Test your rotator cuff knowledge with a 1-question quiz.
Question: What is the rotator cuff?
A) Protective armor surrounding the rib cage
B) 4 shoulder muscles
C) The biggest ligament in the shoulder
D) Another term for “rotary cup”
Unless you’re an armadillo or a medieval knight, you don’t have protective armor around your rib cage.
The rotator cuff isn’t a ligament. And “rotary cup” isn’t a real thing, despite what the older gentleman at the gym tells you when describing his shoulder surgery.
The answer is B.
The rotator cuff is a key group of shoulder muscles.
There’s a lot of fear and misunderstanding surrounding the rotator cuff. A lot of people don’t know what it is or why it’s important. And a torn rotator cuff is considered a death knell for normal shoulder use…until you read the research.
Here’s what you need to know about the rotator cuff:
The Muscles
These 4 muscles make up the rotator cuff:
The subscapularis muscle sits in the front of the shoulder, attaching to the front of the humerus. This view (below) shows the right shoulder from the front. The subscapularis is considered the anterior rotator cuff.
The supraspinatus muscle sits atop the shoulder blade and attaches to the top of the humerus. Shoulder impingement usually involves supraspinatus irritation.
The infraspinatus muscle starts on the back of the shoulder blade and attaches to the back of the humerus. This view shows the back of the right shoulder.
Last but not least, the teres minor muscle sits right below the infraspinatus and also stretches from the shoulder blade to the humerus. The supraspinatus, infraspinatus and teres minor muscles form the posterior rotator cuff.
What Does The Rotator Cuff Do?
The rotator cuff’s main job is dynamic stability. The shoulder joint is a ball-and-socket. Big ball. Small socket. Like a golf ball on a tee.
Due to it’s structure, the shoulder is the most mobile joint in the body. It’s also the least stable…and easiest to dislocate.
The rotator cuff dynamically stabilizes the shoulder to keep the ball in the socket.
Rotator cuff muscles also rotate the shoulder. The posterior rotator cuff performs external rotation – imagine pulling your driver’s seatbelt into place with your right hand.
The subscapularis handles internal rotation – picture a forehand tennis shot from Roger Federer.
How Does It Get Injured?
Rotator cuff injuries occur two ways.
Overuse
Non-traumatic rotator cuff injuries result from overhead overuse. Think of a painter, car mechanic, or factory worker who’s elevating their arms for hours every day. Repetitive, overhead activities can cause shoulder impingement, a precursor to rotator cuff injury.
Trauma
Falls, car accidents and weightlifting mishaps can injure the rotator cuff.
Are Rotator Cuff Tears Painful?
A torn rotator cuff sounds pretty scary. Shockingly, most rotator cuff tears don’t cause pain! Some research shows a 2:1 ratio of pain-free RTC tears to painful RTC tears! (Minagawa 2013)
MRIs are the most popular imaging tool to identify rotator cuff tears. The imaging technology is amazing; MRIs show soft tissue (muscles, tendons, ligaments) in high definition. Unfortunately, MRI findings don’t correlate well with shoulder pain.
Rotator cuff tears respond similarly to conservative treatment vs. shoulder surgery (Ryosa 2017). So experts advocate taking the conservative route first.
In short, physical therapy is the best first-line treatment for rotator cuff injuries.
How Do I Keep My Rotator Cuff Healthy?
There are several non-modifiable risk factors for rotator cuff injury; you can’t choose parents with healthy shoulders or arrest the aging process.
But here are 3 steps you can take to keep your shoulders healthy:
1) Don’t smoke: Cigarette use increases the risk of rotator cuff tears.
2) Keep a healthy body weight: Metabolic diseases like diabetes, high cholesterol, and obesity are linked to rotator cuff tears.
3) Strengthen your shoulders: Shoulder weakness is connected to rotator cuff injuries. These two simple exercises (below) target the rotator cuff through resisted shoulder rotation. You only need a towel and a doorway.
1) Shoulder Internal Rotation Isometrics
Gently push into the towel. Hold 5 seconds, then relax. Repeat 10 times. This exercise strengthens the subscapularis.
2) Shoulder External Rotation Isometrics
Gently push outward into the towel. Hold 5 seconds, then relax. Repeat 10 times. This exercise strengthens the supraspinatus, infraspinatus and teres minor.
Learn More
For more rotator cuff resources, check out:
7 Exercises to Avoid with Rotator Cuff Injury
How to Relieve Shoulder Impingement
8 Infraspinatus Exercises to Build a Strong Rotator Cuff
Readers: Have you dealt with shoulder pain? A rotator cuff injury? Did you decide to go the conservative or surgical route? Share your experience in the comments.
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