Vocal cords, more accurately called vocal folds, are two small bands of muscle and tissue stretched across your larynx (voice box) that produce sound when air from your lungs passes between them. In adults, they’re surprisingly tiny: roughly 15 mm long in men and 11 to 13 mm in women, or about the size of a dime. Despite their small size, these structures are responsible for every sound you speak, sing, whisper, or shout, and they also play a critical role in protecting your airway when you swallow.
Where Vocal Cords Sit in Your Throat
Your vocal cords live inside the larynx, a small cartilage structure in the front of your neck (the bump you can feel is part of it). They’re positioned horizontally, attached at the front to the inside of the thyroid cartilage and at the back to two small, movable pieces of cartilage called the arytenoids. The gap between the two vocal folds is called the glottis.
The folds themselves aren’t simple flaps. They have a layered structure: a muscle body on the inside, a gel-like middle layer, and a thin, flexible outer covering of mucous membrane. This layered design is what allows them to vibrate in complex wave-like patterns rather than just snapping open and shut.
How They Produce Sound
Voice production starts with your lungs pushing air upward. When you decide to speak, muscles in your larynx pull the vocal folds together, closing the glottis. Air pressure builds beneath the closed folds until it’s strong enough to push them apart. Once the air rushes through, a combination of the tissue’s own elasticity and a drop in air pressure (the same principle that lifts an airplane wing) snaps the folds back together. This cycle repeats rapidly, chopping the airstream into tiny pulses that your ears perceive as sound.
The speed of this open-close cycle determines pitch. Men’s vocal folds vibrate between about 90 and 500 times per second, averaging around 115 Hz in normal conversation. Women’s folds vibrate between 150 and 1,000 times per second, averaging about 200 Hz. That means during a casual conversation, a woman’s vocal folds are opening and closing roughly 200 times every second.
Pitch control is largely muscular. Your laryngeal muscles can stretch and thin the vocal folds to raise pitch (similar to tightening a guitar string) or relax and thicken them to lower it. Volume, on the other hand, comes from pushing more air pressure through the folds, which causes them to stay closed longer during each cycle and release bigger bursts of air.
Opening, Closing, and the Nerves in Charge
Your vocal folds do more than make sound. They open wide when you breathe, close firmly when you swallow (to keep food out of your lungs), and come together with precise tension when you speak. Two sets of muscles handle this. One pair pulls the folds apart for breathing. A separate pair draws them together for speaking and swallowing. These are the only muscles in your body dedicated solely to opening the airway, which is why damage to them can be serious.
Two branches of a nerve called the vagus nerve control nearly all of this movement. The recurrent laryngeal nerve handles most of the intrinsic muscles, while the superior laryngeal nerve controls one muscle involved in pitch adjustment and provides sensation to the tissue above the folds. If the recurrent laryngeal nerve is injured, whether from surgery, a tumor, or trauma, the vocal fold on that side can become paralyzed. This causes a breathy, weak voice and, more importantly, increases the risk of food or liquid slipping into the airway during swallowing.
Why Hydration Matters for Your Voice
The vocal folds need to be well-lubricated to vibrate efficiently. A thin layer of mucus coats their surface, and the tissue itself contains water that keeps it pliable. Research on excised vocal folds has shown that dehydration increases the tissue’s stiffness, making it harder for the folds to vibrate. This means your body has to generate more air pressure just to start producing sound, which creates a strained, effortful feeling when you talk.
Rehydrating the tissue reverses this effect, restoring the folds’ flexibility and lowering the air pressure needed to speak. This is why singers and professional voice users are often advised to drink plenty of water. It’s not that the water you swallow touches your vocal folds directly (it doesn’t, or you’d choke). Instead, systemic hydration, the water circulating through your body, keeps the vocal fold tissue supple from the inside out. Caffeinated drinks and dry environments work against this by pulling moisture from your tissues.
Common Vocal Cord Problems
Because the vocal folds collide with each other hundreds of times per second during speech, they’re vulnerable to wear-and-tear injuries, especially with heavy or forceful voice use.
Nodules
Vocal cord nodules are callous-like growths that develop at the midpoint of the folds, where impact force is greatest. Sometimes called singer’s nodes or screamer’s nodes, they form from repeated overuse or misuse of the voice over time. They typically respond well to voice therapy with a speech-language pathologist, which focuses on changing the vocal habits that caused the problem. Surgery is reserved for cases that don’t improve with therapy.
Polyps
Polyps can also result from chronic overuse, but unlike nodules, they can form after a single episode of vocal abuse, like screaming at a concert or sporting event. They tend to be softer and more blister-like than nodules and usually require surgical removal because they don’t respond well to voice therapy alone.
Cysts
Vocal cord cysts are fluid-filled or semi-solid growths surrounded by a sac. They form when a gland in the vocal fold gets blocked or when cell debris becomes trapped in the tissue. Unlike nodules and polyps, cysts aren’t necessarily linked to voice overuse, so they can develop even in people who don’t strain their voices. Like polyps, they generally require surgery.
How Vocal Cords Change Over a Lifetime
Children’s vocal folds are shorter and thinner than adults’, which is why their voices are higher-pitched. During puberty, a surge of hormones (particularly testosterone) causes the larynx to grow and the vocal folds to lengthen and thicken. This is more dramatic in boys, whose folds roughly double in length, producing the characteristic voice “break” and eventual deepening. Girls experience a subtler change.
In older adults, the vocal folds gradually lose muscle mass and the layered tissue becomes thinner and stiffer. The result is often a thinner, breathier, or shakier voice. Some of this is a normal part of aging, though staying vocally active and well-hydrated can slow the process. Hormonal changes after menopause can also lower women’s voices slightly as the tissue composition shifts.