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What are the internal rotators of the shoulder?

The internal rotators of the shoulder are muscles that help rotate the shoulder in. The shoulder is our most mobile joint. It is powered by many muscles. There is a group of four muscles called the rotator cuff. Some of those muscles help rotate the shoulder in (internal rotation) and out (external rotation) as well as muscles that help lift the arm. These rotator cuff muscles act in conjunction with the chest muscles (pectoralis) and shoulder muscles (deltoid, trapezius, serratus).

Rick Olderman
Physical Therapy Specialist

The internal rotators of the shoulder are muscles attaching to the humerus that internally rotate the arm:

  • latissimus dorsi: originates on the lower thoracic and lumbar vertebrae as well as iliac crest. It attaches to the inferior angle of the scapula as it travels up to insert on the humerus. Along with contributing to excessive internal rotation of the arm or scapular abduction, the latissimus dorsi also contributes to extension problems when tight or when the abdominals are weak.
  • pectoralis major: originates along the clavicle, down the sternum, and across the ribs and inserts into the humerus. This muscle can contribute to excessive internal rotation of the arm or scapular abduction.
  • teres major: originates on the scapula and inserts onto the humerus. When tight, this muscle contributes to scapular abduction and excessive internal rotation of the arm.
  • subscapularis: originates on the underside of the scapula and inserts onto the humerus. When tight, this muscle contributes to scapular abduction and excessive internal rotation of the arm.
Fixing You: Shoulder & Elbow Pain: Self-treatment for rotator cuff strain, shoulder impingement, tennis elbow, golfer's elbow, and other diagnoses.

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Fixing You: Shoulder & Elbow Pain: Self-treatment for rotator cuff strain, shoulder impingement, tennis elbow, golfer's elbow, and other diagnoses.

The shoulders are a floating system on the trunk, held in place and moved by muscular control. The foundation of shoulder movement is the shoulder blade which has precise resting and moving...

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.