoms include buttock pain radiating down the thigh, leg, and foot, often aggravated by sitting or hip rotation. Differentiating from lumbar radiculopathy is crucial, with piriformis syndrome featuring focal buttock tenderness and worsening symptoms with prolonged sitting. If conservative treatments fail, seek help from a physio or spine specialist to rule out serious causes
