Infraspinatus

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

• 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

• 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

• 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