Humans talk with the larynx, or voice box. This small but versatile apparatus is at the back of the throat, at the very top of the air passage called the trachea. It is both formed by, and is supported by, the cartilage rings of the upper airway. Inside it are the two vocal cords, which are the topmost parts of the vocal folds.
The folds are formed by thin bands of smooth muscle on opposite sides of the airway, covered by mucous membrane. They extend from the front to the back of the larynx, where they are attached to the arytenoid cartilages, which appear as a pair of bumps in its posterior wall.
Their contraction is controlled by a pair of nerves called the recurrent laryngeal nerves. They are spaced most widely during inhalation, but approach each other during voice production, and during swallowing. They appear as glistening white cord-like structures, arranged in a V. The opening to the airway below is through the vocal cords.
Voice and how it is formed
The human voice is created when the air in the lungs is pushed out between the contracting vocal cords. This contraction is modulated by the nerve signals, and opens the vocal cords to varying extents. The air pushing out between the cords produces vibrations of the cords, resulting in the production of sound.
The quality, pitch and resonance of the sound are adjusted by the movement of the cartilages, which tighten or relax the cords, changing their spacing and thickness. They vibrate between being open and closed when they are in use for talking.
The vocal cords also represent the opening to the trachea, and are therefore protected from the inadvertent entry of food or other foreign particles by the epiglottis. This is a flap of cartilage which bends over to close the opening every time the tongue moves back to enable swallowing.
Most vocal cord diseases manifest themselves first by hoarseness. Inflammation of the vocal cords is called laryngitis, and may be acute or chronic.
Vocal cord injury occurs in many ways, such as talking for too long, singing too high, clearing the throat too often, yelling or smoking. These lead to overstrain of the larynx, which causes overgrowth of tissue on the vocal cords. The result is a vocal cord nodule, polyp or ulcerated area, manifesting as the hoarseness of chronic laryngitis.
Other causes of vocal cord malfunction include acute laryngitis due to infections which cause swelling of the cords, exposure to airborne chemical pollutants, reflux esophagitis, nerve injuries, which may be traumatic or may follow some types of throat or neck surgery, viral papillomas, or tumorous growths.
Thus inflammation of the vocal cords occurs in acute or chronic laryngitis. Cancers of the vocal cords are either squamous cell or verrucous carcinomas, and are almost always associated with smoking.
Symptoms of vocal cord dysfunction include:
- Loss of vocal range
- Raw feeling at the back of the throat
- Always having to clear the throat
- Breathing difficulties – mostly in nerve injury which leaves the cords closely apposed.
Diagnosis and treatment
Diagnosis of vocal cord disease is based on the symptoms followed by an examination of the voice, and direct inspection of the cords, using a laryngoscope. Other diagnostic techniques include X-rays of the neck, and biopsy of any growth.
Conditions affecting the vocal cords can often be treated, especially if they are caught early. Treatment depends on the specific cause, and may include rest by not speaking for a couple of weeks, steam inhalation, antibiotics for infections, and surgery when required, as for nodules or polyps, or for tumors of the larynx.
Taking care of your vocal cords
Just like any other organ, the vocal cords need to be treated well if they are to last a lifetime. A few simple ways to care for them include:
- Protection against overuse, especially if your profession depends on the use of your voice, as in the case of singers, teachers, salespeople or health professionals.
- Drinking plenty of water.
- Using a humidifier to prevent the vocal cords from drying out.
- Avoiding medications which cause throat dryness.
- Avoiding smoking, alcohol, caffeine, spicy food.
- Treating gastroesophageal reflux.
- Adequate exercise and rest.
- Voice training to use the voice properly.