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Infraspinatus

Contents

Anatomy

 

Infraspinatus - posterior view
Infraspinatus - posterolateral view
Infraspinatus - lateral view

General information

  • This section is strictly limited to anatomy, you might be looking for clinical relevant information which is found under the clinical chapters -- muscles section, click here to go to that page

Position

  • Superficial

Origin

  • Fossa infraspinata scapula

Insertion

  • Tuberculum majus humerus
    • Middle facet

Main function

  • Shoulder
    • Lateral rotation

Nerve innervation

  • Segmental
    • C5-C6
  • Peripheral
    • Suprascapular nerve

Arterial supply

  • Suprascapular artery
  • Scapular artery

Palpation of muscle belly

  • Patient position
    • Prone
  • Place the patient's arm outside of the edge of the treatment bench so that it is hanging down
  • Palpate inferiorly to the spina scapula until you feel the fossa infraspinata
  • Have the patient perform a lateral rotation of the shoulder while you feel for the contraction

Palpation of the distal tendon

  • Patient position
    • Prone
  • Place the patient's arm outside the edge of the treatment bench so that it is haging down
  • Palpate the top of tuberculum major and continue down inferiorly along the posterior margin og humerus
  • Ask the patient to perform lateral rotation of the arm in the shoulder joint while you feel for tension in the tendon

Strength test

  • Patient position
    • Sitting
  • This test also tests the strength of teres minor and not just the infraspinatus
  • Place the patient's arm at 90° abduction, the upper arm should be resting on the bench while the lower arm hangs outside the edge of the treatment bench
  • Place the arm in 70° lateral rotation
  • Place your one hand under the patient's elbow to stabilize the arm while your other hand is placed on the dorsal side of the lower arm
  • Give resistance in medial rotation so that the patient is giving force in direction of lateral rotation