Shoulder Pain: The 4 Main Culprits

Let's not make shoulder pain more complicated than it already is, we can break it down to 4 main culprits.

In order to discuss and understand the most common causes of shoulder pain it’s important to have a basic understanding of how your shoulder joint both looks and functions. 

If you can stick with me through this brief anatomy lesson I promise you’ll be able to get to the bottom of your shoulder pain (and it will all make more sense!)

Your shoulder joint is considered a “ball-and-socket” joint made up of three bones; the humerus (upper arm), the scapula (shoulder blade) and the clavicle (collar bone). The end of your upper arm bone is shaped like a small ball that fits right into the socket of the shoulder blade. Unlike the relatively deep ball-and-socket joint of your hip, the shoulder joint is actually quite shallow and is more often compared to a “golf ball sitting on top of a tee” (see picture below). 

At any given time there’s only 20-30% of the golf ball surface in contact with the tee. This means you have the ability to achieve a lot of movement at this joint. But with great movement, comes great responsibility. The better you are at keeping the golf ball as close as possible to the center of the tee during arm movements (ie. pushing, pulling, reaching overhead etc) the greater your function will be and the less likely you are to be predisposed to possible injuries.

Surprisingly, your entire arm and shoulder complex is actually only attached to the rest of your body via the collar bone attaching to the front of your chest (sternum). 

This means that your shoulder relies heavily on three important levels to keep it strong and stable. Let’s have a look at these shall we…

At any point in time there is roughly only 20-30% of the golf ball surface (upper arm) in contact with the tee (shoulder socket)

Level 1: The Skeleton

There are 3 key factors you’re born with that will impact how stable your shoulder joint is:

• Shoulder socket
• The labrum
• Joint capsule

No two skeletons are alike. Some people will naturally be born with deeper or more shallow shoulder sockets which will influence how stable or mobile their shoulders will be.

The thick piece of tissue known as “the labrum” helps create an extra rim around the shoulder socket which expands and deepens the tee, allowing a greater percentage of the golf ball to remain in contact.

The golf ball is also held in place by a joint capsule made up of small-but-strong ligaments. This capsule wraps around the entire joint like a tight-fitting glove and forms an air-tight hold.

Level 2: The Stabilisers

The next layer of support involves a group of four muscles known as the “rotator cuff”:

• Supraspinatus
• Infraspinatus
• Teres Major
• Subscapularis

I’m sure you’ve heard of these muscles any time you’ve had a shoulder complaint in the past and seen an allied health professional (think about the rubber band exercises you’ve traditionally been given).

They are the primary stabilisers of the shoulder joint ie. their job is to keep the golf ball sitting nicely on top of the tee during movements.

The small strong shoulder capsule & the rotator cuff muscles provide the primary stability of the shoulder joint.

Level 3: The Movers

If you keep zooming out you can see the much larger muscle groups of the chest, back and shoulders. As the name suggests, these muscles focus on movement of your arm (shoulder) and should not be relied upon as primary stabilisers.

Unfortunately if our rotator cuff muscles aren’t doing their job we will often rely on these muscles to pick up the slack. Because their primary job is not to worry about keeping the golf ball in the center of the tee, we’re more likely to end up with some level of irritation or discomfort in the shoulder (eventually). 

If you become a regular reader of these blogs you’ll start to notice a trend that a lot of aches and pains develop when we ask parts of our body to take on jobs they’re not really designed for. Whilst doing the best they can, they’ll eventually trigger some level of pain or discomfort which is their way of asking for help!

Alright we’ve survived the brief anatomy lesson. 

Now you’re all experts let’s talk about the four main culprits of shoulder pain: the stiff, the weak, the loose and the imposter!

Let's meet the 4 main categories of shoulder pain...

The "Stiff" Shoulder:

There is a difference between having a tight shoulder and a genuine “stiff” shoulder. The most common cause of genuine stiffness is adhesive capsulitis (aka frozen shoulder). It involves the development of pain, stiffness and loss of normal range of motion.

Think back to the anatomy lesson above, frozen shoulder affects level 1 of the joint – the shoulder capsule. Remember the capsule is the tight-fitting glove of strong ligaments surrounding the joint, so we can see how progressive restriction of this tissue affects how well we can move your shoulder joint.

In another blog we’ll discuss how frozen shoulder is actually diagnosed, what the treatment options are and what the latest evidence tells us about recovering from this condition.

The "Weak" Shoulder:

This category covers many often heard diagnoses such as rotator cuff tears, tendinopathies, shoulder impingement, sub-acromial bursitis or sub-acromial pain syndrome.

I personally avoid using the word “weak” and prefer to use the phrase “unprepared for certain activities” but unfortunately that seems a bit lengthy for a category title. In essence, the most common causes of shoulder pain (conditions listed above) come under this category and are related to some sort of strength or capacity shortfall.

It’s important to know that every body will have some sort of imbalance or “weakness” in their upper body and most of you won’t experience any pain at all! Often there is a pretty simple reason why people start to develop these kinds of aches and pains:

• You’ve been too inactive, for far too long OR
• You’ve done too much activity, far too quickly

This idea of “load management” is one of the most valuable lessons you can understand and I’m sure we’ll have another blog designated to this entire concept very soon. Essentially when aches and pains occur this means that our activities (demands) have exceeded our capacity (tissue tolerance). 

Example: If you haven’t trained at all and you run a marathon on the weekend, your body will let you know exactly how far outside the comfort zone you’ve pushed. Your calves, knees and hips will all be sending messages to the brain asking you to very kindly not do that again without preparing them in advance!

Now whilst it’s actually quite difficult to pin-point a specific tissue that’s causing your pain, the beauty of it is that we don’t actually need to! Regardless of the diagnosis the treatment plan framework will look almost identical for most conditions. So why over-complicate it?

In another blog we’ll discuss the five strategies to overcoming overload-related pain and rebuilding your shoulder strength through movement.


The "Loose" Shoulder:

There are two reasons somebody would fall under this category:

• They are born with either naturally shallow shoulder sockets or lax ligaments
• They’ve recently suffered a traumatic dislocation and now have short-term laxity

People who come across as extremely flexible or even “double-jointed” would fall under this category. In the case of traumatic injuries, the ball has been forced either entirely or partially out of the shoulder socket. We’ve pushed so far outside the comfort zone that the tissues have been stressed, stretched and even damaged. 

Depending on the extent of the traumatic injury, you’ll either require surgical intervention or allow the tissues to heal naturally. During this healing process you’ll have short-term reduced stability within the joint. 

Another unfortunate process that can occur during a dislocation is that you may get a bone fracture. To repeat the golf-ball-sitting-on-a-tee analogy, this means you might fracture either the golf ball itself, or the tee which it’s placed on. So not only will there be stretching and laxity in the shoulder capsule, but you might lose some of the smooth surface area between the golf ball and the tee. 

We’ll look deeper at shoulder instability in another blog and discuss the phases of rehab required to return to your chosen activities or sports.

The "Imposter" Syndrome:

And finally we’ve reached our final culprit: “The Imposter”. Why the imposter you ask? Because whilst you might be experiencing pain or symptoms in the shoulder region, the cause has nothing to do with the shoulder itself!

There are 3 main categories of referred shoulder pain:

• Somatic
• Visceral
• Malignant

I know those words mean absolutely nothing most-likely so let’s make some sense of them.

“Somatic” is referring to other parts of your musculoskeletal system causing pain in your shoulder. The most common regions include your neck, upper back and other surrounding muscles in the area.

“Visceral” is just a fancy word for “organ”. Yep. Some organs such as the gall bladder, spleen and heart all have the ability to refer pain into your shoulder.

“Malignant” is associated with various forms of cancers or tumours.

This section is not meant to be alarming, whilst they are possible, they are drastically less likely than the previous 3 categories. In another blog we’ll discuss referred shoulder pain and describe in more detail how it’s even possible and how to determine whether pain is coming from the shoulder itself as opposed to these structures.

Currently struggling with shoulder pain and left wondering which category you're in or how you’re going to deal with it?

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