Piriformis syndrome: a narrative review of the anatomy, diagnosis and treatment

Key points

1. 01Piriformis syndrome is sciatica caused by the piriformis muscle compressing the sciatic nerve, and it accounts for only about 6 to 8 percent of sciatica cases.
2. 02Diagnosis is complicated because buttock and low back pain have many overlapping causes, so it is often a diagnosis of exclusion.
3. 03Anatomical variation in how the sciatic nerve and piriformis relate, and where the piriformis tendon inserts, can confound examination and surgical findings.
4. 04Physical exam maneuvers such as FAIR, Beatty, and Pace are supportive but not definitive, with EMG and MRI used as adjuncts.
5. 05Treatment escalates from activity modification, stretching, and NSAIDs to local anesthetic, corticosteroid, or botulinum toxin injections, and finally surgery for refractory cases.
6. 06The broader term deep gluteal syndrome may better describe muscle and nerve mediated posterior pelvic girdle pain.

How it was conducted

Design

Narrative review of anatomy, diagnosis, and treatment

Sources searched

PubMed, CINAHL, and Embase

Study selection

71 of more than 8000 studies included by clinical relevance

Topics covered

Anatomy, history, physical examination, electrodiagnostics, imaging, myofascial mimics, and treatment

What they found

• Piriformis syndrome accounts for approximately 6 to 8 percent of sciatica cases, against a lifetime sciatica prevalence of 12 to 27 percent.
• Abnormal sciatic nerve and piriformis anatomy (Beaton and Anson six variants) is reported in approximately 17 to 19 percent of cadaver and MRI series, without a clear association to syndrome prevalence.
• Only approximately 54 percent of piriformis muscles show the traditional tendon insertion, and fusion with the obturator internus may confound internal rotation tests and operative findings.
• 71 of more than 8000 identified studies were included by clinical relevance.

Limitations

• This is a narrative review rather than a systematic review or meta-analysis, and study inclusion was based on clinical relevance rather than predefined quality criteria.
• No single physical examination test, EMG finding, or imaging result is diagnostic, so diagnosis remains one of exclusion.
• Anatomical variants common in the general population are not clearly tied to syndrome prevalence, leaving the link between anatomy and symptoms uncertain.
• Reported symptoms are non-specific and overlap with many other causes of buttock and low back pain.

Why it matters

For patients

If you have persistent buttock pain or sciatica, piriformis syndrome is one possible but uncommon cause that doctors usually consider only after ruling out more common spine and hip problems.

For clinicians

Treat piriformis syndrome as a diagnosis of exclusion, use exam tests and imaging as supportive rather than confirmatory, and escalate from conservative care to injections and only then surgery.

For readers

This review frames piriformis syndrome within the broader concept of deep gluteal syndrome and highlights how anatomical variation and clinical mimics complicate both diagnosis and treatment.