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Infraspinatus pathologies


Infraspinatus lesion


  • 3 muscles perform lateral rotation of the shoulder
    • Posterior deltoideus
    • Infraspinatus
    • Teres minor


  • Rotator cuff tendinopathy of the shoulder affects more than 80% of people over eighty years of age 1


  • The lesion can be identified at 3 locations:
    • Superficial part of the tenoperiostal insertion
    • Deep part of the tenoperiostal insertion
    • Body of the tendon
  • Palpation helps in identifying the correct location


  • Resisted lateral rotation – painful
  • Painful arc
    • Indicates superficial part of the tenoperiostal insertion is injured
  • Passive elevation – full movement, painful
    • Indicates the deep part of the tenoperiostal insertion is injured
  • Slow active de-elevation – painful
    • Indicates rotator cuff pathology 2
    • Palpation helps in identifying the correct location

Infraspinatus partial rupture


  • Typically, painful weakness of lateral rotation is associated with rupture of the infraspinatus


  • Resisted lateral rotation – Painful weakness

Infraspinatus complete rupture


  • Is either seen in isolation or in combination with a rupture (either complete or partial) of supraspinatus


  • Usually affects patients who are more than 50 years of age
  • Often seen after a fall on the shoulder or overexertion of the shoulder


  • The disorder is often asymptomatic
  • Is usually the result of wear of the shoulder and overactivity leading to repeated microtrauma
  • May be a result of a sudden trauma such as a fall or overload
  • After months, the pain and inflammation disappear although weakness can still be detected


  • The patient is unable to bring the arm into full lateral rotation
  • Visible atrophy might be detected at the infraspinatus fossa
  • Hornblower’s sign
    • Lifting the hand to the mouth is done by elevating the elbow high to compensate for lack of lateral rotation


  • Painful arc – both in active and passive movement
    • Caused by impinchment of the ruptured part of the tendon between the humeral head and acromion
  • Passive lateral rotation – full and painful
  • Resisted lateral rotation – weak

Additional functions

  • Acts together with subscapularis as a depressor of the humeral head during abduction so that there is more space for the movement avoiding subacromial impingement 3