Your Vocal Cords (technically Vocal Folds)

Your Vocal Cords (technically Vocal Folds)

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Last updated on April 14th, 2024 at 02:04 pm

Last Updated on April 14, 2024 by Karmyn

It’s hard to quantify singing when you can’t look down into your throat and see what happens when you make a certain sound. So, through the years, great teachers have used words to communicate how to make an optimal sound.

Today, with the help of science, we can see and make better sense of those words.

Watch this video by Dr. James Thomas:

In the video, you learned that the larynx is a rather miraculous valve. It has 3 functions:

1. to regulate breathing,
2. create sound,

3. and keep food and liquids out of the lungs.

As singers, we are obviously focused on the creating sound part. So, let’s talk about the vocal muscles first….before breathing and before alignment. 

The vocal cords, or technically the vocal folds, are housed in the larynx (commonly called the voice box). Let’s look at the Intrinsic Muscles with more from Dr. James Thomas in his book Why is there a frog in my throat? A Guide to Hoarseness.

The intrinsic muscles of the larynx are composed of 10 muscles. These muscles change the position, length, and tension of the vocal folds.

There are 5 paired muscles on each side of the larynx. 

Muscles of the Voice

TA – ThyroArytenoid

LCA – Lateral CricoArytenoid 

PCA – Posterior CricoArytenoid 

CT – CricoThyroid 

IA – InterArytenoid 

The TA – ThyroArytenoid muscle lies within and run the entire length of the vocal cord. It tightens to increase pitch mostly by isometrically tensioning the vocal cord. For singers when they are not engaging the CT muscles, the TA muscle essentially is used to change pitch throughout their lower or chest register.

Cricothyroid Joint

The CT – CricoThyroid muscle is located on the exterior of the larynx, just under the skin. The thyroid cartilage pivots or rocks forward on top of the cricoid cartilage when the CT muscle contracts. We call this the cricoid tilt.

            The effect of this rocking is to stretch the vocal cords. For the singer, the additional tension provided by stretching the vocal cords provides the falsetto (upper or head) register. The tension of the CT also allows us to yell with less effort.

NOTE: We basically have 2 muscles that execute pitch. The primary low range uses the TA and the primarily high range uses the CT. That said, there is a tensioning where the two muscles blend together. For the singer, this is called the vocal “break.” Most singers spend the bulk of their training learning to have a smooth transition between the use of these two muscles.

Here are the other muscles:

The LCA (Lateral CricoArytenoid muscle) brings the vocal cords from an open breathing position together to a closed position in preparation for making sound. The LCA is attached to the outer end of the arytenoid cartilage which acts as a lever.

The IA (InterArytenoid muscle) holds the vocal cords in a closed position after they have been brought together by the LCA muscles for phonation. The IA muscle from one side attaches with the IA muscle from the other side.

Try this:
Take a breath and get ready to phonate the vowel AA as in the word “apple.” (LCA) Now right before you phonate, hold that position. (IA) 
The PCA (Posterior CricoArytenoid muscle) is located on the back of the larynx, behind and lateral to the arytenoid cartilage. It pulls on the arytenoid cartilage to open the vocal cords for breathing. The effect of contraction of this muscle can be visualized as the exact opposite effect of the contraction of the LCA muscle.

The PCA muscle is strongly activated by sniffing. During a brisk sniff through the nose, the PCA muscles contract, and each vocal process moves laterally, increasing the size of the glottis.

The PCA should not be felt while you are phonating since you are pulling the glottis (opening) apart and you want to do the opposite to make a sound.

Your, hyoid bone, Thyroid cartilage (vocal box), and cricoid cartilage are suspended by muscles. The hyoid bone is connected to the tongue and jaw muscles above and the thyroid cartilage below. It is then connected by the cricoid muscles to the cricoid cartilage making the bottom of the larynx. 

Now that you have a basic understanding of the muscles that work to produce sound, see if you can imagine all of these movements happening smoothly as you used your voice.

Bonus:

TA – ThyroArytenoid (lateral Thyroarytenoid is a Relaxer)

LCA – Lateral CricoArytenoid (Adductor – close the vocal folds) 

PCA – Posterior CricoArytenoid (Abductor – open the vocal folds)
Side note – The PCA is the only abductor because it takes less effort to keep the vocal folds open than bring them together. For example, when you breathe, your vocal folds remain open.

CT – CricoThyroid (along with the vocalis muscle is a Tensor)

IA – InterArytenoid (the transverse arytenoids and oblique arytenoids – Adductors)

2 Responses

  1. Nicolette Ribeiro
    | Reply

    hello I was interested in the first image you have at the top of the article, could you let me know if there are any copyright laws surrounding its use, I am a research assistant for Nova Southeastern University and was interested in using it in an academic presentation.

    • Karmyn
      | Reply

      Hello! Yes, It came from The Anatomical Chart Series Classic Library Edition, Copyright 1993, Anatomical Chart Co., Skokie,Illinois, Library of Congress number 86-071078 and ISBN 0-9603730-3-9 page 22
      Hope that helps!

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