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Other Terms: Os hyoideum, Os hyoïde, Hueso hyoid
This U-shaped bone has an interesting phylogenetic history. In earlier vertebrates this bone contributes to the skeletal support of the second and third gill arches. Through evolutionary time the visceral arches, from which these bones arise, become modified to contribute to the anatomy of the head and neck. This bone remains as a skeletal support for muscles associated with the tongue, larynx, and pharynx. The hyoid bone sits in the ventrosuperior neck suspended from the styloid process of the temporal bone by the stylohyoid ligament. It provides attachment to many muscles in this region. It consists of five elements - a body and bilateral lesser and greater cornua. The body is the rectangular ventral element that sits in the transverse plane. Projecting posterolaterally from the body are the paired, long, slender greater cornua. At the junction of the greater cornua and the body are smaller superior projections, the lesser cornua.
This name arises from the Greek alphabetic character upsilon. This is the letter in the Greek alphabet with a "U" shape. The ancient anatomist Herophilus named the bone because of its shape. The hyoid name comes from the aspirated sound, "hy" of this Greek alphabetic character.
The hyoid articulates with two bones: the right and left temporal bones. It forms a syndesmotic joint with the styloid processes of the two temporal bones. The ligament that joins the hyoid with the temporal bone is the stylohyoid ligament. This ligament, like the hyoid bone and the styloid processes, forms from the supportive elements of the visceral arches.
The hyoid bone ossifies from six centers. These centers first appear as cartilaginous anlage during the fifth embryonic week. The first ossification centers appear just before birth in the base of the greater cornua. Soon after birth two additional centers arise in the body. The final two centers appear during the third year in the lesser cornua. The lesser cornua originally form synovial joints with the bases of the greater cornua. Later in life these joints usually ossify.