Hyoid bone

Muhammed Asif BMLT., M.Sc- medical anatomy

Lecturer, Dept of Anatomy, YMC.

Importance ....

• In a suspected case of murder, fracture

of the hyoid bone strongly indicates

throttling and strangulation .

Importance ......

• Tip of greater cornu is palpated in the relaxed neck

near the anterior border of sternocleidomastoid

muscle, midway between the laryngeal prominence

& mastoid process.

• It forms the landmark for the ligation of lingual

artery during surgery of the neck .

Notes

• It is a u 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 3rd cervical

vertebra behind and the base of the mandible in

front.

Hyoid bone

Hyoid bone • It is kept in suspended position by muscles and

ligaments

• It provides attachment to the floor of the mouth &

to the tongue above, to the larynx below and the

epiglottis and the pharynx behind.

Hyoid bone consists of 5 parts

A body

A pair of greater cornu (or horns)

A pair of lesser cornu (or horns)

The body • It has anterior and posterior surfaces, and upper and

lower borders.

• The anterior surface is convex and is faces forwards and

upwards.

• It is crossed by transverse line in upper part &

vertical median ridge divides the body into two halves.

The body

• The posterior surface in concave and is directed

backwards and downwards.

• Each lateral end is continuous posteriorly with the greater

horn or cornua.

In early life the lateral part of the body is connected to

greater cornu by cartilage.

After middle life this connection become united by bone

The greater cornua

• Greater cornua are flattened.

• Each cornua tapers posteriorly, ends in a tubercle.

• It has two surfaces Upper and lower

• Two borders medial and lateral and a tubercle.

The lesser cornua

• These are small conical projection of bone which

project upwards from the junction of the body

and greater cornua.

• The lesser cornua are connected to the body by

fibrous tissue .

• The stylohyoid ligament is attached to the tip of

lesser cornu.

Attachments

•Suprahyoid and infrahyoid muscles

•Thyrohyoid membrane

Ossification

• Formed by Cartilagenous ossification

• Ossifies by 6 centers

• 1 primary center each for greater cornua just

before birth

• 2 secondary center for the body soon after birth

• 1 secondary center each for lesser cornua at

puberty

Development

• 2nd pharyngeal arch

• Superior part of body

• Lesser cornu

• 3rd pharyngeal arch

• Lower part of the body

• Greater cornu