United Brachial Plexus Network, Inc.

Can anyone describe this to me? I've seen it used on here several times and don't know what it means. Thanks!

It's actually SUBLUXATION..

http://www.caringmedical.com/conditions ... ility).htm
"A shoulder subluxation or instability involves a temporary, partial dislocation of the shoulder joint. The shoulder is made up of a ball-and-socket joint in which the ball of the upper arm bone is normally held in the socket of the shoulder blade by a group of ligaments that connect to the bones. In a shoulder subluxation, the ball of the upper arm bone slips partially out of the shoulder socket."

Now in BPI kids, it's also from the malformation of the joint and the weak muscles/muscle imbalance that cannot hold the joint in place. It also is not temporary, but more likely to be permanent in BPIs.

Katep explains this well... hopefully she'll see this and can help
Marieke (31, LOBPI)

Well, here is something I wrote up for another group but it really needs the pictures (MRI scans of shoulders showing progressive malformation of the shoulder) that go along with it. If someone has a place I can put it along with the pictures I'd be happy to put the whole thing there.

~~~~~

I want to comment on the descriptions of subluxed and dislocated for the shoulder that one can find in textbooks or on the internet. Please keep in mind these apply to a "normal" shoulder; as we know, BPI is much different and this is one area where BPI is *very* different.

Normal shoulders simply do not sublux or dislocate without some sort of associated trauma. In addition, when you hear or read about shoulder dislocation in "normal" shoulders, it almost always refers to anterior dislocation. That is because, in normally developed shoulder joints, there are very strong structures - ligaments, cartilage and boney orientation - which prevent posterior dislocation. Posterior dislocation only occurs under severe force in "normal" shoulders, usually also causing bone damage or fracture. Major athletes, like pitchers, sometimes develop enough repeated small injuries that eventually add up to reduced shoulder stability. Rarely, mentally ill patients develop a habit of purposefully subluxing their shoulders posteriorily, which over time can also result in posterior instability. Those are basically the two ways a posterior dislocation can "happen" without BPI - significant trauma (either major impact or injuries over a long, long period of time) or mental illness!

BPI shoulders, on the other hand, often just grow wrong from the start due to the muscle imbalances, which also results in posterior instability, subluxation and sometimes dislocation. Docs usually use the term "subluxed" when referring to BPI shoulders, because it is really one big continuum. Basically, here is the progression

1) Early muscle imbalances cause the glenoid to start to malform, growing more on the anterior (front) aspect and less on the posterior (back) part. This can happen within the first few months of life.

2) The glenoid and humeral ball continue to grow "together" but in a progressively deformed way. The glenoid becomes progressively "retroverted" (facing backwards) and the humeral ball develops flat places and non-round areas. The humeral ball remains centered on the malformed glenoid, but the entire glenohumeral joint is out of alignment with the rest of the scapula.

3) If left unchecked, the humeral ball and the glenoid will continue to try to mutually accomodate each other, with the humeral ball getting further and further displaced rearwards with the glenoid trying to accomodate. Sometimes the glenoid will develop a new surface ("pseudoglenoid") which will continue to partially articulate with the severely subluxed shoulder.

4) Eventually, if muscular imbalance continues and as the child grows, the ball can shift so far back in the socket that the shoulder becomes completely unstable. This explains why the real major problems due to muscular imbalances and glenohumeral joint malformation often are not revealed until the child is older.

During early childhood the body is growing fast, and glenoid and humerus are constantly growing and accomodating each other to maintain equilibrium in the joint. When musclular imbalances continue (or grow worse, as occurs in adolescence) at the same time the shoulder joint growth slows, the glenoid may no longer be able to accomdate the shifted shoulder joint, and true dislocation due to instability occurs. This instability is exacerbated by increased weight of the arm as the child gets older.

So whereas in a normal shoulder, ligaments, the cartilage "rim" of the glenoid or even the glenoid itself would need to be torn or fractured to allow a posterior dislocation, in BPI kids with severely malformed shoulder joints the humeral ball will often be able to slip in and out of full dislocation easily. Frank shoulder dislocations - where no part of the joint is in contact with the humeral ball and the ball needs to be surgically or forceably reduced - is rare in BPI. It is more a form of structural instability - in a shoulder severely malformed due to BPI, the structure is just not there to provide for a stable joint.

Thus, when you hear of BPI kids whose shoulder joints "dislocated" from something that sounds benign, it is almost certainly because the child had an unstable shoulder joint to start with.

Kate

My son Dylan had one about 8 months ago. I don't know if its the same for everyone but I know that with dylan because of the lack of movement in his arm, it was weighing his arm down and basically his shoulder started to droop. Which created a small hole between I think his tendons and his bone. Its something you can actually feel. In his case. I felt a lot. But his therapist would tape his shoulder with kiniseo tape. And this has helped him greatly. It's almost completely gone. Also It's kind of preventable. It would be a hassle. But just try not to let your child's arm hang all of the time. And you could prevent a severe case of it.
Jessica

It's so hard to visualize. I think I'll ask our OT about it on wed when we go. Thanks you guys!