Shoulder Impingement Syndrome is a very common cause of shoulder pain. Fortunately, it’s a problem that is well treatable.
There is no reason why you shouldn’t be able to make a full recovery. But to be able to treat it the right way, you’ll have to know the cause. There are several different causes and treatment options for an impinged shoulder.
So I decided to write an overview of the possible causes and treatments for shoulder impingement syndrome.
The anatomy of your shoulder
To be able to understand the what the shoulder impingement syndrome is and what it’s possible causes are, you need to know a little bit about the anatomy of your shoulder joint.
The shoulder joint is formed by 3 bones:
- Your humerus (arm bone)
- Your scapula (shoulder blade)
- Your clavicle (collarbone)
The humerus and scapula don’t really fit together. The head of your humerus is much bigger than the surface of the scapula it attaches to. This makes it an unstable joint by definition.
The reason for this is that your body sacrificed stability for mobility.
Your shoulder joint is the most mobile joint in your body.
To compensate for this instability there are several shoulder muscles that try to keep the joint together. These muscles are known as the rotator cuff muscles.
There are 4 rotator cuff muscles:
All these muscles run from the scapula and attach to the head of the humerus. Two of these are important in understanding the shoulder impingement syndrome. This is because your supraspinatus and infraspinatus run between your humerus and scapula through the subacromial space.
For protection, they are covered by your subdeltoid bursa. Your bursa works like a little airbag. When the pressure on one of these muscles increases, your bursa fills with water to protect the muscles.
What is the shoulder impingement syndrome?
There are basically 5 structures that can cause compression:
- Supraspinatus muscle
- Infraspinatus muscle
- Shoulder bursitis
- Head of the humerus making contact with scapula
Your supraspinatus or infraspinatus muscle (tendon) can be either strained or ruptured. When it’s strained it swells up. When this happens, the muscle takes up more space. So when you lift up your arm, it becomes squeezed between your humerus and scapula. This movement causes a sharp pain.
The second way your rotator muscle can cause problems is when it’s completely ruptured. When this happens it doesn’t use any space. This causes the humerus and scapula to come closer together. Which causes your humerus to hit the top of your scapula, causing a lot of pain and limited mobility. This requires surgery to reattach the tendon to muscle.
When there is a calcification in your supraspinatus muscle present it can become compressed inside your shoulder joint when lifting your arm. However, this doesn’t always have to be the case. It really depends on the position and size of the calcification as well as the available space inside your shoulder joint. This can be aggravated more by have a slouched posture.
Also, a shoulder bursitis causes shoulder impingement syndrome. When you have a bursitis the bursa is inflamed and full of water. This takes up all the space in your shoulder joint. When this happens you will usually be unable to move your arm at all and have constant pain, even in rest.
The last possibility is that the space between your shoulder blade and humerus head is insufficient. When this happens your humeral head runs into your shoulder blade when lifting your arm. There are multiple possible reasons for this. Typically these problems are usually caused by overloading the muscles of your shoulder or after a fall.
What are the symptoms of the shoulder impingement syndrome?
The shoulder impingement syndrome symptoms are different for each of the different causes.
When the supraspinatus muscle is involved you can tell it by the following symptoms:
- The first symptom is a pain at the front side of your shoulder.
- The second symptom is that this pain radiates down your arm, at the front side. Usually, this radiation stops halfway down your forearm.
- The third shoulder impingement symptom is a pain when lifting your arm above 80 degrees sideways.
- The final symptom for an impingement syndrome is pain during outer rotation of your arm. This pain is especially prominent when you try to grab something that lies next to you.
Also, to lie on your shoulder is painful.
When your infraspinatus muscle is involved, one of the above symptoms is different:
Now the pain radiates at the outer side of your arm all the way to your hand.
With calcification your shoulder feels more stiff than painful when lifting your arm. Forcing the movement can cause pain.
If you’ve ruptured your supraspinatus muscle you’re suddenly in a lot of pain, right after injury. Also, you are unable to lift up your arm, without engaging larger muscles and moving the whole shoulder girdle. Surgery will be required in this circumstance.
Lastly, when you have a shoulder bursitis, you’re in a lot of pain and totally unable to lift your arm at all in any direction. You’ll even have a lot of pain when you’re not moving your arm.
The symptoms, together with the cause will give you a good idea on what the problem is.
There are also a few tests that I can perform in clinic to determine if you really have a shoulder impingement syndrome. If you would like to book an appointment please click here or if you have any questions feel free to email me on firstname.lastname@example.org