The genioglossus is a muscle in the human jaw that both keeps the airway open and enables the tongue to stick out and retract. It extends from the back of the lower jaw to the tongue in a fan shape that spans the width of the palate. Most of the time, the muscle is contracted and engaged, even when asleep. Relaxation of the muscle can lead to airway obstruction, which can cause snoring and sleep disorders, such as sleep apnea. A surgical procedure known as “genioglossus advancement” can correct most of the sleeping disorders connected to the muscle.
The genioglossus falls within the large category of muscles of the head and neck, but it is properly considered a muscle of the tongue specifically. It is located in the lower mandible of the jaw, near the back of the chin. It is responsible for tongue movement, particularly the ability to stick out the tongue. It is not, however, considered a muscle of facial expression. It does not control any nerves or muscle movements outside of the tongue.
One of the most important functions of the genioglossus is the maintenance of an open airway. The muscle does not itself control the airway — both the upper and lower airways function with the aid of their own set of muscles — but it plays a supporting role in airway maintenance. If the genioglossus is not functioning properly, it can allow the tongue to move into the path of the airway, causing blockage or obstruction.
Snoring is the most common sign of a weakened genioglossus. Snoring is usually caused by the tongue slipping back into the throat, which would not happen if the muscle was properly constricted. A weakened genioglossus is not in and of itself problematic, and snoring is not always a condition warranting treatment. If the muscle is very weak, however, or if it is shorter or positioned farther back in the jaw than normal, there can be serious consequences, and medical attention is often required.
A weakened genioglossus is often to blame for sleep apnea, a sleep disorder marked by uneven breathing and restlessness owing to inconsistent levels oxygen reaching the brain. Surgery on the genioglossus can, in many cases, relieve or cure sleep apnea. A surgeon can bring the muscle forward through what is known as a genioglossus advancement procedure. This will strengthen the muscle’s pressure on the tongue, and can help keep the airway open and breathing consistent during sleep.