The Rotator Cuff: Going Deeper: The Shoulder Girdle: Introduction

Role: Guide Actions of Arm Bone

The muscles of the rotator cuff guide the actions of the arm bone itself, while other larger muscles control the actions of the shoulder as a whole, with both arm bone and shoulder blade functioning as a unit. – Doug Keller

Subscapularis

  • Located on underside of scapula
  • Internally rotates the humerus
  • Tightness can limit external rotation of shoulder
  • The infraspinatus and teres minor form a “force couple” with the subscapularis to stabilize humerus in the joint
  • Upper side arm in Gomukhasana (Cow Face Pose) stretches the subscap
  • Acts as a stabilizer in holding poses such as Warrior 2

Supraspinatus

  • Originates in supraspinous fossa of scapula and inserts on greater tuberosity of the humerus
  • Initiates abduction of the arm
  • When taking the arm out to the side, during the first 15 degrees of lifting, we are contracting the supraspinatus; after that, it becomes a synergist of the deltoid for abduction (Ray Long MD)
  • The rotator cuff muscle that is most frequently torn (Ray Long MD)
  • Drawing the arm across the chest as in Garudasana (Eagle Pose) stretches the supraspinatus

Infraspinatus

  • The inraspinatus and teres minor insert onto back of greater tuberosity of humerus
  • Antagonist of subscapularis
  • Externally rotates humerus
  • The infraspinatus and teres minor form a “force couple” with the subscapularis to stabilize humerus in the joint
  • Reverse Namaste stretches the infraspinatus and teres minor muscles

Teres Minor

  • The inraspinatus and teres minor insert onto back of greater tuberosity of humerus
  • Externally rotates humerus but the infraspinatus is the stronger external rotator
  • The infraspinatus and teres minor form a “force couple” with the subscapularis to stabilize humerus in the joint
  • Lower side arm in Gomukhasana (Cow Face Pose) stretches the infraspinatus and teres minor muscles