Understanding the Rotator Cuff


Acupuncturists often treat shoulder injuries that involve the rotator cuff. The rotator cuff is a group of muscles and tendons that help to raise and rotate the humerus, or upper arm bone, and stabilize the shoulder joint. Rotator cuff muscles and tendons keep the head of the humerus in the shoulder socket.  These muscles and tendons can become damaged by an acute injury or tear, repetitive overuse, aging, or even tendonitis. Acupuncture is a great way to alleviate pain and accelerate tissue repair in a rotator cuff injury.

The four muscles in the rotator cuff are the supraspinatus, infraspinatus, teres minor, and subscapularis. Understanding the actions of these muscles can help you understand what might be a cause of pain, and when to come in for an evaluation. The actions of the muscles in the rotator cuff are as follows:

  • Supraspinatus muscle. The supraspinatus lifts the arm bone above the head. It also helps to stabilize the shoulder, pulling the head of the humerus into the shoulder socket.
  • Infraspinatus muscle. The infraspinatus is the primary muscle that performs external rotation of the shoulder. It also stabilizes the shoulder joint and has a more minor function of pulling the arm backward.
  • Teres Minor muscle. The teres minor also helps to externally rotate the shoulder and stabilize the shoulder joint.
  • Subscapularis muscle. The subscapularis is the largest of the four muscles of the rotator cuff. It internally rotates the shoulder and helps to stabilize the shoulder joint. It also helps with arm adduction (movement of the arm toward the body’s midline).

If you’re experiencing pain when you lift, lower, or internally and externally rotate your arm, you may want to come in for a physical assessment, to determine if you may have a rotator cuff injury. Simple physical examination, palpation, and muscle testing can help your acupuncturist or other provider determine what’s injured and outline a treatment plan specific to your needs.