Anatomy: Vocal Fold Vibration

1 Column of air pressure moves upward towards vocal folds in "closed" position	(click for larger image)	6–10 The low pressure created behind the fast-moving air column produces a Bernoulli effect which causes the bottom to close, followed by the top
2, 3 Column of air pressure opens bottom of vibrating layers of vocal folds; body of vocal folds stays in place		10 Closure of the vocal folds cuts off the air column and releases a pulse of air
4, 5 Column of air pressure continues to move upward, now towards the top of vocal folds, and opens the top		New vibratory cycle – repeat 1-10

In the closed position (---) maintained by muscle (), the key vibrating layer of the vocal fold () opens and closes in a cyclical, ordered and even manner (1 – 10) as a column of air pressure () from the lungs below flows through. This very rapid ordered closing and opening produced by the column of air is referred to as the mucosal wave. The lower edge opens first (2-3) followed by the upper edge thus letting air flow through (4-6). The air column that flows through creates a "Bernouli effect" which causes the lower edge to close (7-9) as it escapes upwards. The escaping "puffs of air" (10) are converted to sound which is then transformed into voice by vocal tract resonators. This diagram can be found in Anatomy and Physiology of Voice Production: Understanding How Voice is Produced.

Any change that affects this mucosal wave – stiffness of vocal fold layers, weakness or failure of closure, imbalance between R and L vocal folds from a lesion on one vocal fold – causes voice problems. (For more information, see Anatomy: How Breakdowns Result in Voice Disorders.