Genioglossus
Encyclopedia
The genioglossus is a muscle
of the human body
which runs from the chin to the tongue
. The genioglossus is the major muscle responsible for protruding (or sticking out) the tongue.
. Its origin is the mental spine
of the mandible and its insertions are the hyoid bone
and the dorsum of the tongue. Innervated by the hypoglossal nerve
(CN XII), it depresses and protrudes the tongue.
A relaxation of the genioglossus and geniohyoideus muscles, especially during REM sleep, is implicated in Obstructive Sleep Apnea
(OSA.)
Peripheral damage to the hypoglossal nerve can result in deviation of the tongue to the damaged side.
Muscle
Muscle is a contractile tissue of animals and is derived from the mesodermal layer of embryonic germ cells. Muscle cells contain contractile filaments that move past each other and change the size of the cell. They are classified as skeletal, cardiac, or smooth muscles. Their function is to...
of the human body
Human body
The human body is the entire structure of a human organism, and consists of a head, neck, torso, two arms and two legs.By the time the human reaches adulthood, the body consists of close to 100 trillion cells, the basic unit of life...
which runs from the chin to the tongue
Tongue
The tongue is a muscular hydrostat on the floors of the mouths of most vertebrates which manipulates food for mastication. It is the primary organ of taste , as much of the upper surface of the tongue is covered in papillae and taste buds. It is sensitive and kept moist by saliva, and is richly...
. The genioglossus is the major muscle responsible for protruding (or sticking out) the tongue.
Structure
Genioglossus is the fan-shaped extrinsic tongue muscle that forms the majority of the body of the tongueTongue
The tongue is a muscular hydrostat on the floors of the mouths of most vertebrates which manipulates food for mastication. It is the primary organ of taste , as much of the upper surface of the tongue is covered in papillae and taste buds. It is sensitive and kept moist by saliva, and is richly...
. Its origin is the mental spine
Mental spine
A mental spine is a small projection of bone on the posterior aspect of the mandible in the midline. There are usually 4 mental spines: 2 superior and 2 inferior. Collectively they are also known as the genial tubercle, genial apophysis and the Latin name spinae mentalis...
of the mandible and its insertions are the hyoid bone
Hyoid bone
The hyoid bone is a horseshoe-shaped bone situated in the anterior midline of the neck between the chin and the thyroid cartilage. At rest, it lies at the level of the base of the mandible in the front and the third cervical vertebra behind.Unlike other bones, the hyoid is only distantly...
and the dorsum of the tongue. Innervated by the hypoglossal nerve
Hypoglossal nerve
The hypoglossal nerve is the twelfth cranial nerve , leading to the tongue. The nerve arises from the hypoglossal nucleus and emerges from the medulla oblongata in the preolivary sulcus separating the olive and the pyramid. It then passes through the hypoglossal canal...
(CN XII), it depresses and protrudes the tongue.
Clinical relevance
Contraction of the genioglossus stabilizes and enlarges the portion of the upper airway that is most vulnerable to collapse.A relaxation of the genioglossus and geniohyoideus muscles, especially during REM sleep, is implicated in Obstructive Sleep Apnea
Obstructive sleep apnea
Obstructive sleep apnea or obstructive sleep apnea syndrome is the most common type of sleep apnea and is caused by obstruction of the upper airway. It is characterized by repetitive pauses in breathing during sleep, despite the effort to breathe, and is usually associated with a reduction in...
(OSA.)
Peripheral damage to the hypoglossal nerve can result in deviation of the tongue to the damaged side.