Shoulder instability

Shoulder instability is tendency of the glenohumeral joint to sublux or dislocate due to loss of its normal functional or anatomical stabilizers:

  • static or anatomical:
    • articular surface 
    • labrum
    • glenohumeral ligaments
    • glenohumeral joint capsule
    • coroacoacromial arch
    • negative adhesive forces 
  • dynamic or functional:
    • rotator cuff
    • long head of biceps tendon

Shoulder instability can further be divided into:

As a result of this greater mobility, a number of secondary changes may become evident, including:

These changes, in turn, may lead to shoulder impingement.

Risk factors

Treatment and prognosis

In general, both anterior and posterior instability requires surgical repair and strengthening of the capsule.

Multi-directional instability is usually treated conservatively with rotator cuff strengthening exercises 2.

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Article information

rID: 2043
Section: Gamuts
Synonyms or Alternate Spellings:
  • Instability of the shoulder

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Cases and figures

  • Case 1 : anterior shoulder dislocation
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  • Case 2 : reverse Hill-Sachs and reverse Bankart
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  • Case 3 : bilateral shoulder instability
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  • Case 4: ALPSA, SLAP 2 tear, and GAGL lesions
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