Hyoid Bone/ Lingual Bone / Tongue Bone/The hyoid bone (lingual bone or tongue-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 at the level of the base of the mandible in the front and the third cervical vertebra (C3) 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.
The Hyoid Bone
The hyoid, a horseshoe-shaped bone situated in the anterior of the neck, between chin and thyroid, aids tongue movement and swallowing.
Key Points
The hyoid bone is a horseshoe-shaped bone found in the neck.
It functions to protect the esophagus and facilitates a wide range of movements involved in speaking and swallowing.
The hyoid bone is only distantly articulated to other bones by muscles or ligaments.
The hyoid consists of a central part called the body, and two pairs of cornua: the greater cornu and the lesser cornu.
Ossification begins in the greater cornua toward the end of fetal life, in the hyoid body shortly afterward, and in the lesser cornua during the first or second year after birth.
Key Terms
hyoid bone: A bone in the neck that protects the esophagus and facilitates a wide range of muscle movements required for speaking and swallowing.
The hyoid bone is a horseshoe-shaped bone found in the neck. Located anteriorly between the mandible and the thyroid cartilage, the hyoid bone protects the esophagus and also facilitates the wide range of muscle activity required for speaking and swallowing. It is visible upon extension of the neck.
Position of the hyoid bone in the neck: This image shows where the hyoid bone is located.
Hyoid Bone: Anterior view of hyoid bone with sections labeled.
The hyoid bone consists of a central body and two pairs of cornua, or horns, termed greater and lesser cornua. The greater horns project backward from the body and provide a platform for key muscles and ligaments to attach to including the stylohyoid and thyrohyoid muscles.
The lesser horns are two smaller eminences that project superiorly to the join between the greater cornua and body and are attached to the body by fibrous tissue. As with the greater cornua, the lesser cornua provide a platform for muscle and ligament attachment specifically for the stylohyoid ligament.
The hyoid ossifies towards the end of fetal development, commencing in the greater cornua before completing in the body shortly after birth. The greater cornua and body are initially connected by fibrous material although this ossifies towards middle age.
Structure
The hyoid is composed of a body, two greater horns, and two lesser horns:
- Body – the central part of the bone. It has an anterior convex surface and a concave posterior surface.
- Greater horn – projects from each end of the body in a posterior, superior, and lateral direction. It acts as a site of attachment for numerous neck muscles.
- Lesser horn – arises from the superior aspect of the hyoid bone, near the origin of the greater horn. It projects superoposteriorly (toward the styloid process of the temporal bone). The stylohyoid ligament attaches to the apex of the lesser horn.
Structure
The hyoid bone is classed as an irregular bone 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 hypothyroid membrane and a quantity of loose areolar tissue; a bursa intervenes between it and the hypothyroid membrane.
- Above, the body is rounded and gives attachment to the hypothyroid 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 glandular thyroidal, when this muscle is present.
Horns
The lesser and greater horns of the hyoid
The greater and lesser horns (Latin: 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 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 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.[citation needed]
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 joints, 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.
Muscle attachments
A large number of muscles attach to the hyoid:[rx]
- Superior
- Middle pharyngeal constrictor muscle
- Hyoglossus muscle
- Genioglossus
- Intrinsic muscles of the tongue
- Suprahyoid muscles
- Digastric muscle
- Stylohyoid muscle
- Geniohyoid muscle
- Mylohyoid muscle
- Inferior
- Thyrohyoid muscle
- Omohyoid muscle
- Sternohyoid muscle
Blood supply
Blood is supplied to the hyoid bone via the lingual artery, which runs down from the tongue 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 mammals. It allows a wider range of tongue, pharyngeal and laryngeal movements by bracing these structures alongside each other in order to produce a variation.[rx] Its descent in living creatures is not unique to Homo sapiens,[rx] 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 Neanderthals was not a handicap to producing speech sounds.[rx] The discovery of a modern-looking hyoid bone of a Neanderthal man in the Kebara Cave in Israel led its discoverers to argue that the Neanderthals had a descended larynx, and thus human-like speech capabilities.[rx] However, other researchers have claimed that the morphology of the hyoid is not indicative of the larynx’s position.[rx] It is necessary to take into consideration the skull base, the mandible, and the cervical vertebrae, and a cranial reference plane.
Ligament Attachments
There are three main ligaments that attach to the hyoid bone – stylohyoid, thyrohyoid and hyoepiglottic. They act to support the position of the hyoid in the neck.
- Stylohyoid ligament – extends from the styloid process of the temporal bone to the lesser horn of the hyoid bone.
- Thyrohyoid membrane – originates from the superior border of the thyroid cartilage and attaches to the posterior surface of the hyoid bone and the greater horns.
- Hyoepiglottic ligament – connects the hyoid bone to the anterior aspect of the epiglottis.