Shoulder 101

Who knows what our rotator cuffs do? Or even better what is our shoulder complex?

Well here we go...

Our shoulder complex involves 4 main joints

Gleno-humeral joint - This joint is the glenoid fossa which is the " socket " part of the ball and socket joint. It also involves the humerus and the humeral head "the ball" of the joint.  It's not a very good ball and socket joint like the hip. The humerus head is much bigger then the glenoid fossa which is why we have a labrum to help deepen the "socket".

Acromio-clavicular joint - This is the "AC" joint. The acromion and clavicle (collar bone) make up this joint. This joint is commonly unstable due to the fact it has no muscles running over it to help stabilize it.

Sterno-clavicular joint- "SC" joint. This joint involves the sternum and clavicle (collar bone). This is an extremely stable joint due to the calcium deposits built up making it very resilient. When Packers QB Aaron Rodgers hurt is collar bone (clavicle) this last year this was a major concern.

Scapula-thoracic joint- This isn't like the other joints and some don't really consider it a joint.  But it involves the scapula (shoulder blade) and it sits over the thoracic rib cage. Scapula stability is extremely important for good shoulder health.

The Rotator Cuff

The muscle that make up the rotator cuff include the supraspinatus, infraspinatus, subscapularis, and teres minor. All 4 of these have one thing in common. They all insert into the head of the humerus. The supraspinatus is commonly injured due to where it's at. It runs right under the AC joint we talked about earlier and sits in the Subacromial space (Bottom of page has info on Subacromial space).

Wow, that was a lot of information... Anyways

The Job of the Rotator Cuff
The shoulder has 3 degrees of freedom. Meaning it can adduct and abduct, internal and external rotate, and flex and extend. Rotator cuff assists in those movements. Also the rotator cuff helps keep the humerus in its place. Especially durning overhead pressing. When we overhead press we need 4 things to happen.
- Scapula MUST rotate up words
- Rotator Cuff must contract and pull humeral head (ball) into glenoid fossa (socket)
- Rhomboids, traps, serratus anterior hold scapula against rib cage
- Humerus moves with good rotation

Weak rotator cuff and/or overactive deltoids can greatly increase injury . The deltoid is a bully muscle, it wants to pull the humerus out while the RC in trying to keep it in its place.

Weak rotator cuff + over active deltoid = increase in chances of injury.

Managing shoulder issues

Chances are you have some type of shoulder issue. With our horrid posture and our time sedentary increasing , and it not being a very stable joint to begin it's more likely then not. Also around our mid 30s we start to lose blood flow to our rotator cuff. But exercise can help ! Weird right?

Strengthen Rotator Cuff
Internal/external rotations - I put a towel in my clients armpits. When we do internal/external rotations with elbows tight to our sides we cut off the blood flow to the rotator cuff. Same thing if we raise our elbow parallel to our shoulder (90 degrees).

-If I'm pressing that day I do a primer set. I do 2 sets of 6-8 at various angles to get the rotator cuff firing and ready for action. No more, we want to prime it not weaken it.

-Use light weights for internal and external rotations. 5lb to 10lb max. Saw a guy use 20lb dumbbells. I don't care how big you think you are it's too much. Rubber tubbing or bands are great. **Be aware of resistance**

- Pull more then you push. 2-1 at least. 2 pulls 1 push. Strengthen traps, rhomboids, saratus anterior, lat. They all help stabilize the shoulder.

- If it hurts stop. I used to press 100lb dumbbells overhead and would leave the gym using my duffle bag as a sling. Not smart.

Any pain lifting or not being able to sleep on a certain side throughout the night because of shoulder pain you need to get it checked out by a medical professional.

Only medical professionals can diagnose. Don't be googling or using webMD thinking you can fix it yourself.

Extra information
Subacromial space- This is a space between the acromion and humerus. The two should be separated by 9mm-10mm. Once that space diminishes to less then 7mm we start to develop shoulder impingement. This puts stress on our supraspinatus (RC tendon), bicep tendon, Subacromial bursa. Usually this is the onset to more problems such as rotator cuff tears.


Adam KnutsonComment