Genioglossus

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Genioglossus
Genioglossus.png
Extrinsic muscles of the tongue. Left side.
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Muscles of the tongue from below, with genioglossus visible at top
Details
Origin Superior part of mental spine of mandible (symphysis menti)
Insertion Underside of tongue and body of hyoid
Artery Lingual artery
Nerve Hypoglossal nerve
Actions Inferior fibers protrude the tongue, middle fibers depress the tongue, and its superior fibers draw the tip back and down
Identifiers
Latin musculus genioglossus
TA98 A05.1.04.101
TA2 2117
FMA 46690
Anatomical terms of muscle

The genioglossus is one of the paired extrinsic muscles of the tongue. It is a fan-shaped muscle that comprises the bulk of the body of the tongue. It arises from the mental spine of the mandible; it inserts onto the hyoid bone, and the bottom of the tongue. It is innervated by the hypoglossal nerve (cranial nerve XII). The genioglossus is the major muscle responsible for protruding (or sticking out) the tongue.

Contents

Structure

Genioglossus is the fan-shaped extrinsic tongue muscle that forms the majority of the body of the tongue. The muscle is paired, having a left and right portion, which are divided at the midline of the tongue by a septum made of connective tissue. [1]

Origin

The large part of the muscle arises from the mental spine of the mandible, [2] [3] but some fibers originate directly from the hyoid bone and connect vertically to the tongue. [1]

Insertion

Its insertions are the hyoid bone and the bottom of the tongue. [2] [3]

Innervation

The genioglossus is innervated by the hypoglossal nerve, [2] as are all muscles of the tongue except for the palatoglossus. [4]

Blood supply

Blood is supplied to the sublingual branch of the lingual artery, a branch of the external carotid artery. [2] [1]

Function

The left and right genioglossus muscles protrude the tongue (anteriorly, out of the mouth) and deviate it towards the opposite side. When acting together, the muscles protrude the tongue directly forward and depress the center of the tongue at its back. [2]

Clinical significance

Contraction of the genioglossus stabilizes and enlarges the portion of the upper airway that is most vulnerable to collapse. Relaxation of the genioglossus and geniohyoideus muscles, especially during REM sleep, is implicated in obstructive sleep apnea. [5] Given this connection, the mandible can be pulled forward to maximise the airway space, and prevent the tongue from sinking backwards under anaesthesia and obstructing the airway. [2]

The genioglossus is often used as a proxy to test the function of the hypoglossal nerve (CN XII), by asking a patient to stick out their tongue. Peripheral damage to the hypoglossal nerve can result in deviation of the tongue to the damaged side. If the tongue protrudes directly forward instead of deviating to either side, then the hypoglossal nerves are likely not injured. [1]

History

The name derives from the Greek words γένειον (geneion) meaning "chin", and γλῶσσα (glōssa) meaning "tongue." The earliest recorded mention is by Helkiah Crooke in the early seventeenth century. [6]

Other animals

The canine genioglossus muscle has been divided into horizontal and oblique compartments. [7]

Related Research Articles

<span class="mw-page-title-main">Otorhinolaryngology</span> Medical specialty

Otorhinolaryngology is a surgical subspecialty within medicine that deals with the surgical and medical management of conditions of the head and neck. Doctors who specialize in this area are called otorhinolaryngologists, otolaryngologists, head and neck surgeons, or ENT surgeons or physicians. Patients seek treatment from an otorhinolaryngologist for diseases of the ear, nose, throat, base of the skull, head, and neck. These commonly include functional diseases that affect the senses and activities of eating, drinking, speaking, breathing, swallowing, and hearing. In addition, ENT surgery encompasses the surgical management of cancers and benign tumors and reconstruction of the head and neck as well as plastic surgery of the face, scalp, and neck.

<span class="mw-page-title-main">Hypoglossal nerve</span> Cranial nerve XII, for the tongue

The hypoglossal nerve, also known as the twelfth cranial nerve, cranial nerve XII, or simply CN XII, is a cranial nerve that innervates all the extrinsic and intrinsic muscles of the tongue except for the palatoglossus, which is innervated by the vagus nerve. CN XII is a nerve with a sole motor function. The nerve arises from the hypoglossal nucleus in the medulla as a number of small rootlets, pass through the hypoglossal canal and down through the neck, and eventually passes up again over the tongue muscles it supplies into the tongue.

<span class="mw-page-title-main">Hyoid bone</span> Bone situated in the neck between the chin and the thyroid cartilage

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 between the base of the mandible and the third cervical vertebra.

<span class="mw-page-title-main">Infrahyoid muscles</span> Group of muscles

The infrahyoid muscles, or strap muscles, are a group of four pairs of muscles in the anterior (frontal) part of the neck. The four infrahyoid muscles are the sternohyoid, sternothyroid, thyrohyoid and omohyoid muscles.

<span class="mw-page-title-main">Digastric muscle</span> Small muscle located under the jaw in mammals

The digastric muscle is a bilaterally paired suprahyoid muscle located under the jaw. Its posterior belly is attached to the mastoid notch of temporal bone, and its anterior belly is attached to the digastric fossa of mandible; the two bellies are united by an intermediate tendon which is held in a loop that attaches to the hyoid bone. The anterior belly is innervated via the mandibular nerve, and the posterior belly is innervated via the facial nerve. It may act to depress the mandible or elevate the hyoid bone.

<span class="mw-page-title-main">Geniohyoid muscle</span> Muscle of the head

The geniohyoid muscle is a narrow paired muscle situated superior to the medial border of the mylohyoid muscle. It is named for its passage from the chin to the hyoid bone.

<span class="mw-page-title-main">Stylohyoid muscle</span> Muscle

The stylohyoid muscle is one of the suprahyoid muscles. Its originates from the styloid process of the temporal bone; it inserts onto hyoid bone. It is innervated by a branch of the facial nerve. It acts draw the hyoid bone upwards and backwards.

<span class="mw-page-title-main">Thyrohyoid muscle</span> Neck muscle that depresses the hyoid bone and elevates the larynx

The thyrohyoid muscle is a small skeletal muscle of the neck. Above, it attaches onto the greater cornu of the hyoid bone; below, it attaches onto the oblique line of the thyroid cartilage. It is innervated by fibres derived from the cervical spinal nerve 1 that run with the hypoglossal nerve to reach this muscle. The thyrohyoid muscle depresses the hyoid bone and elevates the larynx during swallowing. By controlling the position and shape of the larynx, it aids in making sound.

<span class="mw-page-title-main">Hyoglossus</span> Muscle

The hyoglossus is a thin and quadrilateral extrinsic muscle of the tongue. It originates from the hyoid bone; it inserts onto the side of the tongue. It is innervated by the hypoglossal nerve. It acts to depress and retract the tongue.

<span class="mw-page-title-main">Styloglossus</span>

The styloglossus muscle is a bilaterally paired muscle of the tongue. It originates at the styloid process of the temporal bone. It inserts onto the side of the tongue. It acts to elevate and retract the tongue. It is innervated by the hypoglossal nerve.

<span class="mw-page-title-main">Palatoglossus muscle</span> Muscle of the soft palate

The palatoglossal muscle is a muscle of the soft palate and an extrinsic muscle of the tongue. Its surface is covered by oral mucosa and forms the visible palatoglossal arch.

<span class="mw-page-title-main">Inferior longitudinal muscle of tongue</span> Intrinsic muscle of the tongue

The inferior longitudinal muscle of tongue is an intrinsic muscle of the tongue. It is situated on the under surface of the tongue between the genioglossus and hyoglossus. It is innervated by the hypoglossal nerve. Its contraction shortens and thickens the tongue.

<span class="mw-page-title-main">Superior pharyngeal constrictor muscle</span> Muscle

The superior pharyngeal constrictor muscle is a quadrilateral muscle of the pharynx. It is the uppermost and thinnest of the three pharyngeal constrictors.

<span class="mw-page-title-main">Chondroglossus</span> Muscle of the tongue

The chondroglossus muscle is a muscle of the tongue. It arises from the medial side of the lesser horn of the hyoid bone, before blending with intrinsic muscles of the tongue. It is supplied by the hypoglossal nerve.

<span class="mw-page-title-main">Lingual artery</span>

The lingual artery arises from the external carotid artery between the superior thyroid artery and facial artery. It can be located easily in the tongue.

<span class="mw-page-title-main">Temporal styloid process</span> Part of the temporal bone

The temporal styloid process is a slender bony process of the temporal bone extending downward and forward from the undersurface of the temporal bone just below the ear. The styloid process gives attachments to several muscles, and ligaments.

<span class="mw-page-title-main">Sublingual space</span>

The sublingual space is a fascial space of the head and neck. It is a potential space located below the mouth and above the mylohyoid muscle, and is part of the suprahyoid group of fascial spaces.

Fascial spaces are potential spaces that exist between the fasciae and underlying organs and other tissues. In health, these spaces do not exist; they are only created by pathology, e.g. the spread of pus or cellulitis in an infection. The fascial spaces can also be opened during the dissection of a cadaver. The fascial spaces are different from the fasciae themselves, which are bands of connective tissue that surround structures, e.g. muscles. The opening of fascial spaces may be facilitated by pathogenic bacterial release of enzymes which cause tissue lysis. The spaces filled with loose areolar connective tissue may also be termed clefts. Other contents such as salivary glands, blood vessels, nerves and lymph nodes are dependent upon the location of the space. Those containing neurovascular tissue may also be termed compartments.

Hyoid suspension, also known as hyoid myotomy and suspension or hyoid advancement, is a surgical procedure or sleep surgery in which the hyoid bone and its muscle attachments to the tongue and airway are pulled forward with the aim of increasing airway size and improving airway stability in the retrolingual and hypopharyngeal airway. The horseshoe shaped hyoid bone sits directly below the base of tongue with the arms of the bone flanking the airway. Hyoid suspension is typically performed as a treatment for obstructive sleep apnea (OSA). This procedure is frequently performed with a uvulopalatopharyngoplasty (UPPP) which targets sites of obstruction higher in the airway. Typically, a hyoid suspension is considered successful when the patient's apnea-hypopnea index is significantly reduced after surgery.

The hypoglossal nerve stimulator is a novel strategy for the treatment of obstructive sleep apnea. It has been gaining popularity over the last few decades and was approved in Europe in 2013 and the Food and Drug Administration (FDA) in April 2014. The purpose of the hypoglossal nerve stimulator is to relieve tongue base obstruction during sleep by stimulating the tongue to protrude during inspiration.

References

  1. 1 2 3 4 Drake, Richard L.; Vogl, Wayne; Tibbitts, Adam W.M. Mitchell (2005). Gray's anatomy for students. Philadelphia: Elsevier/Churchill Livingstone. pp. 991–2. ISBN   978-0-443-06612-2.
  2. 1 2 3 4 5 6 Susan Standring; Neil R. Borley; et al., eds. (2008). Gray's anatomy : the anatomical basis of clinical practice (40th ed.). London: Churchill Livingstone. pp. 503–5. ISBN   978-0-8089-2371-8.
  3. 1 2 Singh, Inderbir (2009). Essentials of anatomy (2nd ed.). New Delhi: Jaypee Bros. p. 348. ISBN   978-81-8448-461-8.[ permanent dead link ]
  4. ↑ M. J. T. Fitzgerald; Gregory Gruener; Estomih Mtui (2012). Clinical Neuroanatomy and Neuroscience. Saunders/Elsevier. p. 216. ISBN   978-0-7020-4042-9.
  5. ↑ den Herder, Cindy; Schmeck, Joachim; Appelboom, Dick J K; de Vries, Nico (2004). "Risks of general anaesthesia in people with obstructive sleep apnoea". BMJ. 329 (7472): 955–9. doi:10.1136/bmj.329.7472.955. PMC   524108 . PMID   15499112.
  6. ↑ "genioglossus - definition of genioglossus in English | Oxford Dictionaries". Oxford Dictionaries | English. Archived from the original on March 26, 2017. Retrieved 2017-03-26.
  7. ↑ Mu, Liancai; Sanders, Ira (2000). "Neuromuscular specializations of the pharyngeal dilator muscles: II. Compartmentalization of the canine genioglossus muscle". The Anatomical Record. 260 (3): 308–25. doi:10.1002/1097-0185(20001101)260:3<308::aid-ar70>3.0.co;2-n. PMID   11066041.
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