Elizabeth Tait OB Ch. 16 Summary

Summary: "The more you understand the anatomy and physiology of voice production, the better equipped you will be to sing or to teach singing."  There are nine functions of the vocal folds, only one being voluntary phonation for communication.  The reflexive functions of the vocal mechanism is one indicator that explains why it "has been described as the most complex and versatile mechanical device in the body."  The principle framework of the larynx is comprised of the cricoid, arytenoid, and thyroid cartilages.  These three pieces are suspended from the hyoid bone, which creates the top barrier of the larynx.  There are a lot of freaking muscles in there that do a lot of things, some which I will attempt to successfully explain now:
Thyroarytenoid muscle: They are the two vocal folds, and they can both contract (which shorten and thickens the folds), and relax (which stretches the folds.)
Posterior Cricoarytenoid muscles: Connecting the posterior surface of the cricoid and the posterior arytenoids, these muscles abduct the vocal folds
Lateral Cricoarytenoid muscles: Connecting the upper cricoid and the anterior arytenoids, these muscles adduct the vocal folds.
Interarytenoids: Connecting the two arytenoids both transversely and obliquely, these muscles close the posterior portion of the vocal folds ("chink").
Cricothyroid muscle: Connecting the cricoid and thryroid, these muscles have two parts, the pars recta and pars obliqua.  The pars recta approximates anterior thyroid and cricoid, which elongates and tenses the vocal folds.  The pars obliqua pulls the thyroid anteriorally, which further stretches the folds.
There are a great number of extrinsic muscles that connect the shoulders, tongue, jaw, and other stuff to the hyoid bone.  I won't go into detail about them all, but the principle is that freedom of extrinsic muscles allows for freer phonation in the larynx. 
Key Terms (there are many)
9 functions of vocal folds:
respiratory
valvular
fixative
protective
deglutitory
tussive
expectorative
emotional
phonatory
Framework of Larynx is already listed above, along with intrinsic muscles...
Extrinsic muscles:
sternohyoid, sternothyroid, omohyoid, thyrohyoid, digastric, stylohyoid, geniohyoid, genioglossus, hyoglossus, mylohyoid.
Key Concepts: There is a freaking large quantity of muscles associate with phonation.  Don't be so prideful as to think you can control them all!  Just get out of the way. 
Making Connections: It especially interested me that there are more muscles that naturally raise the larynx than those that lower the larynx.  So lowering the larynx is more something we don't do rather than do.  That is especially interesting in light of my research project for Dr. Scheer's class, which seems to be revealing that low larynx was not a principle of singing until the 19th century.