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

bone A bone is a rigid organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red and white blood cells, store minerals, provide structure and support for the body, ...

situated in the anterior midline of the

neck The neck is the part of the body in many vertebrates that connects the head to the torso. It supports the weight of the head and protects the nerves that transmit sensory and motor information between the brain and the rest of the body. Addition ...

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. At rest, it lies between the base of the

mandible In jawed vertebrates, the mandible (from the Latin ''mandibula'', 'for chewing'), lower jaw, or jawbone is a bone that makes up the lowerand typically more mobilecomponent of the mouth (the upper jaw being known as the maxilla). The jawbone i ...

and the third cervical vertebra. Unlike other bones, the hyoid is only distantly articulated to other bones by muscles or ligaments. It is the only bone in the human body that is not connected to any other bones. 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 (anatomy), 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 ...

below, and the epiglottis and

pharynx The pharynx (: pharynges) is the part of the throat behind the human mouth, mouth and nasal cavity, and above the esophagus and trachea (the tubes going down to the stomach and the lungs respectively). It is found in vertebrates and invertebrates ...

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 ...

and consists of a central part called the body, 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 in the greater part of its extent both above and below the transverse ridge; a portion of the origin of the hyoglossus notches the lateral margin of the geniohyoid attachment. * Below the transverse ridge the mylohyoid, sternohyoid, and omohyoid are inserted. * At the back, the smooth, concave, directed backward and downward, and separated from the epiglottis by the hyothyroid membrane and a quantity of loose areolar tissue; a

bursa Bursa () 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 Marmara Region, Bursa is one of the industrial centers of the country. Most of ...

intervenes between it and the hyothyroid membrane. * Above, the body is rounded, and gives attachment to the hyothyroid membrane and some aponeurotic fibers of the genioglossus. * Below, the body affords insertion medially to the sternohyoid and laterally to the omohyoid and occasionally a portion of the thyrohyoid. It also gives attachment to the Levator glandulae thyreoideae, when this muscle is present.

Horns

The greater and lesser horns () are two sections of bone that project from each side of the hyoid.

Greater horns

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 connecting to the lateral thyrohyoid ligament. 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 hyoglossus and the middle pharyngeal constrictor, 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 bilaterally paired suprahyoid muscle located under the jaw. Its posterior belly is attached to the mastoid notch of temporal bone, and its anterior belly ...

and stylohyoid muscle have small insertions in front of these near the junction of the body with the horns. To the medial border, the thyrohyoid membrane is attached, while the anterior half of the lateral border gives insertion to the thyrohyoid muscle.

Lesser horns

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. 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 chondroglossus rises from the medial side of the base.

Development

The second

pharyngeal arch The pharyngeal arches, also known as visceral arches'','' are transient structures seen in the Animal embryonic development, embryonic development of humans and other vertebrates, that are recognisable precursors for many structures. In fish, t ...

, 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 cells named osteoblasts. It is synonymous with bone tissue formation. There are two processes resulting in t ...

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

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

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 A mammal () is a vertebrate animal of the Class (biology), class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three ...

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'') or modern humans are the most common and widespread species of primate, and the last surviving species of the genus ''Homo''. They are Hominidae, great apes characterized by their Prehistory of nakedness and clothing ...

'', 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 ( ; ''Homo neanderthalensis'' or sometimes ''H. sapiens neanderthalensis'') are an extinction, extinct group of archaic humans who inhabited Europe and Western and Central Asia during the Middle Pleistocene, Middle to Late Plei ...

man in the Kebara Cave in

Israel Israel, officially the State of Israel, is a country in West Asia. It Borders of Israel, shares borders with Lebanon to the north, Syria to the north-east, Jordan to the east, Egypt to the south-west, and the Mediterranean Sea to the west. Isr ...

led its discoverers to argue that the Neanderthals had a descended

, and thus human-like

speech Speech is the use of the human voice as a medium for language. Spoken language combines vowel and consonant sounds to form units of meaning like words, which belong to a language's lexicon. There are many different intentional speech acts, suc ...

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 process ...

, 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 ** Hyoglossus muscle ** Genioglossus ** Intrinsic muscles of the tongue **

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

***

Digastric muscle The digastric muscle (also digastricus) (named ''digastric'' as it has two 'bellies') 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 ...

*** Stylohyoid muscle *** Geniohyoid muscle ***

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

*Inferior ** Thyrohyoid muscle ** Omohyoid muscle ** Sternohyoid muscle ** Sternothyroid muscle File:Gray380.png,

Muscle Muscle is a soft tissue, one of the four basic types of animal tissue. There are three types of muscle tissue in vertebrates: skeletal muscle, cardiac muscle, and smooth muscle. Muscle tissue gives skeletal muscles the ability to muscle contra ...

s of the

and

cheek The cheeks () 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 of th ...

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 airway obstruction, obstruction of the respiratory tract#Upper respiratory tract, upper airway lea ...

(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 is a medical specialty that uses manual and instrumental techniques to diagnose or treat pathological conditions (e.g., trauma, disease, injury, malignancy), to alter bodily functions (e.g., malabsorption created by bariatric surgery s ...

that aims to potentially increase and improve the airway is called hyoid suspension. 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 or strangulation is compression of the neck that may lead to unconsciousness or death by causing an increasingly hypoxic state in the brain by restricting the flow of oxygen through the trachea. Fatal strangulation typically occurs ...

. 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 paired bony/ cartilaginous "loops" behind the throat ( pharyngeal cavity) of fish, which support the fish gills. As chordates, all vertebrate embryos develop pharyngeal arches, though the event ...

fish A fish (: fish or fishes) is an aquatic animal, aquatic, Anamniotes, anamniotic, gill-bearing vertebrate animal with swimming fish fin, fins and craniate, a hard skull, but lacking limb (anatomy), limbs with digit (anatomy), digits. Fish can ...

, which separates the first gill slit from the spiracle, and is often called the '' hyoid arch''. In many vertebrates, it also incorporates elements of other gill arches, and has a correspondingly greater number of cornua.

Amphibian Amphibians are ectothermic, anamniote, anamniotic, tetrapod, four-limbed vertebrate animals that constitute the class (biology), class Amphibia. In its broadest sense, it is a paraphyletic group encompassing all Tetrapod, tetrapods, but excl ...

s and non-avian

reptile Reptiles, as commonly defined, are a group of tetrapods with an ectothermic metabolism and Amniotic egg, amniotic development. Living traditional reptiles comprise four Order (biology), orders: Testudines, Crocodilia, Squamata, and Rhynchocepha ...

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 (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a fou ...

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'' has a pneumatized hyoid bone, one of the few cases of postcranial pneumatization of bones outside Saurischia. In woodpeckers, the hyoid bone is elongated, with the horns wrapping around the back of the skull. This is part of the system that keeps the brain cushioned and undamaged by the pecking action. In

mammals A mammal () is a vertebrate animal of the class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three middle e ...

, the hyoid often determines whether one can

roar A roar is a type of animal vocalization that is loud, deep and resonating. Many mammals have evolved to produce roars and other roar-like vocals for purposes such as long-distance communication and intimidation. These include various species of ...

. If the hyoid is incompletely

(for example: lions), it allows the animal to roar, but not purr. If the hyoid is completely ossified (for example: cheetahs), 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 (biology), family of mammals in the Order (biology), order Carnivora colloquially referred to as cats. A member of this family is also called a felid ( ). The 41 extant taxon, extant Felidae species exhibit the gre ...

). In veterinary anatomy, the term hyoid apparatus is the collective term used to refer to the