United Brachial Plexus Network, Inc.

"Good question, and one we are often asked.

The shoulder joint is a ball-and-socket joint that is able to move freely in
any direction when the ball is within the socket. The joint itself is composed
of the head of the humerus (the "ball") fitting into the scapula (the
"socket"). In the normal situation, the scapula is stabilized by the serratus
anterior muscle against the chest wall. This allows the arm to move against a
fixed base, which is very efficient.

If the scapula becomes unstable, such as with an injury to the nerve of the
serratus anterior muscle (the long thoracic nerve), then winging occurs. This
is due to the weight of the humerus pushing the unstable scapula away from the
chest wall.

In the case of an unstable scapula where the humerus is no longer in the
socket, there is no weight pushing the scapula away from the chest wall, and
the winging disappears. Therefore, in kids where winging is prominent, the arm
is usually not dislocated; conversely, lack of winging usually means the arm
is dislocated.

The most common reason for dislocation is failure of formation of both the
ball and the socket components of the shoulder joint, as occurs with brachial
plexus injury. The reasons that BPIs cause failure of formation of the joint
are probably due to lack of normal nerve supply to the joint as it develops,
and also to the abnormal movements of the shoulder muscles themselves.

An associated phenomenon is that sometimes dislocations are not visible when
contractures are present. Then, after the Mod Quad surgery to relieve the
contractures allows more visible movement, the dislocation is unmasked.
However, the surgery itself does not cause the dislocaiton, it merely allows
more movements that uncover the pre-existing dislocaiton. This is shown with
X-rays and MRI studies."

R. Nath
rnath@bcmtmc.edu

Thanks Francine. Dr. Nath is always so helpful.

I was not aware that the long thoracic nerve was injured in BPI patients, weakening the Serratus Anterior muscle. No one ever talks about this muscle, just the infra-/supraspinatus, deltoid, bicep. It would make sense because the nerve is derived from the C5, C6, & C7 nerve roots.

Notice that he says "usually". Just because there is no winging doesn't necessarily mean there is a dislocation (this from a hopeful parent!!).

I wonder if there are any other movements associated with the serratus anterior that may be dysfunctional? Or for that matter, if there are any other muscles that are affected that I am not aware of.

FYI--Here is an interesting site about anatomy. No gory pictures just drawings. Good information about the muscles, bones and nerves of the body. The link below is for the shoulder, but using the index you can find anything in the body.
http://www.bartleby.com/107/83.html

Thanks again,

Clint

I'm confused on the mod quad part. I understand how the mod quad may unmask and not cause the dislocation. But does it happen during the surgery? And if so, is the surgeon aware of it?

Tina

I still don't get it..too techinal for me... plus what I am really intrested in is long term... is winging bad long term? If so how can we fix it that?
Thanks for helping! I appericate it!
Kristie

I will ask him your questions...
-francine

The dislocation is unmasked later during recovery, as the child recovers new
functions he/she did not previously have. Also, the effects of nerve injury
on the shoulder joint are progressive so that early quad surgery may actually
prevent dislocations. There is no indication during surgery whether the child
will go on to develop problems at the shoulder, but many times the internal
rotation posture prior to any surgery alerts the surgeon that the dislocation
already exists.

Long term, winging does not seem to inhibit movement greatly but does pose a
cosmetic concern. Taping and other maneuvers are probably helpful to some
extent but I would not say it was crucial to completely reverse winging.

R.Nath

Well isn't winging intersting? Ashley wings in both shoulders, does any of your children do this? When she is bearing weight both her shoulders stick way out...lokks painful too!

Lenni

I hate to be a bother but what about pain... does a winged scapula cause pain? Especially long term? Like Lenni mentioned it sure does look like it would. I once saw a photo of an adult with a major winged scapula and got a sore back just from looking at it.
Thanks again,
Kristie

double winging here too--even before the BPI started winging. Also, does it not inhibit ROM? It sure looks like it does.

Guess what -- I did not know I had scapular winging until I was about twenty and saw a photo of myself on the beach... I did not ever think much about it after that either... It was never a big deal in my mind... it that helps any... of course I am only talking about the way it looked...

When I saw the photo I told my Mom and she said " thats why I called you my angel with the broken wing" and that was that... never even mentioned it again... I guess she made me feel it was no big deal... and so it was no big deal... Wonder what she really thought about it...
Kath