Does the sciatic nerve affect any bursas?

Sciatic Nerve and Bursa Relationships

Yes, the sciatic nerve has clinically significant anatomical relationships with bursae, most notably the trochanteric bursa at the hip, where greater trochanter bursitis can mimic or coexist with sciatic nerve pathology.

Direct Anatomical Relationship

The sciatic nerve does not directly innervate any bursae, but it has important spatial relationships with several bursae that create diagnostic and clinical challenges:

Trochanteric Bursa

• The trochanteric bursa lies in close proximity to the sciatic nerve's course as it exits the pelvis and passes through the gluteal region 1
• Greater trochanter bursitis (GTB) frequently mimics sciatica, with pain radiating to the posterolateral thigh and paresthesias in the legs—symptoms nearly identical to sciatic nerve compression 2, 3
• In a study of 657 patients referred for sciatica, 10.95% were actually suffering from GTB rather than true sciatic pathology, and an additional 2.74% had both conditions coexisting 2

Clinical Significance of the Relationship

The proximity of the sciatic nerve to the trochanteric bursa creates a diagnostic trap where GTB is frequently misdiagnosed as sciatica:

• GTB predominantly affects middle-aged women (mean age 60 years), with a female-to-male ratio of approximately 7:1 2
• Patients with GTB present with tenderness over the iliotibial tract and pain radiating posterolaterally down the thigh, closely mimicking L5-S1 radiculopathy 3
• The key distinguishing feature is tenderness over the peritrochanteric area on physical examination 3

Popliteal Region Considerations

While not a direct bursa-nerve relationship, the sciatic nerve's terminal branches have proximity to popliteal bursae:

• Baker's cysts (popliteal cysts) represent fluid accumulation in the gastrocnemius or semimembranosus bursae and can communicate with the joint space 4
• The sciatic nerve divides into tibial and common peroneal branches in the popliteal region, creating potential for compression by large or ruptured popliteal cysts 4

Diagnostic Approach

When evaluating suspected sciatica, clinicians must systematically assess for trochanteric bursitis to avoid misdiagnosis:

• Palpate the peritrochanteric area for focal tenderness (positive in GTB, negative in pure sciatica) 2, 3
• Assess for pain with hip external rotation and abduction (provocative for GTB) 3
• Consider diagnostic/therapeutic injection of the trochanteric bursa with local anesthetic and corticosteroid—dramatic pain relief confirms GTB 2, 3
• Ultrasound can confirm trochanteric bursa inflammation when diagnosis is uncertain 2

Treatment Implications

Recognition of the bursa-nerve relationship prevents unnecessary imaging and inappropriate treatment:

• Peritrochanteric infiltration with glucocorticoids mixed with 2% lidocaine provides long-term symptom relief in GTB patients 3
• In one study, patients with chronic low back pain who received trochanteric bursa injections had significantly better outcomes (p < 0.0005) than those who did not 3
• Failure to diagnose GTB leads to unnecessary spinal imaging, inappropriate back-focused treatments, and prolonged patient suffering 2

Common Pitfall

The most critical pitfall is assuming all posterolateral thigh pain represents true sciatica without examining for trochanteric tenderness—this leads to misdiagnosis in approximately 11% of patients referred for sciatica 2. Always palpate the greater trochanter region in patients presenting with "sciatica" symptoms, particularly in middle-aged women with chronic symptoms 2, 3.