Coordinates | 39°55′″N116°21′″N |
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Name | Hyoid bone |
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Latin | os hyoideum |
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Graysubject | 45 |
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Graypage | 177 |
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Caption | Hyoid bone. Anterior surface. Enlarged. |
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Image2 | Gray1194.png |
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Caption2 | Anterolateral view of head and neck. |
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Precursor | 2nd and 3rd branchial arch |
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Meshname | Hyoid+Bone |
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Meshnumber | A02.835.232.409 |
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The hyoid bone (lingual bone) (Latin os hyoideum) 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 articulated to other bones by muscles or ligaments. 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 below, and the epiglottis and pharynx behind.
Its name is derived from the Greek word hyoeides meaning "shaped like the letter upsilon" (υ).
Segments
The bone consists of a central part, called the body and two pairs of
cornua, the greater cornu and the lesser cornu.
Body of hyoid
Greater cornu (2)
Lesser cornu (2)
Embryology
The second
pharyngeal arch gives rise to the lesser cornu of hyoid and the superior part of body of hyoid. The cartilage of the third pharyngeal arch forms the greater cornu of hyoid and the lower portion of the body of hyoid.
Ossification
The hyoid is
ossified from six centers: two for the body, and one for each
cornu. Ossification commences in the greater cornua toward the end of
fetal life, in the 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.
Muscle attachments
The following muscles are attached to the hyoid:
;Superior
Middle pharyngeal constrictor muscle
Hyoglossus muscle
Digastric muscle
Stylohyoid muscle
Geniohyoid muscle
Mylohyoid muscle
;Inferior
Thyrohyoid muscle
Omohyoid muscle
Sternohyoid muscle
Function
The hyoid bone is present in many
mammals, 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, 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 2 year old babies. Moreover the larynx position of Neanderthal was not a handicap to producing speech sounds. The discovery of a modern-looking hyoid bone of a
Neanderthal man in the
Kebara Cave in
Palestine led its discoverers to argue that the Neanderthals had a descended
larynx, and thus human-like
speech capabilities. However, other researchers have claimed that the morphology of the hyoid is not indicative of the larynx's position. It is necessary to take into consideration the skull base, the mandible and the cervical vertebrae and a cranial reference plane.
Fracture and applied anatomy
Due to its position, the hyoid bone is not susceptible to easy fracture. In a suspected case of murder, a fractured hyoid strongly indicates
throttling or
strangulation. However this is not the case in children and adolescents, where the hyoid bone is still flexible as ossification is yet to be completed.
In other animals
The hyoid bone is derived from the lower half of the second
gill arch in
fish, which separates the first gill slit from the
spiracle, and is often referred to as the
hyoid arch. In many animals, it also incorporates elements of other gill arches, and has a correspondingly greater number of cornua.
Amphibians and
reptiles may have many cornua, while
mammals (including humans) have two pairs, and
birds only one. In birds, and some reptiles, the body of the hyoid is greatly extended forward, creating a solid bony support for the
tongue. The howler monkey
Alouatta has a
pneumatized hyoid bone, one of the few cases of postcranial pneumatization of bones outside
Saurischia.
Additional images
See also
Adam's apple
Bone terminology
Terms for anatomical location
References
Notes
Sources
External links
- "Anterior Triangle of the Neck: The Muscular Triangle"
()
Mnemonic:Muscles attached
Category:Irregular bones
Category:Head and neck