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Condition/Disorder Synonyms


  • Low back pain

  • Mechanical low back pain

  • Lumbar sprain


ICD-9-CM Codes


  • 724.2 Lumbago

  • 847.2 Sprain of lumbar


ICD-10-CM Codes


  • M54.5 Low back pain

  • S33.5 Sprain of ligaments of lumbar spine


Preferred Practice Pattern1


Key Features




  • 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




  • May be specific to athletes, younger populations prone to extreme spinal movements


Clinical Findings


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


Means of Confirmation or Diagnosis




  • Not necessary in most cases; only with persistent symptoms not responding to conservative management or if red/yellow flags ...

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