Scapula Dyskinesia

The shoulder blade or scapula (2 scapulae) is crucial to how the shoulder functions, but also plays a large role in our upper body posture and can contribute to neck pain.  Triangular in shape, the scapula lies against the back of the rib cage.  Anteriorly it is connected to the chest via the collar bone (clavicle). 

 Pictures from: http://en.wikipedia.org/wiki/Scapula  

 

The scapula can move in a number of planes allowing several different movements to occur:

·         Elevation and depression

·         Upward and downward rotation

·         Protraction and retraction

·         Anterior and posterior tilt

Picture from: http://www.xsens.com/images/stories/scapula_rotation.jpg  

 

Getting your head around these movements is important for assessing scapula posture at rest and under load.  Muscle balance around the shoulder blade, neck and thoracic spine effects the position of the scapula and thus the stability and mobility of the neck and shoulder.  17 different muscles attach to the scapula. 

1. Serratus Anterior
2. Supraspinatus
3. Subscapularis
4. Trapezius
5. Teres Major
6. Teres Minor
7. Triceps Brachii long head
8. Biceps Brachii
9. Rhomboid Major
10. Rhomboid Minor
11. Coracobrachialis
12. Omohyoid inferior belly
13. Lattisimus Dorsi
14. Deltoid
15. Levator Scapula
16. Infraspinatus
17. Pectoralis Minor

Having an appropriate group of muscles working around the scapula (force couple) enables the scapula to work effectively as a base for the shoulder to move from and limits excess strain on the neck.  An imbalance in these muscles often results in what is called scapula dyskinesis (a fancy name for a movement disorder of the shoulder blade).      

In the diagram below you can see the different pull of 3 muscles (lower traps, upper traps and serratus anterior) all attaching to the scapula.  This force couple is particularly important when the shoulder is moving and we see what is called scapulohumeral rhythm. 

Picture from: http://nateregensburg.blogspot.com.au/2010/12/increasing-upper-body-strength-by.html   

Today I particularly want to discuss the neutral position of the scapula when the arm is in neutral (by the side of the body).  You might ask why is that important when you don’t play sport with your arm held by your side?  We do, however, spend a lot of our day with arm/s close to our body – walking, working at a desk or computer, eating, sitting on the couch.  For athletes it’s important that they don’t have poor posture during the day, leading to muscle imbalance, before going to training or competition, as this can adversely affect their performance or cause injury     

The neutral position of the scapula is flat against the ribcage with no rotation, tilt or elevation present.   The medial border of the scapula should be vertical.    Landmarks commonly used to assess scapula position are the spine of the scapula at T3 and the inferior angle of the scapula level with T7.  This is not entirely accurate as the size of each scapula will vary depending on the size of the person. 

Modified picture from: http://en.wikipedia.org/wiki/File:Orientation.PNG

 

Commonly patients with neck and/or shoulder pain present to physiotherapy and winging scapula/e are noted on assessment.  Winging occurs when the medial (inside) border of the scapula lifts away from the ribcage.  We should consider 2 types and causes of winging:

1) Winging of the entire medial border – due to weakness in serratus anterior

2) Winging of the inferior angle of the scapula – due to weakness in lower trapezius

If you suspect weakness in serratus anterior it’s important to rule out a long thoracic nerve palsy.  This can occur from trauma or infection or be insidious.  It requires a longer period of rehab and referral for medical opinion. 

Both types of winging and other forms of scapula dyskinesia (e.g. downwardly rotated scapula at rest) require postural correction and exercise prescription. 

Far too often physios (and pilates instructors and other health professionals), cue people to pull their shoulder blades back and down to set a neutral scapula position.  The problem here is not all shoulder blades are sitting forward and up, so this cue to set the scapula is not going to correct all scapulae properly.  Having a generalised, non specific cue like “draw down and back” leads to problems. 

Remembering that the role of lower traps is to depress and upwardly rotate the scapula we need to have more specific cues for patients with scapula dyskinesia.

Highlighted below is the right levator scapulae muscle.  On the left, the overlying trapezius muscle is still present.  Levator scapulae elelvates the scapula, but also downwardly rotates the scapula (blue arrow) in combination with other muscles such as pec minor. This downward rotation is counterbalanced by the fibres of upper traps and lower traps (green arrow) with lower traps also balancing the elevation of the scapula.  The force couple between these muscles needs to work to enable a neutral scapula position.   

Modified picture from: http://en.wikipedia.org/wiki/Levator_scapulae_muscle

There’s no recipe I can give you for treating scapula dyskinesia and each patient will respond differently to different cues.  If you take the time to assess the scapula position properly and then base your postural cueing and exercise program on this I don’t think you can go wrong.  Tactile (palpation, sweep tapping, taping)  and visual (computer biofeedback) also help heaps!!

LB

 

Some other reading you might be interested in: Link here to a recent paper from scapula guru Ben Kibler and colleagues: Clinical implications of scapular dyskinesis in shoulder  injury: the 2013 consensus statement from the ‘scapular summit ’http://bjsm.bmj.com/content/47/14/877.full.pdf+html

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

program on this I don’t think you