What is the Rotator Cuff?

what is the rotator cuff

The rotator cuff is a group of four muscles in your shoulder: namely, the Supraspinatus, Infraspinatus, Teres minor, and Subscapularis (or SITS, if you want a helpful mnemonic). They encapsulate the shoulder joint, called the glenohumeral joint, which attaches your upper arm to your scapula. 

The rotator cuff has 2 primary jobs: 1) stabilize the shoulder and 2) assist movement. As a ball-and-socket joint, the shoulder is particularly mobile – yet particularly unstable. The rotator cuff muscles help stabilize this important joint through abduction, internal rotation and external rotation. 

Let’s take a look at the role each muscle plays in performing these duties.

The Muscles of the Rotator Cuff

rotator cuff muscles
Source: wikipedia

The supraspinatus muscle is the primary muscle that assists abduction, or moving your arm out and away from your body (as if you’re about to make a snow angel). To perform that motion, you use the supraspinatus muscle in the first 15 degrees of abduction before other shoulder muscles like the deltoid and trapezius take over.

Unfortunately, the supraspinatus muscle is the most commonly injured of the rotator cuff muscle. This is partially due to its location and susceptibility to wear and tear. 

The infraspinatus and teres minor muscles work together to rotate the shoulder outward in a hinge-like motion called external rotation. These two, relatively small muscles are located on the back of your shoulder blade. They attach to the humerus (your upper arm bone), rotating it outward when contracted. 

The largest and 4th rotator cuff muscle, the subscapularis, rotates the arm inward for internal rotation (the reverse of external rotation). This muscle is also the strongest of the 4, with the ability to generate as much force as the other 3 rotator cuff muscles combined. 

All four of these muscles work together to help stabilize the head of the humerus within the shoulder socket. Straining or tearing any of the rotator cuff muscles can lead to shoulder instability, weakness, and pain.

Rotator Cuff Injuries

A rotator cuff tear is a remarkably common shoulder injury, affecting over 2 million people annually. The tear is technically a separation of tendon from bone, often beginning with the supraspinatus tendon and then spreading to the rest of the rotator cuff. 

If the tear affects one portion of the cuff but doesn’t entirely sever it, the injury is considered a “partial” rotator cuff tear, as opposed to a “full thickness” rotator cuff tear. 

What Causes a Rotator Cuff Tear? 

There are two main causes of rotator cuff tears: 1) acute injury or 2) degeneration

The rotator cuff may tear under sudden stress, such as an athletic injury or trauma. In most cases, however, the tear develops slowly from gradual overuse or general wear and tear. 

Rotator cuff tears are much more common among adults over the age of 40. That’s because degenerative conditions such as muscle weakness, lack of blood supply, and bone spurs can all contribute to a gradual tear. 

Identifying and Diagnosing a Rotator Cuff Tear

Because rotator cuff tears are often slow to develop, initially you may experience only minor pain from overhead movements. But as the injury progresses, pain and weakness will become more prominent. 

Along with other measures, PTs use a few special tests to help diagnose a rotator cuff tear. These simple movements can indicate weakness, pain, or compromise in each rotator cuff muscle. 

The most salient symptom of any rotator cuff tear is shoulder pain while at rest, especially when lying on the affected shoulder. Other symptoms include pain or weakness when lifting, lowering, or rotating the arm. Some people experience a popping or clicking sensation when moving their arm. 

Either way, an injured rotator cuff will impede basic tasks, such as dressing or reaching to fix your hair.

Can the Rotator Cuff Heal Itself?

Unfortunately, a rotator cuff cannot heal itself; the injured tendon will not reattach to the bone on its own. Even after rotator cuff repair surgery, the strength of your shoulder will be compromised. That’s why early detection of a rotator cuff tear is key to minimizing damage and restoring function.

Although a rotator cuff tear will not heal on its own, research shows that non-surgical treatments can bring considerable relief to a rotator cuff tear, whether large or small.  

Treating a Torn Rotator Cuff

Obviously, rest is the primary non-surgical treatment for a torn rotator cuff. You will also need to considerably modify daily activities to avoid worsening the tear. 

Meanwhile, you can relieve the pain with ice, anti-inflammatory medications, or even steroids. Depending on the severity of the tear, some light exercise will help ameliorate pain and improve range of motion.

Rotator Cuff Repair Surgery

The majority of rotator cuff tears don’t require surgery. However, if your shoulder pain and weakness persist for several months despite careful treatment, you may need to undergo a surgical rotator cuff repair. 

There are three different methods for a rotator cuff repair:

1) open repair through a traditional, surgical incision at the shoulder

2) arthroscopic repair through a camera and miniature surgical instruments

3) mini-open repair, which combines arthroscopy with open surgery through a considerably small incision.

Each of these 3 surgical procedures has its own advantages and disadvantages. Your doctor may recommend one based on your injury and other factors. 

After surgery, your particular recovery process will depend on your age, overall health, and post-operative care.

Physical Therapy for Rotator Cuff Tear

No matter the size or seriousness of your rotator cuff tear, the road to recovery will include physical therapy rehabilitation.

In fact, physical therapy may help you avoid surgery altogether. By gently strengthening the untorn portion of your rotator cuff, you’ll restore some function and strength in your shoulder without undergoing surgery. Check out these simple, non-surgical rotator cuff exercises to relieve shoulder pain and improve mobility. 

But if your case does require surgery, you might have to wait a couple months after the operation to begin physical therapy treatment. You’ll need to protect the repair and avoid moving it while it heals.

Regardless, it’s best to consult with your PT and orthopedic physician for your treatment options. You may be able to find relief with PT alone, but if the injury is severe and surgery is recommended, you’re better off going ahead with the surgery.

Don’t Delay Treatment

Whether it’s physical therapy or surgical repair, seeking immediate treatment will give your rotator cuff the best shot at a full or near-full recovery. 

By contrast, putting off vital intervention will lead to further degeneration and potentially a larger tear. So work with your PT to strengthen the muscle fibers you still have. Whether or not you get surgery, Physical Therapy will improve your strength and reduce the severity of your injury. 

Tim Fraticelli, DPT Physical Therapist

Tim Fraticelli is a Physical Therapist, Certified Financial Planner™ and founder of PTProgress.com. He loves to teach PTs and OTs ways to save time and money in and out of the clinic, especially when it comes to documentation or continuing education. Follow him on YouTube for weekly videos on ways to improve your financial health.