Brachialgia - Scapular Dynamics and the Brachial Plexus

Why doesn't the pain respond when the movement is better?

Brachialgia is a very common clinical problem seen by physical therapists.  Clearly this can be caused by abnormal movement control in the shoulder girdle which can naturally influence the brachial plexus.  Therapy often involves improving motor control but sometimes there is an obstacle - the pain.

This article focuses on a key issue when the brachial plexus is part of the problem. 

At the heart of the problem is this popular line of reasoning:

“Movement dysfunction is causing the pain”

“Fix the dysfunction and the neural problem will go away.”

“Let’s lengthen upper traps, levator scapulae and pectoralis minor so the shoulder can get back to its normal position.”

“Lower trapezius and serratus anterior need to be more active so the shoulder doesn’t move up and rotate forward  so much too.  And that’s also great because it opens the subacromial space.”

Clearly, this may help some patients, but what about the patient whose pain is an obstacle to this approach?  The therapist can be left stymied by the lack of progress because it just doesn’t make sense.

Well, it makes much more sense if we include neurodynamics.

The problem lies in not realizing that scapular depression, retraction and posterior rotation all reduce the space around the brachial plexus.  

So it is logical that, if the plexus is sensitive or compressed, those movements actually compress it more.

Take a look at my ultrasound video of the plexus between the clavicle and first rib.  The shoulder starts in the normal relaxed position and the scapula moves into the posterior rotated position with contraction of serratus anterior.

Notice that the distance between the first rib and clavicle is much less in the posterior rotated position and the plexus is compressed.

So how do we resolve the conflict between the musculoskeletal and neural systems?

The solution is that we can direct treatment at reducing pressure on the plexus in the acute phase then change the focus to the musculoskeletal when the plexus settles down.

The first phase will therefore involve scapular movements for the neurodynamics. 

The second phase makes use of movements for motor control that were planned at the beginning.

This produces different emphasis at different times in the rehab process and it depends on the balance of the mechanisms at that time.