Coup de glotte: Membraneous and Cartilaginous Adduction

I read a great science paper yesterday, that was published in the Journal of the Acoustical Society of America in 2011. 

Authored by Christian T. Herbst, Qingjun Qiu, Harm K. Shutte, and Jan Svec, the paper, “Membraneous and cartilaginous vocal fold adduction in singing,” covers several maneuvers of glottal closure in the singing act.

To give the reader a quick overview of physiology, the vocal folds can be divided along their length into a membraneous portion and a cartilaginous portion. The membraneous portion is between the anterior (in front) commissure and the vocal processes of the arytenoid cartilages. The cartilaginous portion is the segment between the arytenoid cartilages and the posterior (in back) commissure of the vocal folds.

Here is a graphic showing these portions of the glottis:

glottis_anatomy1352409946740

The cartilaginous portion of the glottis is brought together (or adducted) by two main muscles, the lateral cricoarytenoid (LCA) and the interarytenoid (IA) muscles. The LCA brings together the vocal processes (i.e., the anterior prominences of the arytenoid cartilages), and the IA brings the posterior parts of the arytenoid cartilages together.

The muscles that OPEN the glottis are the posterior cricoarytenoid muscles. These are the only muscles that move the vocal processes apart, and because of this action are vital to the act of inhalation. If these muscles were not active, we would suffocate. These opener-muscles are also highly active and engaged in a pure falsetto tone, but I digress…

The adductory position of the cartilaginous portion of the glottis in phonation is very important, because the positioning of the vocal processes determines the position of the membraneous portion of the vocal folds. In a breathy voice, the adduction of the cartilaginous portion is rather weak, or hypofunctional. In a pressed or squeezed voice, they are too active, or hyperfunctional.

Why does this matter for bel canto, or for singing at all?

Two reasons: 1) It verifies Garcia’s ideas of glottal closure via the coup de glotte, and 2) would physiologically demonstrate a bifurcated muscular system which would provide mechanics for a two-register view (chest/falsetto) of the voice. This also supports Garcia’s assertion of vocal registers as a ‘mechanism.’

I first learned about this membraneous versus cartilaginous adduction in James Stark’s excellent and highly recommended book Bel Canto: A History of Vocal Pedagogy. Stark argues that Garcia’s coup de glotte was a form of cartilaginous adduction in which the the glottis was drawn together milliseconds prior to phonation (Garcia also used the term ‘pinch of the glottis’). This ‘shortened glottis’ (only the membraneous portion was being activated following cartilaginous adduction), gives the singer a bright, ringing tone. This lends credibility to Garcia’s description of resultant ‘ring and roundness’.

Modern ideas of onset, through influential authors such as Richard Miller, favor a ‘simultaneous’ or ‘balanced’ attack/onset. This onset is an adductory behavior wherein the entire length of the fold is drawn into vibration simultaneously. This modern onset is not the same mechanically as Garcia’s coup de glotte, or ‘shortened glottis.’

Daniela Bloem-Hubatka explores the importance of this cartilaginous adduction in her book The Old Italian School of Singing:

In the singing after the Old Method there is no pressure on the vocal cords themselves because the preparation for the emission of voice so perfectly executed by the situation around them, the false cords and the arytenoid cartilages, that the vocal cords can do their work of vibration easily. The vocal longevity, elasticity, youth and freshness of the historical singers thus becomes understandable. To enable the vocal cords to vibrate freely, it is necessary to keep them in close approximation by means other than the vocal cords themselves. They can stand quite a bit of pressure but this will diminish their ability to vibrate considerably. There is a mechanism that acts on the vocal folds in the form of a pair of cartilages similar to a pair of lever-quadrants fastened to the posterior ends of the vocal cords. This mechanism consists of the arytenoid cartilages that open the glottal lips for breathing silently and close them for vocal sound production.

[…]

Kelsey compares the pressure point of the arytenoid cartilages to the pressure point that we obtain by pressing our first finger and thumb together. We feel the sensation at the point of contact of the fingers but not the action of the muscles that set the finger points in motion.

“Just as the pressing together of thumb and finger, however lightly, is always felt as positive act of pressure, so in the case of the arytenoids, their mutual adherence is always felt as a point of pressure somewhere in the back of the larynx. Thus the singer makes his ‘lip’ by means of a continuous act of pressure at the posterior end of the glottal lips.” (Kelsey, Foundations of Singing)

The coup de glotte and registration of the voice is becoming the cornerstone of my work with students in the studio. Utilizing these ideas in praxis is exciting because the freedom they allow a singer gives them an opportunity for greater expression and musical creativity and sensitivity. As isn’t that really the goal of any technique of singing?

Play with coup de glotte for a week. I can guarantee it will teach you something.

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