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