Mike wrote:
<< your responses have been very helpful and very clear. i would like to
ask you how the contraction of the thyroarytenoids contribute to adduction,
if you don't mind. what i'm ultimately after is knowing whether adduction
(for singing) is simply aligning the folds together or, is it squeezing them
together (far more likely but, i'm trying to assume nothing) and how much
more do they squeeze together as pitch is increased?>>
David responds:
Thank you! According to Miller, the thyroarytenoids pull the vocal
processes downward and inward, which approximates the vocal folds. They
also can shorten the vocal folds, which helps in singing low notes. As I
understand it, the approximation of the vocal folds is only part of the
solution toward complete (and free) adduction of the folds. Somewhere along
the line, Bernoulli's effect comes into play, once the glottis has been
sufficiently narrowed. It (the balance of muscles used) can vary according
to whether you are singing full chest, or head voice, or something inbetween
as well, because as the cricothyroid tilts the thyroid (or the
cricoid--depends on who you read), the cricoarytenoid helps to close the gap
that naturally occurs through the action of the CT. So, as pitch is
increased there is action from the cricothyroid (to strecth the cords) and
more action from the crocarytenoid (to offset the gap created by the CT's
action). This increases medial compression of the cords.
Mike also wrote:
<< as i write the above question, it occurs to me that, in order to
reduce
the use of 'chest voice' as one increases pitch, the role of the vocalis
muscle in adduction has to lessen. so, if the squeezing of adduction were
to increase as pitch increases, that increase in squeezing would have to be
taken by one of the other muscles we've discussed.>>
David responds:
Right...see above. Thanks for the discussion.
David Grogan
ETBU Music
Marshall, Texas
dgrogan@e...
dgrogan@e...
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