Vocal cords

The vocal cords are two folds of skin (membranes) stretched across the larynx which open and close, depending upon air pressure. These flat, white triangular bands of tissue are attached to the rear of the throat by fibres of cartilage. The outer edges of the vocal cords are connected to several areas of the larynx whilst the inner sections or the ‘hole’ are left free.

Above these lie the ‘false vocal folds’or ‘vestibular folds’: these are thick folds of skin which sit above the real or ‘true’vocal cords. The false vocal folds help to protect the true vocal cords and enable the person to produce deep vocal tones when singing or chanting.

The true vocal cords sit above the trachea and just below the epiglottis.

What is the difference between male and female vocal cords?

The main difference is that male vocal cords tend to be larger which affects the pitch of their voice. Men have deeper voices than women which is due to this plus genetics and hormonal influences. For example: male vocal cords are around 17 to 25mm in length: whereas female vocal cords are around 12 to 17mm in length.

How do the vocal cords work?

They open when we inhale and close when we hold our breath. They also vibrate or oscillate during speech or singing. As someone inhales the vocal cords close to enable air to reach the lungs. As that person goes to speak, their diaphragm lifts up which then expels air through the vocal cords. This causes these cords to vibrate and generate sound.

The types of sound depend upon the degree of vibration. This vibration is determined by the extent to which the vocal cords open: in other words, how wide they open which will affect how much they vibrate. This vibration along with the size of the vocal cords plus movement from the tongue and/or mouth will result in different types of sounds.

The size of your larynx plus the size and depth of your vocal cords will determine the tone and pitch (frequency) of your voice. This differs from one person to another which is why we all have individual voices. One of the major contributors of these sounds is the larynx. This causes a build up of air when the vocal cords are closed which are then forced apart by this pressure. This air is separated into sound waves which are controlled by the extent to which the vocal cords open and stretch.

Basically, the vocal cords move apart when you breathe in (inhale) and come together when you breathe out (exhalation). This affects the amount of air which passes through.

The vibration of the vocal cords is what enables us to talk and communicate with others. Speech is discussed in more detail in our how the throat works section.

The vocal cords are robust but like any part of the body they can become damaged through overuse, strain, illness and infection.

What health problems affect the vocal cords?

The most common problems include vocal polyps, sores, nodules and strain. Other conditions include Reinke’s oedema, vocal cord paralysis and laryngitis.

Several of these are discussed in greater detail in our throat related problems and throat infections sections.

Vocal polyps, sores, nodules and strain are usually caused by overusing the voice, for example, shouting, coughing and talking. Many singers find that they develop a nodule or polyp on their vocal cords which is often a result of excessive use of their voice. Singing or talking in a smoky environment is another factor. Cigarette smoke irritates the delicate tissues of the throat which causes it to become dry, swollen and inflamed. If you use your voice in a professional capacity then find out more in our looking after your throat section.

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