Infraspinatus Muscle Anatomy
& Exercises 101: The Rotator Cuff

This infraspinatus muscle anatomy guide contains all you'll want to know about this back muscle; from its functions to exercises and more.

This small muscle is an essential part of the rotator cuff...

...The rotator cuff, as an entity, enables the incredibly useful action of omni-directional rotation (rotary movement in all directions) of the upper arm via the shoulder joint. These muscles may also be considered back muscles, as this is where they are located, generally speaking.

The infraspinatus muscle is attached from the inner side of the scapula (shoulder blade) to the top of the upper arm bone just under the supraspinatus. Its main action is outward rotation of the shoulder.

You can use the glossary resource at the bottom of the page to find definitions of terminology within this muscle anatomy guide.

Infraspinatus Muscle Anatomy

Infraspinatus Muscle


  • Origin
    • Infraspinous Fossa of the Medial Scapula
  • Insertion
    • Middle Facet of the Posterior Surface of the Greater Tubercle of the Humerus
  • Function
    • External Shoulder Rotation
    • Transverse Shoulder Abduction
    • Transverse Shoulder Extension
    • Posterior Shoulder Stability

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Infraspinatus Muscle Exercises

Exercises. Below is a list of the exercises that most directly workout this rotator cuff muscle.

  • Cable External Shoulder Rotations (Seated or Standing)
  • Dumbbell External Shoulder Rotations (Seated, Lying, or Standing)
  • Machine External Shoulder Rotations

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Related Muscles. The three other rotator cuff muscles are listed below:

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  • External Shoulder Rotation. Turning the upper arm toward the outside.
  • Posterior Shoulder Stability. Maintaining the secureness and balance of the rear shoulder.
  • Transverse Shoulder Abduction. Moving the upper arm outward and away from the chest, on a horizontal plane; typically done in a bent over position like the bent over lat raise exercise.
  • Transverse Shoulder Extension. Pulling the upper arm backward, away from the chest and with the elbows out and pointed to the rear.


  • Greater Tubercle. The large bony protrusion on the lateral (outer) side of upper humerus; specifically, it is on the outside of the head of the humerus.
  • Humerus. Upper arm bone.
  • Infraspinous Fossa. The slightly concave depression, which covers a large area on the rear surface of the scapula.
  • Middle Facet. The greater tubercle contains three flat impressions, to which a different muscle is attached. The second highest impression is the middle facet, which attaches to the infraspinatus.
  • Posterior. Back, or rear.
  • Rotator Cuff. A complex shoulder structure comprised of muscles and tendons, which enables omnidirectional rotary movement (movement in all directions) via the ball-and-socket shoulder joint.
  • Scapula. Shoulder blade.

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