Anatomy And Physiology

What is the Tongue Bone



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"What is the Tongue Bone"
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The tongue bone, also known as the hyoid bone or lingual bone is a fragile horsehoe-shaped bone that lies between your lower jaw (mandible) and your voice box (larynx). Image Two slender juts (called styloid processes) of the temporal bone buried deep back in both sides of your upper throat, provide the ligament supports for your hyoid bone. This allows it to bounce up and down almost like a bungee sling for your tongue as you speak.

This design of the hyoid is unique to humans and neanderthals as far as we know. In most animals, the hyoid bone is fixed up high in the throat, often by ossified ligaments limiting the movement of the tongue. However, patterns vary all over the animal kingdom, just as animals' voices vary.

Radiograph of a dog's hyoid

Domestic cats are able to purr due to an completely ossified hyoid, while lions and tigers have a more flexible hyoid, allowing roaring, but not purring (Hast 1989).

Perhaps the most unique hyoid belongs to the howler monkey. It is extra-large, completely ossified and fused to a bony larynx to form a large resonating chamber to produce its howls.

Our flexible hyoid design is a large reason why humans are capable of producing more types of sounds than most mammals. As a result, the hyoid bone has been nicknamed the "speech bone." But how does it work, exactly, in our speech?

The hyoid has 10 muscles total attached to it, as well as the liagment supports. As a result, it can move to the sides, back and forth, and up and down. In addition, it can brace against the larynx beneath, or the pharynx (upper throat cavity) around it to help hold the lower tongue and the throat shape stationary while the upper tongue produces the fine motions needed to say consonants.

Just feel your throat while you waggle the tongue; you will feel the tongue move at the top of your throat, but not at the bottom. Do not try and find your hyoid bone directly; it is fragile and well embedded in soft tissue.

Stick your tongue out, and you will feel it move up at the bottom, and perhaps you can even feel some of the muscles I will now list below:

Superior muscles (muscles located above the hyoid):

* Middle pharyngeal constrictor muscle * Hyoglossus muscle * Digastric muscle * Stylohyoid muscle * Geniohyoid muscle * Mylohyoid muscle * Genioglossus

(One mnemonic for medical students: "My Pharynx constricts making heavenly music; Diogenes must stylishly muse, genially mute. Millions mutter generallly."

Inferior muscles (below the hyoid)

* Thyrohyoid muscle, attaching to the thyroid gland * Omohyoid muscle, attaching to the shoulder bone * Sternohyoid muscle, attaching to the sternum.

HEALTH: The hyoid bone is not normally broken easily in accidents; a fractured hyoid bone is normally considered proof of strangulation, although an incompletely ossified hyoid bone is common in teenagers and must be carefully distinguished from an actual fracture. Some doctors are studying the relationship between a deeply set hyoid bone and obstructive sleep apnea, and some have even tried surgery to correct the problem.

Yes, our tongues have bones, and what amazing bones they are!

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