The hyoid bone (lingual bone or tongue-bone) () is a

horseshoe-shaped Many shapes have metaphorical names, i.e., their names are metaphors: these shapes are named after a most common object that has it. For example, "U-shape" is a shape that resembles the letter U, a bell-shaped curve has the shape of the vertical ...

bone A bone is a Stiffness, rigid Organ (biology), organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red blood cell, red and white blood cells, store minerals, provid ...

situated in the anterior midline of the

neck The neck is the part of the body on many vertebrates that connects the head with the torso. The neck supports the weight of the head and protects the nerves that carry sensory and motor information from the brain down to the rest of the body. In ...

between the

chin The chin is the forward pointed part of the anterior mandible (List_of_human_anatomical_regions#Regions, mental region) below the lower lip. A fully developed human skull has a chin of between 0.7 cm and 1.1 cm. Evolution The presence of a we ...

and the

thyroid cartilage The thyroid cartilage is the largest of the nine cartilages that make up the ''laryngeal skeleton'', the cartilage structure in and around the trachea that contains the larynx. It does not completely encircle the larynx (only the cricoid cartilage ...

. At rest, it lies between the base of the

mandible In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower tooth, teeth in place. The mandible sits beneath the maxilla. It is the only movabl ...

and the third

cervical vertebra In tetrapods, cervical vertebrae (singular: vertebra) are the vertebrae of the neck, immediately below the skull. Truncal vertebrae (divided into thoracic and lumbar vertebrae in mammals) lie caudal (toward the tail) of cervical vertebrae. In sau ...

. Unlike other bones, the hyoid is only distantly

articulated An articulated vehicle is a vehicle which has a permanent or semi-permanent pivot joint in its construction, allowing it to turn more sharply. There are many kinds, from heavy equipment to buses, trams and trains. Steam locomotives were someti ...

to other bones by muscles or ligaments. It is the only bone in the human body that is not connected to any other bones nearby. The hyoid is anchored by muscles from the anterior, posterior and inferior directions, and aids in tongue movement and swallowing. The hyoid bone provides attachment to the muscles of the floor of the mouth and the tongue above, the

larynx The larynx (), commonly called the voice box, is an organ in the top of the neck involved in breathing, producing sound and protecting the trachea against food aspiration. The opening of larynx into pharynx known as the laryngeal inlet is about ...

below, and the

epiglottis The epiglottis is a leaf-shaped flap in the throat that prevents food and water from entering the trachea and the lungs. It stays open during breathing, allowing air into the larynx. During swallowing, it closes to prevent aspiration of food int ...

and

pharynx The pharynx (plural: pharynges) is the part of the throat behind the mouth and nasal cavity, and above the oesophagus and trachea (the tubes going down to the stomach and the lungs). It is found in vertebrates and invertebrates, though its struc ...

behind. Its name is derived .

Structure

The hyoid bone is classed as an

irregular bone The irregular bones are bones which, from their peculiar form, cannot be grouped as long, short, flat or sesamoid bones. Irregular bones serve various purposes in the body, such as protection of nervous tissue (such as the vertebrae protect the sp ...

and consists of a central part called the

body Body may refer to: In science * Physical body, an object in physics that represents a large amount, has mass or takes up space * Body (biology), the physical material of an organism * Body plan, the physical features shared by a group of anima ...

, and two pairs of horns, the greater and lesser horns.

Body

The body of the hyoid bone is the central part of the hyoid bone. *At the front, the body is convex and directed forward and upward. * It is crossed in its upper half by a well-marked transverse ridge with a slight downward convexity, and in many cases a vertical median ridge divides it into two lateral halves. * The portion of the vertical ridge above the transverse line is present in a majority of specimens, but the lower portion is evident only in rare cases. * The anterior surface gives insertion to the

geniohyoid muscle The geniohyoid muscle is a narrow muscle situated superior to the medial border of the mylohyoid muscle. It is named for its passage from the chin ("genio-" is a standard prefix for "chin") to the hyoid bone. Structure It arises from the infe ...

in the greater part of its extent both above and below the transverse ridge; a portion of the origin of the

hyoglossus The hyoglossus, thin and quadrilateral, arises from the side of the body and from the whole length of the greater cornu of the hyoid bone, and passes almost vertically upward to enter the side of the tongue, between the styloglossus and the infe ...

notches the lateral margin of the geniohyoid attachment. * Below the transverse ridge the mylohyoid,

sternohyoid The sternohyoid muscle is a thin, narrow muscle attaching the hyoid bone to the sternum. It is one of the paired strap muscles of the infrahyoid muscles. It is supplied by the ansa cervicalis. It depresses the hyoid bone. Structure The sternohy ...

, and omohyoid are inserted. * At the back, the smooth, concave, directed backward and downward, and separated from the

by the

hyothyroid membrane The thyrohyoid membrane (or hyothyroid membrane) is a broad, fibro-elastic sheet of the larynx. It connects the upper border of the thyroid cartilage to the hyoid bone. Structure The thyrohyoid membrane is attached below to the upper border of ...

and a quantity of

loose areolar tissue Loose connective tissue, sometimes called areolar tissue, is a cellular connective tissue with thin and relatively sparse collagen fibers. Its ground substance occupies more volume than the fibers do. It has a viscous to gel-like consistenc ...

; a

bursa ( grc-gre, Προῦσα, Proûsa, Latin: Prusa, ota, بورسه, Arabic:بورصة) is a city in northwestern Turkey and the administrative center of Bursa Province. The fourth-most populous city in Turkey and second-most populous in the ...

intervenes between it and the hyothyroid membrane. * Above, the body is rounded, and gives attachment to the hyothyroid membrane and some

aponeurotic An aponeurosis (; plural: ''aponeuroses'') is a type or a variant of the deep fascia, in the form of a sheet of pearly-white fibrous tissue that attaches sheet-like muscles needing a wide area of attachment. Their primary function is to join musc ...

fibers of the

genioglossus The genioglossus is one of the paired extrinsic muscles of the tongue. 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 ma ...

. * Below, the body affords insertion medially to the sternohyoid and laterally to the omohyoid and occasionally a portion of the

thyrohyoid The thyrohyoid muscle is a small skeletal muscle on the neck. It originates from the lamina of the thyroid cartilage, and inserts into the greater cornu of the hyoid bone. It is supplied by the hypoglossal nerve, and a branch of the ventral rami o ...

. It also gives attachment to the Levator glandulae thyreoideae, when this muscle is present.

Horns

The greater and lesser horns ( la, cornua) are two sections of bone that project from each side of the hyoid. The greater horns project backward from the outer borders of the body; they are flattened from above downward and taper to their end, which is a bony

tubercle In anatomy, a tubercle (literally 'small tuber', Latin for 'lump') is any round nodule, small eminence, or warty outgrowth found on external or internal organs of a plant or an animal. In plants A tubercle is generally a wart-like projection ...

connecting to the

lateral thyrohyoid ligament The lateral thyrohyoid ligament (lateral hyothyroid ligament) is a round elastic cord, which forms the posterior border of the thyrohyoid membrane and passes between the tip of the superior cornu of the thyroid cartilage and the extremity of the gr ...

. The upper surface of the greater horns are rough and close to its lateral border, and facilitates muscular attachment. The largest of muscles that attach to the upper surface of the greater horns are the

and the

middle pharyngeal constrictor The middle pharyngeal constrictor is a fan-shaped muscle located in the neck. It is one of three pharyngeal constrictors. Similarly to the superior and inferior pharyngeal constrictor muscles, the middle pharyngeal constrictor is innervated by a ...

, which extend along the whole length of the horns; the

digastric muscle The digastric muscle (also digastricus) (named ''digastric'' as it has two 'bellies') is a small muscle located under the jaw. The term "digastric muscle" refers to this specific muscle. However, other muscles that have two separate muscle bellie ...

and

stylohyoid muscle The stylohyoid muscle is a slender muscle, lying anterior and superior of the posterior belly of the digastric muscle. It is one of the suprahyoid muscles. It shares this muscle's innervation by the facial nerve, and functions to draw the hyoid ...

have small insertions in front of these near the junction of the body with the horns. To the medial border the

thyrohyoid membrane The thyrohyoid membrane (or hyothyroid membrane) is a broad, fibro-elastic sheet of the larynx. It connects the upper border of the thyroid cartilage to the hyoid bone. Structure The thyrohyoid membrane is attached below to the upper border of ...

is attached, while the anterior half of the lateral border gives insertion to the

thyrohyoid muscle The thyrohyoid muscle is a small skeletal muscle on the neck. It originates from the lamina of the thyroid cartilage, and inserts into the greater cornu of the hyoid bone. It is supplied by the hypoglossal nerve, and a branch of the ventral rami ...

. The lesser horns are two small, conical eminences, attached by their bases to the angles of junction between the body and greater horns of the hyoid bone. They are connected to the body of the bone by fibrous tissue, and occasionally to the greater horns by distinct diarthrodial

joint A joint or articulation (or articular surface) is the connection made between bones, ossicles, or other hard structures in the body which link an animal's skeletal system into a functional whole.Saladin, Ken. Anatomy & Physiology. 7th ed. McGraw ...

s, which usually persist throughout life, but occasionally become

ankylosed Ankylosis is a stiffness of a joint due to abnormal adhesion and rigidity of the bones of the joint, which may be the result of injury or disease. The rigidity may be complete or partial and may be due to inflammation of the tendinous or muscula ...

. The lesser horns are situated in the line of the transverse ridge on the body and appear to be continuations of it. The apex of each horn gives attachment to the

stylohyoid ligament The stylohyoid ligament is a ligament that connects the hyoid bone to the temporal styloid process (of the temporal bone of the skull). Structure The stylohyoid ligament connects the lesser horn of hyoid bone to the styloid process of the ...

; the chondroglossus rises from the medial side of the base.

Development

The second

pharyngeal arch The pharyngeal arches, also known as visceral arches'','' are structures seen in the embryonic development of vertebrates that are recognisable precursors for many structures. In fish, the arches are known as the branchial arches, or gill arch ...

, also called the hyoid arch, gives rise to the lesser cornu of the hyoid and the upper part of the body of the hyoid. The cartilage of the third pharyngeal arch forms the greater cornu of the hyoid and the lower portion of the body of the hyoid. The hyoid is

ossified Ossification (also called osteogenesis or bone mineralization) in bone remodeling is the process of laying down new bone material by Cell (biology), cells named osteoblasts. It is synonymous with bone tissue formation. There are two processes ...

from six centers: two for the body, and one for each cornu. Ossification commences in the greater cornua toward the end of

fetal development Prenatal development () includes the development of the embryo and of the fetus during a viviparous animal's gestation. Prenatal development starts with fertilization, in the germinal stage of embryonic development, and continues in fetal devel ...

, in the hyoid body shortly afterward, and in the lesser cornua during the first or second year after birth. Until middle age the connection between the body and greater cornu is

fibrous Fiber or fibre (from la, fibra, links=no) is a natural or artificial substance that is significantly longer than it is wide. Fibers are often used in the manufacture of other materials. The strongest engineering materials often incorporate ...

. In early life the outer borders of the body are connected to the greater horns by synchondroses; after middle life usually by bony union.

Blood supply

Blood is supplied to the hyoid bone via the

lingual artery 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. Structure The lingual artery first branches off from the external carotid artery. It runs ob ...

, which runs down from the

tongue The tongue is a muscular organ (anatomy), organ in the mouth of a typical tetrapod. It manipulates food for mastication and swallowing as part of the digestive system, digestive process, and is the primary organ of taste. The tongue's upper surfa ...

to the greater horns of the bone. The suprahyoid branch of the lingual artery runs along the upper border of the hyoid bone and supplies blood to the attached muscles.

Function

The hyoid bone is present in many

mammal Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...

s. It allows a wider range of tongue, pharyngeal and laryngeal movements by bracing these structures alongside each other in order to produce variation. Its descent in living creatures is not unique to ''

Homo sapiens Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, culture, ...

'', and does not allow the production of a wide range of sounds: with a lower larynx, men do not produce a wider range of sounds than women and two-year-old babies. Moreover, the larynx position of Neanderthals was not a handicap to producing speech sounds. The discovery of a modern-looking hyoid bone of a

Neanderthal Neanderthals (, also ''Homo neanderthalensis'' and erroneously ''Homo sapiens neanderthalensis''), also written as Neandertals, are an extinct species or subspecies of archaic humans who lived in Eurasia until about 40,000 years ago. While th ...

man in the

Kebara Cave Kebara Cave ( he, מערת כבארה, Me'arat Kebbara, ar, مغارة الكبارة, Mugharat al-Kabara) is a limestone cave locality in Wadi Kebara, situated at above mean sea level, above sea level on the western escarpment of the Mount Car ...

Israel Israel (; he, יִשְׂרָאֵל, ; ar, إِسْرَائِيل, ), officially the State of Israel ( he, מְדִינַת יִשְׂרָאֵל, label=none, translit=Medīnat Yīsrāʾēl; ), is a country in Western Asia. It is situated ...

led its discoverers to argue that the Neanderthals had a descended

, and thus human-like

speech Speech is a human vocal communication using language. Each language uses Phonetics, phonetic combinations of vowel and consonant sounds that form the sound of its words (that is, all English words sound different from all French words, even if ...

capabilities. However, other researchers have claimed that the morphology of the hyoid is not indicative of the larynx's position. Recent research has indicated that the hyoid bone may have significant involvement in the ability to swallow. It has been hypothesized that the mammalian hyoid bone evolved in conjunction with the development of

lactation Lactation describes the secretion of milk from the mammary glands and the period of time that a mother lactates to feed her young. The process naturally occurs with all sexually mature female mammals, although it may predate mammals. The proces ...

, thus allowing babies to suckle milk. It is necessary to take into consideration the skull base, the mandible and the cervical vertebrae and a cranial reference plane.

Muscle attachments

A large number of muscles attach to the hyoid: *Superior **

Middle pharyngeal constrictor muscle The middle pharyngeal constrictor is a fan-shaped muscle located in the neck. It is one of three pharyngeal constrictors. Similarly to the superior and inferior pharyngeal constrictor muscles, the middle pharyngeal constrictor is innervated by a ...

** Hyoglossus muscle **

Genioglossus The genioglossus is one of the paired extrinsic muscles of the tongue. 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 ma ...

Intrinsic muscles of the tongue The tongue is a muscular organ in the mouth of a typical tetrapod. It manipulates food for mastication and swallowing as part of the digestive process, and is the primary organ of taste. The tongue's upper surface (dorsum) is covered by tast ...

Suprahyoid muscles The suprahyoid muscles are four muscles located above the hyoid bone in the neck. They are the digastric, stylohyoid, geniohyoid, and mylohyoid muscle, mylohyoid muscles. They are all pharyngeal muscles, with the exception of the geniohyoid muscle. ...

***

Digastric muscle The digastric muscle (also digastricus) (named ''digastric'' as it has two 'bellies') is a small muscle located under the jaw. The term "digastric muscle" refers to this specific muscle. However, other muscles that have two separate muscle bellie ...

***

Stylohyoid muscle The stylohyoid muscle is a slender muscle, lying anterior and superior of the posterior belly of the digastric muscle. It is one of the suprahyoid muscles. It shares this muscle's innervation by the facial nerve, and functions to draw the hyoid ...

***

Geniohyoid muscle The geniohyoid muscle is a narrow muscle situated superior to the medial border of the mylohyoid muscle. It is named for its passage from the chin ("genio-" is a standard prefix for "chin") to the hyoid bone. Structure It arises from the infe ...

***

Mylohyoid muscle The mylohyoid muscle or diaphragma oris is a paired muscle of the neck. It runs from the mandible to the hyoid bone, forming the floor of the oral cavity of the mouth. It is named after its two attachments near the molar teeth. It forms the floor ...

*Inferior **

Thyrohyoid muscle The thyrohyoid muscle is a small skeletal muscle on the neck. It originates from the lamina of the thyroid cartilage, and inserts into the greater cornu of the hyoid bone. It is supplied by the hypoglossal nerve, and a branch of the ventral rami ...

Omohyoid muscle The omohyoid muscle is a muscle that depresses the hyoid. It is located in the front of the neck, and consists of two bellies separated by an intermediate tendon. The omohyoid muscle is proximally attached to the scapula and distally attached to th ...

Sternohyoid muscle The sternohyoid muscle is a thin, narrow muscle attaching the hyoid bone to the sternum. It is one of the paired strap muscles of the infrahyoid muscles. It is supplied by the ansa cervicalis. It depresses the hyoid bone. Structure The sternohy ...

Sternothyroid muscle The sternothyroid muscle, or sternothyroideus, is an infrahyoid muscle in the neck. It acts to depress the hyoid bone. It is below the sternohyoid muscle. It is shorter and wider than the sternohyoid. Structure The sternothyroid arises from the ...

File:Gray380.png,

Muscle Skeletal muscles (commonly referred to as muscles) are organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other types of muscl ...

s of the

and

cheek The cheeks ( la, buccae) constitute the area of the face below the eyes and between the nose and the left or right ear. "Buccal" means relating to the cheek. In humans, the region is innervated by the buccal nerve. The area between the inside ...

File:Gray385.png, Muscles of the

. Lateral view.

Clinical significance

The hyoid bone is important to a number of physiological functions, including breathing, swallowing and speech. It is also thought to play a key role in keeping the upper airway open during sleep, and as such, the development and treatment of

obstructive sleep apnea Obstructive sleep apnea (OSA) is the most common sleep-related breathing disorder and is characterized by recurrent episodes of complete or partial obstruction of the upper airway leading to reduced or absent breathing during sleep. These episod ...

(OSA; characterized by repetitive collapse of the upper airway during sleep). A mechanistic involvement of the hyoid bone in OSA is supported by numerous studies demonstrating that a more inferiorly positioned hyoid bone is strongly associated with the presence and severity of the disorder. Movement of the hyoid bone is also thought to be important in modifying upper airway properties, which was recently demonstrated in computer model simulations. A

surgical procedure Surgery ''cheirourgikē'' (composed of χείρ, "hand", and ἔργον, "work"), via la, chirurgiae, meaning "hand work". is a medical specialty that uses operative manual and instrumental techniques on a person to investigate or treat a pat ...

that aims to potentially increase and improve the airway is called

hyoid suspension 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 ai ...

. Due to its position, the hyoid bone is not easily susceptible to fracture. In a suspected case of murder or physical abuse of an adult, a fractured hyoid strongly indicates throttling or

strangulation Strangling is compression of the neck that may lead to unconsciousness or death by causing an increasingly hypoxic state in the brain. Fatal strangling typically occurs in cases of violence, accidents, and is one of two main ways that hanging ...

. In children and adolescents (in whom the hyoid bone is still flexible because

ossification Ossification (also called osteogenesis or bone mineralization) in bone remodeling is the process of laying down new bone material by cells named osteoblasts. It is synonymous with bone tissue formation. There are two processes resulting in t ...

is yet to be completed) fracture may not occur even after serious trauma.

Other animals

The hyoid bone is derived from the lower half of the second

gill arch Branchial arches, or gill arches, are a series of bony "loops" present in fish, which support the gills. As gills are the primitive condition of vertebrates, all vertebrate embryos develop pharyngeal arches, though the eventual fate of these arc ...

fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of li ...

, which separates the first gill slit from the

spiracle Spiracle or spiraculum may refer to: * Spiracle (arthropods), opening in the exoskeletons of some arthropods * Spiracle (vertebrates), openings on the surface of some vertebrates * Spiraculum, a genus of land snails in family Cyclophoridae Cycl ...

, and is often called the ''

hyoid arch The pharyngeal arches, also known as visceral arches'','' are structures seen in the embryonic development of vertebrates that are recognisable precursors for many structures. In fish, the arches are known as the branchial arches, or gill arc ...

''. In many vertebrates, it also incorporates elements of other gill arches, and has a correspondingly greater number of cornua.

Amphibian Amphibians are tetrapod, four-limbed and ectothermic vertebrates of the Class (biology), class Amphibia. All living amphibians belong to the group Lissamphibia. They inhabit a wide variety of habitats, with most species living within terres ...

s and

reptile Reptiles, as most commonly defined are the animals in the class Reptilia ( ), a paraphyletic grouping comprising all sauropsids except birds. Living reptiles comprise turtles, crocodilians, squamates (lizards and snakes) and rhynchocephalians ( ...

s may have many cornua, while mammals (including humans) have two pairs, and

bird Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweigh ...

s only one. In birds, and some reptiles, the body of the hyoid is greatly extended forward, creating a solid bony support for the

. The howler monkey ''

Alouatta Howler monkeys (genus ''Alouatta'', monotypic in subfamily Alouattinae) are the most widespread primate genus in the Neotropics and are among the largest of the platyrrhines along with the muriquis (''Brachyteles''), the spider monkeys (''Atele ...

'' has a pneumatized hyoid bone, one of the few cases of postcranial pneumatization of bones outside

Saurischia Saurischia ( , meaning "reptile-hipped" from the Greek ' () meaning 'lizard' and ' () meaning 'hip joint') is one of the two basic divisions of dinosaurs (the other being Ornithischia), classified by their hip structure. Saurischia and Ornithis ...

. In

mammals Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...

, the hyoid often determines whether one can roar. If the hyoid is incompletely

(for example:

lions The lion (''Panthera leo'') is a large cat of the genus ''Panthera'' native to Africa and India. It has a muscular, broad-chested body; short, rounded head; round ears; and a hairy tuft at the end of its tail. It is sexually dimorphic; adult ...

) it allows the animal to roar, but not purr. If the hyoid is completely ossified (for example:

cheetahs The cheetah (''Acinonyx jubatus'') is a large cat native to Africa and central Iran. It is the fastest land animal, estimated to be capable of running at with the fastest reliably recorded speeds being , and as such has evolved specialized ...

), it does not allow the animal to roar, but instead will allow the animal to purr and meow, as seen in house cats (lions, cheetahs and house cats all belong to the family

Felidae Felidae () is the family of mammals in the order Carnivora colloquially referred to as cats, and constitutes a clade. A member of this family is also called a felid (). The term "cat" refers both to felids in general and specifically to the ...

). In veterinary anatomy, the term

hyoid apparatus The hyoid apparatus is the collective term used in veterinary anatomy for the bones which suspend the tongue and larynx. It consists of pairs of stylohyoid, thyrohyoid, epihyoid and ceratohyoid bones, and a single basihyoid bone. The hyoid appara ...

is the collective term used to refer to the

s of the

—a pair of stylohyoidea, a pair of thyrohyoidea, and unpaired basihyoideum—and associated, upper-

gular Gular is of or pertaining to the throat In vertebrate anatomy, the throat is the front part of the neck, internally positioned in front of the vertebrae. It contains the pharynx and larynx. An important section of it is the epiglottis, separatin ...

connective tissues. In humans, the single hyoid bone is an equivalent of the hyoid apparatus.

References

External links

* () {{DEFAULTSORT:Hyoid Bone Human head and neck Irregular bones