What are the possible causes of pelvic girdle pain located between the posterior iliac crest and the gluteal fold?

Causes of Pelvic Girdle Pain Between Posterior Iliac Crest and Gluteal Fold

Pelvic girdle pain in this specific anatomic location can present as either pregnancy-related pelvic girdle pain (affecting the sacroiliac joints and pubic symphysis) or as several distinct non-pregnancy-related conditions including Maigne's syndrome, iliolumbar ligament syndrome, L5/S1 facet syndrome, sacral insufficiency fractures, or sacroiliitis.

Pregnancy-Related Causes

Pelvic Girdle Pain (PGP)

The most common cause in pregnant or postpartum women is pelvic girdle pain, which affects nearly 20% of pregnancies 1. This musculoskeletal pain syndrome localizes between the posterior iliac crest and gluteal fold, originating from:

• Sacroiliac joint dysfunction due to pregnancy-induced ligamentous laxity 1
• Dynamic instability of the pelvic ring 2
• Softening of the symphysis pubis and sacroiliac joints leading to longer-term symphyseal or pelvic girdle pain 3

The underlying mechanism involves reduced load-bearing capacity from joint laxity that presents early in pregnancy and persists beyond 6 weeks postpartum 1. This reduction in ligament rigidity weakens joint stability, increasing demand on stabilizing muscles 1.

Risk factors include:

• Prior back pain before pregnancy
• Early symptom onset during pregnancy
• Higher pain severity during pregnancy
• Heavy occupational lifting (>20 times per week) 1

Sacroiliitis

Unilateral noninfectious sacroiliitis can cause severe postpartum pelvic girdle pain in this exact location 2. This typically resolves within 2 months with NSAIDs and physical therapy.

Non-Pregnancy-Related Causes

Maigne's Syndrome

Maigne's syndrome (D12/L1 dysfunction) presents as painful segmental vertebral dysfunction leading to cellulo-periosto-myalgic syndrome 4. Diagnosis requires:

• Rigorous segmental spinal examination
• Palpable changes in skin, muscle, and teno-periosteal tissue texture
• Pain reproduction with specific movements

Iliolumbar Ligament Syndrome

The iliolumbar ligament is a powerful stabilizing element of the lumbosacral hinge 4. Tensioning through repeated anteflexion and contralateral lateroflexion-rotation movements causes posteromedial iliac crest pain.

L5/S1 Facet Syndrome

Posterior inter-apophyseal joint L5-S1 pain presents with 4:

• More medial lumbosacral pain
• Pain accentuated on facet palpation
• Reproduction on combined heterolateral extension-rotation

Sacral Insufficiency Fractures

Insufficiency fractures of the sacrum occur at predictable sites in patients with osteoporosis, irradiated bone, or post-arthroplasty 5. These present with:

• Intractable lower back or pelvic pain
• Loss of mobility
• Symptom exacerbation with weight-bearing 5

Initial radiographs have low sensitivity (overlying bowel gas, soft tissue obscure findings) 5. MRI without contrast is the definitive diagnostic test when radiographs are negative, showing linear T1/T2 hypointense fracture lines with surrounding marrow edema 5, 6.

Other Structural Causes

• Ischiofemoral impingement with quadratus femoris compression 7
• Levator ani muscle injury from prior vaginal delivery 3
• Myofascial pain syndromes from multilayered muscular anatomy 8

Diagnostic Approach

For pregnancy-related pain:

1. Assess pain location (anterior vs. posterior pelvic ring)
2. Perform specific clinical tests for sacroiliac joint dysfunction
3. Evaluate for characteristic signs: difficulty walking, standing, sitting 9
4. Consider subgroups requiring different treatment approaches 9

For non-pregnancy-related pain:

1. Start with radiographs (AP pelvis, lateral lumbar spine) 5
2. If radiographs negative and high clinical suspicion: MRI without contrast is preferred 6
3. Perform segmental spinal examination for Maigne's syndrome 4
4. Assess facet tenderness and reproduction with combined movements 4

Treatment Priorities

For pregnancy-related PGP: Individualized physiotherapy focused on body awareness and specific functional training has good long-lasting effect 9. Severe cases (15-20% prevalence) can trigger sleep disturbance, impaired daily living, and depression, significantly affecting quality of life 1.

For non-pregnancy causes: Manual therapy centered on dorsolumbar or lumbosacral hinge as first-line, with rehabilitation of deep stabilizing muscles 4. Local infiltrations may complement physiotherapy.

Critical pitfall: Women often underreport pelvic girdle pain to prenatal providers, leading to insufficient clinical attention despite significant impact on quality of life and functional status 1. Persistent postpartum pain is more likely in those with prior back pain, early onset, and higher severity during pregnancy 1.