Pinching in the Shoulder? Understanding Impingement Syndrome
The shoulder is the most mobile joint in the human body and, as a result, it’s one of the most commonly injured.
While there are many types of shoulder injuries that can develop, one of the most prevalent conditions is “Subacromial Impingement Syndrome”, more commonly referred to as “shoulder impingement”.
What is shoulder impingement?
Shoulder impingement is a clinical syndrome characterized by a pinching-like pain that’s located in the soft tissues of the shoulder, most commonly in the front of the shoulder, and is most aggravated from elevation of the arm or from direct pressure on the shoulder (example; lying down/sleeping on the affected side).
There are two main types of shoulder impingement:
Primary Shoulder Impingement: this type of impingement is due to a physical narrowing of the subacromial space, which causes entrapment of the soft tissues and contributes to pain.
Secondary Shoulder Impingement: this type of impingement is due to mechanical dysfunctions, which means that the entrapment of soft tissues due to improper joint movement and compensatory patterns rather than being a structural problem.
We’ll touch a bit on primary shoulder impingement, but given the nature of what we do in the context of conservative care we’re going to focus more on the details surrounding secondary shoulder impingement as it’s extremely common and is better managed through conservative methods.
In order to truly understand the difference between these two it’s important to dive into the anatomy.
Shoulder Anatomy:
The subacromial space is located just underneath a portion of the scapula called the acromion process and just above the head of the humerus (the ball shaped portion of the upper arm).
If you’ll notice in the picture below, the supraspinatus tendon runs right through the subacromial space. It’s no surprise that one of the most commonly torn rotator cuff tendons is the supraspinatus tendon!
When it comes to primary shoulder impingement, common findings include degenerative changes that occur in any of the structures within the subacromial space (the acromion process, the subacromial bursa, the coracoacromial ligament, calcification of tendons, or even bony changes on the head of the humerus).
If this space is narrowed for any of the above reasons, when an individual goes to elevate their arm they’ll likely pinch the soft tissue structures thus causing the impingement.
Secondary impingement syndrome, on the other hand, is thought to be caused by mechanical dysfunction rather than degenerative changes.
In other words, it’s more about how we use our shoulder than it is about anything being inherently wrong with our shoulder.
To understand how our shoulder functions we need to understand the glenohumeral joint…
The Glenohumeral Joint:
We like to think of the glenohumeral joint as a “ball in a cup”, which helps us to visualize the way that the joint allows for movement.
We refer to the head of the humerus as the “ball” and the glenoid cavity (the lateral portion of the scapula) as the “cup”.
Here’s a photo to help demonstrate the anatomy:
When it comes to movement of the shoulder within the glenohumeral joint we like to keep it simple…
You need to keep the ball in the cup!
Injuries tend to occur when the ball moves around too much within the cup, or in some cases moves out of the cup.
In order to prevent injuries to the shoulder, especially secondary impingement syndrome, it’s important to be able to control both the ball and the cup to ensure that we can move them congruently and create stability throughout a given movement.
This relationship between the cup (scapula) and the ball (humeral head) is often referred to as scapulohumeral rhythm.
What is scapulohumeral rhythm?
Scapulohumeral rhythm refers to the relationship between the scapula and the humerus during any kind of movement of the shoulder, but most often during elevation of the arm.
Think of it this way - if the goal is to keep the ball centered in the cup we need to be able to move both the ball and the cup together.
Secondary impingement syndrome tends to occur when the ball moves up and forward in the cup, thus creating a functional narrowing of the subacromial space and impinging the soft tissues within it.
In other words, the cause of secondary impingement syndrome is abnormal scapulohumeral rhythm.
So if it’s a functional problem, how do we fix it?
Treatment for secondary impingement syndrome:
We’re firm believers that treatment is most successful when we take a well-rounded approach.
That means we have to provide both passively (manual therapy) and actively (rehab/corrective exercises) when approaching treatment for these types of cases…
Manual therapy for impingement syndrome:
Manual therapy can be extremely important when it comes to treating impingement syndrome.
There are 17 muscles that attach to the scapula and another 8 muscles that help to make up the shoulder complex!
Restrictions in any of these muscles can make it challenging for us to achieve certain ranges of motion, especially when reaching overhead.
In addition, joint restrictions within the thoracic and cervical spine regions can prevent proper motion and therefore limit overall mobility.
We address these by using various techniques including myofascial release, IASTM, cupping, and chiropractic adjustments.
These treatment methods help us to restore proper range of motion, which is the first step before we start focusing on improving the movement dysfunctions associated with the condition.
Rehab for impingement syndrome:
Once a proper range of motion has been established it’s important for us to train it!
As we mentioned earlier, one of the biggest contributing factors to impingement syndrome is scapulohumeral rhythm.
If the mechanism, or movement, that causes pain is elevating the arm we want to help our patients learn how to incorporate proper movement of the scapula and humerus in raising/elevating of the arm.
Here’s an example of an exercise we use, called the Serratus Anterior Wall Slide, that helps patients feel what it’s like to upwardly rotate their shoulder blade in order to keep congruency of the ball and cup while elevating the arm.
In addition, addressing the strength of the rotator cuff is extremely important.
The primary role of the rotator cuff is to create stability in the shoulder by holding the ball in the cup during various movements.
However, when we perform rotator cuff exercises it’s important to be aware of the position of the shoulder blade to make sure that we’re not placing unnecessary stress on the soft tissues and thus prolonging the pain of impingement syndrome.
Here’s a quick video that demonstrates how to put your shoulder in the “scapular plane” to ensure good positioning while strengthening the rotator cuff.
Lastly, over-activation of the upper trapezius commonly contributes to impingement syndrome. As a result, learning to activate and utilize the lower trapezius can help to prevent this common compensatory pattern. You can check that out below:
There you have it!
While impingement syndrome is extremely common, it doesn’t need to prevent you from being able to take part in the activities you enjoy.
Are you dealing with shoulder pain? We’re here to help! Follow the link below to book your appointment today.
