Shoulder Muscles: Anatomy, Function, and More

2022-05-21 15:48:48 By : Ms. Wendy Li

The shoulder muscles are responsible for maintaining the widest range of motion of any joint in your body. This flexibility is also what makes the shoulder prone to instability and injury.

Muscles, tendons, and ligaments combine to keep your arm bone in your shoulder socket. They also protect the main shoulder joint, the glenohumeral.

About eight shoulder muscles attach to the shoulder blade (scapula), upper arm (humerus), and collar bone (clavicle). Many other muscles play a part in stabilizing and guiding the shoulder and its movements.

There are about 20 muscles supporting the shoulder and allowing it to turn and rotate in many directions.

These are the largest shoulder muscles:

Another four muscles comprise the shoulder rotator cuff:

Here are the normal ranges of motion for the shoulder:

Each muscle and muscle group plays a role in supporting your shoulder and allowing the wide range of motion of your arms and shoulder.

The large shoulder muscles are responsible for most of the shoulder’s work.

The four muscles of your rotator cuff keep the head of your upper arm bone, the humerus, from popping out of the socket of the shoulder blade.

Because your shoulder is so flexible in all ranges of motion, it’s a common site of muscle injury and pain.

According to the American Academy of Orthopedic Surgeons, most shoulder injuries involve the muscles, ligaments, and tendon, not the bones.

Sometimes shoulder pain can be referred pain, which results from an injury to your neck or another place. Usually, this type of pain doesn’t get worse when you move your shoulder.

Common shoulder muscle injuries include:

Athletes are most at risk of shoulder muscle injuries. Older adults and those in occupations that involve repetitive or overhead motion or heavy lifting are also at risk.

A 2007 study found that shoulder pain was most prevalent in those age 55 to 64, affecting about 50 percent in that age group.

About 18 million Americans per year are affected by shoulder pain, according to a 2019 review. Rotator cuff tears are the most frequent cause.

Shoulder muscle injuries can result from:

Treatment for muscle shoulder pain and injuries depends on the cause and severity of the pain or injury.

Conservative treatment is often effective. This can include:

Acupuncture is reported to improve pain and function for 2 to 4 weeks. In some cases, surgery may be necessary.

It’s best to see a doctor if you have persistent or acute shoulder pain.

Sudden shoulder pain may be a sign of a heart attack, requiring emergency medical attention.

It’s important to get a diagnosis and begin treatment as soon as possible. “Working through” shoulder pain, or continuing a sport or training despite the pain can make the pain or injury worse.

The shoulder is a complex joint with many muscles that control the shoulder’s wide range of motion.

This freedom of movement makes the shoulder vulnerable to injury and pain.

Shoulder pain is common in athletes and the general population. Prompt treatment and rest are effective conservative treatments.

Last medically reviewed on April 16, 2020

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