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  • Low back pain
  • Mechanical low back pain
  • Lumbar sprain

  • M54.5 Low back pain
  • S33.5 Sprain of ligaments of lumbar spine


  • Quadratus lumborum muscle runs from the posterior superior iliac crest to the 12th rib
  • Can be unilateral or bilateral depending on mechanism of injury
  • Tenderness along origin, insertion, and line of muscle
  • Pain over muscle that radiates with trigger point pattern
  • May cause respiratory issues due to insertion of the muscle on the 12th rib
  • Most episodes are self-limiting

Essentials of Diagnosis

  • Diagnosis made by clinical examination
  • Use of treatment- or impairment-based classification system is useful to determine evidence-based treatment plan
  • Reproduction of symptoms in specific postures and activities
  • Rule out systemic disease (red and yellow flags)

General Considerations

  • Presentation may vary significantly based on anatomical structures and psychosocial factors
  • Often difficult to determine patho-anatomical cause of pain
  • Poor spinal alignment, scoliosis, and 12th-rib dysfunction can cause irritation of muscle by altering the length-tension ratio


  • Variable based on specific condition
  • May be specific to athletes, younger populations prone to extreme spinal movements

Signs and Symptoms

  • Pain lateral to lumbar spine between 12th rib and iliac crest that can be mechanically reproduced
  • Unilateral or bilateral pain along length of muscle or attachment
  • Lumbar segmental and 12th-rib hypomobility
  • Respiratory limitations
  • Difficulty with lumbar spine ROM
  • Often associated with poor body mechanics, core-muscle weakness, and postural deviations

Functional Implications

  • May be a leading cause of occupational disability
  • May impede ability to perform ADLs/IADLs
  • May impede participation in sports and other social activities

Possible Contributing Causes

  • Occupational factors
  • Congenital anomalies
  • Physical condition
  • Smoking
  • Obesity
  • Socio-economic factors
  • Psychosocial and behavioral factors
  • Postural changes
  • Weakness of core musculature
  • Tightness of hip flexors, external rotators, hamstrings

Differential Diagnosis

  • Facet joint dysfunction
  • Malignant spinal tumor or metastasis
  • Referred pain from visceral structures
  • Systemic auto-immune disease (rheumatoid arthritis, Reiter's syndrome)
  • Spondylosis
  • Spondylitis
  • Spondylolisthesis
  • Spinal misalignment
  • Sacral dysfunction
  • Erector spinae muscle strain
  • Myofascial pain syndrome
  • Herniated disc
  • 12th-rib fracture
  • 12th-rib dysfunction
  • Scoliosis
  • Respiratory problems
  • Leg-length discrepancy


  • Not necessary in most cases; only with persistent symptoms not responding to conservative management or if red/yellow flags are present
  • MRI helpful in diagnosis to visualize structure of muscle, compressed or inflamed nerve root, or disc pathology
  • X-ray/plain-film radiograph helps to assess alignment, fractures, stability (flexion/extension radiograph)
  • CT to ...

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