Anatomy Lesson: The Shoulder/ Scapula

A wise man once said, "If you're feeling like a pimp, go and brush your shoulders off." 

Well I'm definitely feeling like a pimp, so I'm gonna go ahead and talk about the shoulder, because there isn't anything more sexy than shoulders.  Or if your like me the soldiers; I suck at pronouncing the difference between the two - I can't be the only one.

We've gotten good response from our anatomy lesson series, so let's get one step further and put the shoulder under the microscope.  If you've missed any of the other lessons, check them out

Ankle/Foot
Knee
Hip/Pelvis
Spine

The shoulder is a real interesting joint, it's very similar to the hip except without the amount of muscle mass and stability.  The shoulder needs a tremendous amount of mobility and stability - just think about throwing a baseball.  In fact during an overhead throw the shoulder goes through 7,000 - 9,000 degrees of rotation per second, that's the fastest motion the human body produces.  The shoulder goes through crazy ranges of motion and bears the brunt of extreme forces and stresses.  It is a truly incredible joint considering all it does and the unique actions it is involved in.  It's like the J-Timberlake of the body - J-Timberlake rocks the music, acting, dancing, and comedy world; while the shoulder rocks the mobility, stability, and modeling world.

The Shoulder

Bones

   - Humerus - Upper Arm
   - Clavicle - Collar Bone
   - Scapula - Shoulder Blade

While the shoulder is often thought of as a singular joint or location it's not.  Four different joints are actually connected or related to the shoulder

   - Glenhumeral Joint - This is the traditional shoulder joint, where the humerus fits into the socket of the scapula.
   - Acromioclavicular (AC) Joint - This is where the clavicle meets the acromion on the scapula.
   - Sternoclavicular (SC) Joint - This is where the clavicle connects to the sternum.
   - Scapulothroacic Joint - This is called a false joint because it's not really a true joint, it's a location where the scapula glides against the rib cage.  It's important to mention because the surrounding muscles work to keep the scapula lined up during shoulder movements.

Ligaments - Remember ligaments are soft tissue structures that connect bones to bone, are a main source of stability for the shoulder.  Here's a quick run down of important ligaments in the shoulder

 - Acromioclavicular
 - Coracoclavicular
 - Sternoclavicular
 - Interclavicular
 - Costoclavicular
 - Coracoacromial
 - Coracohumeral
 - Glenohumeral

Muscles and Actions - There are a ton of muscles that impact the function and movement of the shoulder.  It's really a busy area in terms of small, intricate muscles involved and due to the wide range of scapular, cervical, and clavicular involvement on the shoulder.

   - Deltoid - Deltoid is the traditional big shoulder muscle.  The deltoid is often broken into 3 groups: Anterior Delt, Lateral Delt, and Rear Delt.   Each distinct group is contributes more or less to certain movements, but in general the delts play a big role in abduction, rotation, flexion, and extension.

   - Rotator Cuff Complex - An easy way to remember the rotator cuff is SITS

Supraspinatus - Primary responsibility involves concentric abduction of the humerus

Infraspinatus - Primary action involves external rotation of the humerus

Teres Minor -  Primary role is external rotation of the humerus

Subscapularis - Primary action is internal rotation of the humerus.

While each specific muscle of the rotator cuff complex has a different primary function, it is key to know that they all work together it keep the humeral head centered in the glenoid fossa.  They are not primary movers, they are stabilizers and their most important job is to keep the humeral head centered.

Scapula Muscles - Assist in scapular stabilization and active movement of the scapula.

   Trapezius - Three groups of the Trapezius
       - Upper Traps - Elevation, Upward Rotation
       - Mid Traps - Retraction, Upward Rotation
       - Lower Traps - Retraction, Upward Rotation, Depression
   Levator Scapulae - Elevation, Downward Rotation
   Rhomboid Group - Retract, Elevation and Downward Rotation
   Serratus Anterior - Protraction and Upward Rotation
   Pec Minor - Downward Rotation, Depression, Retraction

Other Humeral Muscles - These help attach the humerus to the trunk
   Lats
   Pec Major
   Biceps Brachii

Problems

The shoulder joint is one of the most injured joint in the body.  According to Sipes et al, 30% of athletes suffer a shoulder injury during their career.  Overhead sports such as baseball, volleyball, QBs in football, softball, and throwers in track and field know all to well how stressful overhead movements can be on the shoulder and the importance of maintaining health in the joint.  Remember the shoulder goes through 7,000 - 9,000 degrees of rotation per second during overhead movements!

Also many lifters experience problems performing different vertical pushes and pulls ie overhead press, snatch, jerk, pull-up, etc.  A great deal of ROM, strength, and stability is need for these movements, and many lack those qualities.  Let's go ahead a take a peek at a few common problem areas.

Impingements - An impingement is basically a compression of the tendons of the rotator cuff in the glenohumeral joint, usually in the subacromial space.  It can become chronic and cause serious inflammation of the tendons and limit ROM, strength, stability, and cause pain.

First off not everybody's shoulder is created equally.  Some people have naturally poorly structured shoulder joints for overhead sports and lifts.  A big component of this is the shape of the acromion process. 

Type 1 - Flat, this shape is built for overhead actions, and the risk of impingement cuasing pain is minimal.
Type 2 - Curved, this shape needs to have some precaution to take.  Due to the curve, subacromial space is reduced and this can increase risk of impingement.
Type 3 - Beaked, sorry but people with this acromial shape are unfortunately not meant to perform overhead actions.  The subacromial space is greatly reduced and overhead movements can often lead to problems.

Shoulder impingement's are pretty dang common, most people have an impingement of some degree, but whether that impingement is painful or not depends a lot on the the shape of the acromion, soft tissue health, stability, mobility, and strength of the the shoulder joints.

Overall shoulder impingement's are a lot more advanced and in-depth than what we just explained.  There are many different factors that come into play, but that is a basic overview.  Watch Dr. Evan Osar talk a little bit more about impingement's and keeping the humeral head centered.

AC Joint - An AC injury is commonly known as a shoulder separation.  Recall the AC joint is the connection of the collar bone to the top of the shoulder (acromion).  An injury usually occurs to the AC joint after a brunt force or falling on the shoulder.  But tendonitis and tendonosis can also be common in the AC due to lots of overhead movements.  I've separated both AC joints and let me tell you they aren't fun and they can take a long time to fully heal.  Some bad AC separations require surgery, and you may recall top QB Sam Bradford and Matthew Stafford have both surgery on their AC joints.

Superior Labrum, Anterior to Posterior Tears (SLAP) - The labrum is a fibrocartilaginous tissue around the rim of the glenoid fossa and helps keep the humerus supported in the joint.  A SLAP tear refers to an injury to the labrum of the shoulder, and SLAP specifically points to the upper part of the labrum running from front to back.  These kind of tears usually occur from falling on an outstretched arm, repetitive OH movements, and from lots of throwing.  You can often tell a SLAP tear because you'll hear a clicking sound in the shoulder or during certain ranges of motion the shoulder will "catch".

Glenohumeral Internal Rotation Deficit (GIRD) - GIRD is a deficit when comparing internal rotation of the dominant shoulder to non-dominant shoulder.  The difference between the two should not exceed 15 degrees.  On the same note is measurement of total range of motion in terms of the sum of IR and ER.  Comparing dominant arm and non-dominant arm, the difference should not be more than 5 degrees.  The differences in IR and total rotation are often seen in overhead athletes.  So many repetitions of overhead movements put a lot of stress on the posterior components of the shoulder to decelerate the arm.  This causes some inflammation, gunky tissue, and those muscles and tissues to become overworked, and this tightness in the posterior shoulder decreases IR.  If someone presents more than 15 degrees of difference of IR and 5 degrees of total rotation, this increases risk of shoulder injuries.  Now if GIRD is found, don't be in a rush to go ahead and stretch into internal rotation.  There are many other factors that contribute to GIRD such as scapular mobility/stability, labrum health, capsular health, rib position, soft tissue quality, and cuff strength.

Fixes

Mobility - Let's clear the air right now, most shoulder problems result from scapular dysfunction.  The scapula doesn't get the love it deserves considering it is half of the glenohumeral joint. 
Consider this, the head of humerus should move in conjunction with scapula.  Think about a golf ball on a tee.  If you were to grab the ball and tee together and move it around, the ball would stay centered on the tee and the two would move in conjunction.  If you have an immobile scapula, then the humeral head compensates and loses centration of the glenoid fossa and this is when problems occur.  The scapula needs to be able to move freely and have full range of motion to support the movement of the humerus. 

A way to attack this is to work on thoracic spine mobility.  Remember the scapula is essentially a free floating bone with numerous muscular attachments.  Working on thoracic mobility also targets scapular mobility due to the high amounts of connection and "team-work" between the two.

Balance - Many problems at the shoulder occur to imbalances in training and everyday life.  We've talked about improving the balance between pull vs push exercises and getting that ratio more to 2:1 in favor of pulls.  But not as well known is improving the balance of upward rotation vs downward rotation. 

This imbalance can lead to scapular depression, which is very common with many athlete these days.
This imbalance leads to the shoulder blades being drawn back and down.  Take a look at your collar bone in the mirror.  It should have an upward angle going from medial to lateral.  When the downward rotators take over it pulls your shoulders down, and your collar bones will sit more flat or parallel to the ground.  Doing loads of bench, row, deads, and getting cued to death with "shoulders back and down!" leads to the downward rotators winning the balance battle of the scapula.  So it's time to give the upward rotators some love.  Target the serratus, upper traps, and lower traps (upward rotators) with face pulls, no money, overhead shrugs, and prone wall slides.

Soft Tissue Work - Soft tissue work is especially important for shoulder health.  With 17 different muscles impacting shoulder position and function, there can be a mess of problems.  Tissues can get beat up and dense so using some soft tissue work, especially on the pec minor, posterior rotator cuff, lats, levator scapulae, and cervical spine/1st spine.  Doing soft tissue on these areas can instantly lead to lead to ROM increases and can make stability and strength exercises more effective.

Rotator Cuff – While we talked about how most rotator cuff problems probably are better treated with scapular mobility and stability work, but you still need proper strength, endurance, and timing in your rotator cuff complex. 

You need a strong posterior cuff (infraspinatus and teres minor) for decelerating the rapid speeds of internal rotation, but you also need a very strong anterior cuff (subscapularis) to both depress the humeral head during overhead work and prevent anterior translation of that head.  Now don't get carried away with and start killing Internal and External rotations all day, the Cuff also needs good timing, and remember it's most important job is to keep the humeral head centered in the glenoid fossa.  Some favorites include some distraction or proprioception work, and for endurance farmer's walks and suitcase carry's are awesome.

Breathing Patterns – Breathing patterns are soooo important and it can greatly effect shoulder health.  Diaphragmatic breathers have much better shoulder function than those who breath into their chests, and a big reason for this is rib and torso positioning.  Remember, the shoulder does connect to the ribcage and breathing patterns can strongly influence position and function of the many of muscles of the collar bone, scapula, and ribs and all of these can play a role in shoulder health.

Alrighty hope you enjoyed!  Also remember to sign-up for BBA updates to stay on top of great articles like this one being posted!  Also like our Facebook page and join in some discussion!  Until next time Go Get Em!


More Sources - These guys below are the shoulder gurus in the sports performance industry.  Eric Cressey coaches mainly baseball players and his experience with overhead athletes is tremendous.  Mike Reinold was a PT for the Red Sox's and he's worked with Cressey on a number of awesome products.  Check them out for real great information on all things shoulder.

Eric Cressey
Mike Reinold