scalene hypertrophy

Scalene Hypertrophy

I recently evaluated yet another Major League baseball player with the “yips,” or what I like to call thoracic outlet syndrome.  I really don’t believe in the yips at all and feel that thoracic outlet syndrome is almost always to blame.  Telling a professional athlete it’s all in their head or some mysterious mechanical flaw is just insulting.

One of the major reasons that thoracic outlet syndrome occurs in baseball pitchers is from hypertrophy of the scalene muscles (and sternocleidomastoid).  Throwing a baseball causes many adaptations to the body, including this increase in scalene size.

Here is a video of the athlete inhaling with his head turned to each side.  Notice the significantly larger scalene and sternocleidomastoid on his right side.


scalene hypertrophy

I wish I had a magic trick to help in this situation.  I will perform manual therapy on the scalene muscles, surround musculature, 1st rib, and thoracic cage, however, it’s hard to combat the hypertrophy associated with throwing.

Understanding what to look for is the first step, though.  Scalene hypertrophy is a subtle finding to detect on examination.



14 replies
  1. Kairee Tekra
    Kairee Tekra says:

    EMG tests don’t seem to be all that accurate especially if it’s something that’s so subtle. How does one know for sure that they have it?

  2. Tom Ellis
    Tom Ellis says:

    Hi Mike, do you have any idea whether these cases are permanent hypertrophy or temporary swelling or inflamation which will diminish with time?

  3. Adam Trainor
    Adam Trainor says:

    Wow. Geez, maybe throw with the opposite hand in the off-season? I think Vincent Brunelle DC had the best suggestion yet. I am going to assume that these players typically do not spend much time with the lacrosse ball. Kelly Starrett demos a mobility technique for getting that first rib down. He lays supine, with a dowel pressed one end into a wall, and the other into the space where the top of the first rib is. There a tennis ball over the body end of the dowel to distribute the pressure a little. Then it’s time to push that rib down as much as you can take it. Ouch.

  4. Vincent Brunelle DC
    Vincent Brunelle DC says:

    Mike, how often do you find antagonistic muscle lagging? Could you lessen the impact of the scalene hypertrophy with 1st rib work, breathing corrections and some work on the levator scap.? is it possible to lessen the hypertrophy by correcting the structural load on the c spine? What is the typical radiographic presentation of the athlete?

  5. mikereinold
    mikereinold says:

    @2strongthumbs:disqus , sorry, are you asking what are the “yips?” @disqus_pKAwjhYZ7m:disqus said it well, the yips in baseball is when a player can’t throw strikes. If you have subtle issues with neurological and vascular function in your arm it is really hard to detect subtle differences in arm position etc. I’m saying I don’t think a professional MLB pitcher can go from that elite of a level to all of a sudden not being able to throwing strikes.

  6. Elsa
    Elsa says:

    In baseball, YIPS carries superstition. It’s made out to be mental. Mike’s saying TOS is a huge player in the manifestation of YIPS.

  7. 2strongthumbs
    2strongthumbs says:

    What are you trying to say in the first paragraph? Yips = TOS; don’t believe in Yips, TOS is to blame…. Huh? YIPS?

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