Your infraspinatus is one of the four muscles that make up your rotator cuff. It plays a part in the movement and stability of your shoulder joint.
You put your shoulder muscles to the test in many sports like swimming, tennis, and baseball. But they're also key in daily activities like getting dressed or simply reaching for an item.
When you have infraspinatus pain, it can be difficult to carry out many of your regular activities.
What Is the Infraspinatus Muscle?
Your infraspinatus muscle is a thick triangular muscle located at the back of your shoulder. It’s attached to the top of your upper arm bone (humerus) and your shoulder blade (scapula).
The other rotator cuff muscles are the supraspinatus, subscapularis, and the teres minor. The main function of the four rotator cuff muscles is to stabilize the shoulder joint.
These muscles and other tissues make your shoulder the most mobile joint in your body. They allow it to move in many different directions.
Causes of Infraspinatus Pain
Infraspinatus pain ranges from mild strains to complete tears. Here are some of the causes of infraspinatus pain.
Infraspinatus Tears. Your infraspinatus can tear partially or completely. For younger people, rotator cuff muscle tears are mostly due to sports injuries. Rotator cuff injuries tend to increase with age. About 10% of people aged 20 and under have rotator cuff problems, compared to 62% of those aged 80 and older.
In older people, the tissues of your muscles may have weakened. This makes them more likely to tear from daily activities. Injuries like these can result from:
- Wear and tear
- Lack of use
- Repeated cortisone injections
It’s rare to completely tear your infraspinatus and keep your other three rotator cuff muscles intact. Experts say that there have only ever been two such cases. Both were due to injuries during contact football.
Pinched nerve. It’s very rare, but if your infraspinatus muscle has weakened enough, then the suprascapular nerve in your shoulder being can be compressed or pinched.
Tendinitis (also known as tendonitis). This is when your tendons are inflamed. It can also result in the tearing of tendon tissues. Up to a third of older adults with tendinitis of the rotator cuff have a tear.
Myofascial pain syndrome. This is a chronic pain condition that affects your muscles. The pain comes from trigger points or sensitive spots in a muscle. It can also cause referred pain. This is when you have pain in other parts of your body that seems unrelated.
Myofascial trigger points are a common cause of shoulder and arm pain. In a study of 126 patients, 31% had shoulder pain that originated from the infraspinatus muscle.
Symptoms of Infraspinatus Pain
You may notice one or more of these symptoms:
- Inability to use your shoulder
- Difficulty sleeping on your affected shoulder
- Limited range of motion
- A grinding or catching feeling when you move your shoulder
Diagnosis of Infraspinatus Pain
Your doctor will review your medical history and do a physical exam. They’ll ask you about your symptoms, recent injuries, and what kinds of sports or activities you do.
X-rays may be taken to exclude other problems. An ultrasound or magnetic resource imaging (MRI) scan may also be used to check the status of your injury. Some doctors may also use shoulder arthrography. Dye is injected into your joint so that it can be seen on x-rays.
Treatment of Infraspinatus Pain
For most people, nonsurgical treatment should help with infraspinatus pain. Surgery is usually recommended if:
- Your symptoms have lasted for 6 to 12 months
- You’re unable to use your shoulder
- The tear is more than 3 centimeters
- You have an acute injury
Nonsurgical treatments. If you have a mild injury, these treatments may be helpful:
- Rest: Take a break from your sports or activities.
- Ice it: Put some ice into a towel and hold it over your shoulder for 15 to 20 minutes.
- Stretching exercises: When your symptoms improve, you may begin some light exercises and stretches to strengthen your rotator cuff and muscles. An elastic band or light weights may be added as you regain your strength.
Check with your doctor before starting any exercise. Stop exercising if there’s any pain.
Light exercises. Here are some light exercises to try.
- Lean over, bending at your hips. You can use a tabletop for support.
- Slowly move your arm in all directions. You can use a light weight if desired.
- Do this for 1 to 2 minutes.
- Lie down with your knees bent.
- Clasp your hands straight out above your chest or hold onto something light like a cane or towel.
- Lower your arms downward, toward your head.
- Slowly lower them toward the floor.
- Slowly raise them back to the starting position.
These exercises should be done gently a few times a day.
Your doctor or physical therapist can recommend other exercises that can help you maintain the strength and flexibility of your joints. Recovery from a small tear or tendinitis can take between 2 and 4 weeks, or sometimes a few months.
Younger people are more likely to heal completely from rotator cuff injuries. 90% of people under the age of 40 with complete rotator cuff tears are often able to return to their previous level of function.