Hyoid bone

From Wikipedia, the free encyclopedia

Bone: Hyoid bone

Hyoid bone. Anterior surface. Enlarged.

Anterolateral view of head and neck.
Latin	os hyoideum
Gray's	subject #45 177
MeSH	A02.835.232.409

The hyoid bone ("Lingual Bone") is a bone in the human neck, not articulated to any other bone. It is supported by the muscles of the neck and in turn supports the root of the tongue. Its name is derived from the Greek word hyoeides meaning "shaped like the letter upsilon" (υ). The hyoid bone is shaped like a horseshoe, and is suspended from the tips of the styloid processes of the temporal bones by the stylohyoid ligaments.

1 Segments
2 Ossification
3 Function
4 Fracture
5 Additional images
6 See also
7 External links

[edit] Segments

It consists of five segments: a body, two greater cornua, and two lesser cornua.

[edit] The body or basihyal

The body (corpus oss. hyoidei) or central part is of a quadrilateral form. Its anterior surface 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.

The posterior surface is smooth, concave, directed backward and downward, and separated from the epiglottis by the hyothyroid membrane and a quantity of loose areolar tissue; a bursa intervenes between it and the hyothyroid membrane.

The superior border is rounded, and gives attachment to the hyothyroid membrane and some aponeurotic fibers of the genioglossus.

The inferior border 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.

In early life the lateral borders are connected to the greater cornua by synchondroses; after middle life usually by bony union.

[edit] The greater cornua or thyrohyals

The greater cornua (cornua majora) project backward from the lateral borders of the body; they are flattened from above downward and diminish in size from before backward; each ends in a tubercle to which is fixed the lateral hyothyroid ligament.

The upper surface is rough close to its lateral border, for muscular attachments: the largest of these are the origins of the hyoglossus and Constrictor pharyngis medius which extend along the whole length of the cornu; the digastric muscle and stylohyoid muscle have small insertions in front of these near the junction of the body with the cornu.

To the medial border the hyothyroid membrane is attached, while the anterior half of the lateral border gives insertion to the thyrohyoid.

[edit] The lesser cornua or ceratohyals

The lesser cornua (cornua minora) are two small, conical eminences, attached by their bases to the angles of junction between the body and greater cornua.

They are connected to the body of the bone by fibrous tissue, and occasionally to the greater cornua by distinct diarthrodial joints, which usually persist throughout life, but occasionally become ankylosed.

The lesser cornua are situated in the line of the transverse ridge on the body and appear to be morphological continuations of it.

The apex of each cornu gives attachment to the stylohyoid ligament; the Chondroglossus rises from the medial side of the base.

[edit] 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.

[edit] Function

The hyoid bone is involved in the production of human speech. It allows a wider range of tongue and laryngeal movements by bracing these structures against each other. It is not present in any of our closest living relatives, but it did exist in virtually identical form in Neanderthal man. That suggests, along with other anthropological clues of communication, that the Neanderthal employed some form of spoken language.

[edit] Fracture

Due to its position, the hyoid bone is not usually easy to fracture in most situations. Professional wrestler Lance Storm suffered such an injury in a match when Christian Cage struck his throat with a misplaced lariat (forearm strike)[1].

In cases of suspicious death, a fractured hyoid is a strong sign of strangulation.

[edit] Additional images

Larynx	Head and neck of a human embryo eighteen weeks old, with Meckel’s cartilage and hyoid bar exposed.	The ligaments of the larynx. Antero-lateral view.	Sagittal section of the larynx and upper part of the trachea.
Coronal section of larynx and upper part of trachea.	The entrance to the larynx, viewed from behind.	Sagittal section of nose mouth, pharynx, and larynx.

[edit] See also

[edit] External links

SUNY Labs 25:03-0100

This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated. Please edit the article if this is the case, and feel free to remove this notice when it is no longer relevant.

Human Bones

v • d • e