Anatomy and Physiology series: Muscles of the soft palate

Now, we're getting into the articulatory system...which also doubles as the chewing/swallowing mechanism.  We're gonna start with the soft palate, or velum.  The nice thing about talking about the articulatory system is that you can see most of it in action with your own open mouth and a mirror, but I'll put up a couple of pictures to help out anyway.

Front view of the velum from an opened mouth.  It ends at the uvula.

Side view of the velum.  Allows you to get an idea of how it opens and closes the nasal port.

The velum opens the nasal port when it's elevated, and closes the nasal port when it's depressed.  As such, there are velar openers and velar depressors.  There is also one curious little muscle that used to be thought of as an elevator, but we now know that it is not.  I'll also go over that one too.  So on to the elevators:

The levator veli palatini is the primary elevator of the velum.   It originates from the petrous portion of the temporal bone, and inserts into the palatal aponeurosis.  (I know that contains a fair number of heavy anatomical terms.  Seriously, the first time I heard the term "aponeurosis" my brain just went, "huh?".  If you've never heard of them before, just click the links to get a quick definition at the top of each page.)  This muscle elevates and pulls back, or retracts, the back of the soft palate when contracted.  

Another elevator is the musculus uvulae.  If you look at the first picture I posted, this is the muscle embodied within the uvula there.  Contraction of this muscle shortens the soft palate, basically bunching it up towards the back.  

The two depressors are the palatoglossus muscle and the palatopharyngeus muscle.  The palatoglossus originates from the palatal aponeurosis and inserts into the sides of the back of the tongue.  So, really, this is both a palatal and a tongue muscle.  Contraction both elevates the tongue and depresses the velum...but don't over think that as a singer, cause this coordination is all under the nervous system's control (so if it's functioning well for you, over-thinking it could muck up what's already working well.)  This is why I am going to culminate this whole A&P series with a introduction into the nervous system, so stay tuned for that!

The palatopharyngeus muscle is another duel-duty muscle, being both a palatal and pharyngeal muscle.  This guy originates from the hard palate and inserts into the back of the thyroid cartilage, so it's pretty long in comparison to others.  Contraction of this muscle both constricts the pharynx and lowers the soft palate.

*So here's a little physiology note:  When at rest, the velum is depressed, allowing us to breath through our nose comfortably.  So why do we need velar depressors?  Well, the velum is elevated most of the time during speech (or singing), but when we want to make nasal sounds, like /m/ /n/ or nasal vowels, we've got to depress it very quickly.  This is where the depressors come in, especially the palatoglossus.  Allowing the elevators to simply relax would be too slow for comprehensible, flowing speech.  

And the last muscle is the tensor veli palatini.  Did you go to the link and read about it?  Cause if you did, forget what you just read.  This is an instance where wikipedia is out of date and inaccurate.  For a long time, we thought this muscle tensed the velum thereby assisting the levator veli palatini in elevating the larynx, but we now know that this muscle doesn't elevate the velum at all.  It's sole function is to open the Eustachian tube to allow the air pressure in the middle ear to equalize.  This is the muscle at work when you either yawn or chew gum on a plane to get  your ears to "pop."  (This is also why babies always cry after take-off, cause they don't know to "pop" their ears, and this muscle doesn't work as well for them.  They're just uncomfortable when the pressure changes, and an uncomfortable baby is a crying baby.)

Up next is tongue musculature, which is gonna be a long post 'cause there's a lot of them!

*Seikel, J. A., King, D. W., & Drumright, D. G. (2010). Anatomy and physiology for speech, language, and hearing. Clifton Park, NY: Delmar.