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