What is the hyoid bone?
The hyoid bone is not literally a part of the skull the body. This is a U-shaped bone and it is situated in the front of the neck between the mandible and the larynx at the level of the third (3rd) cervical vertebra.
It is a unique bone in the sense that, it does not join with any other bone in the body, but it is eliminated from styloid processes of temporal bones by stylohyoid ligaments.
It is consists of the following five parts present in the hyoid bone:
- A body.
- A pair of greater cornu (or horns).
- A pair of lesser cornu (or horns).
The body is lengthened or elongated & quadrilateral in form. The body consists of the following two surfaces include anterior and posterior surface and two lateral ends.
- The anterior surface:
It is convex and faces forwards & upwards and the superior part is crossed by a transverse line or
ridge and in many cases or conditions, & a vertical median ridge divides the body into the following two lateral halves.
- The posterior surface:
It is a smooth and concave surface & faces backward and downwards. The posterior surface of the hyoid bone is separated or divided from the epiglottis by the thyrohyoid membrane; a bursa intervenes in the middle of the bone and the membrane.
- The lateral ends of the body on each side:
They are continuing with the greater cornu. In the early life period, the lateral ends are connected with the greater cornu by the cartilage, but after middle life, they become unified by a bone.
The greater cornu projects backward and upwards from the side of the body of the hyoid bone in the human.
They lessen in size from before backward and each cornu extremities posteriorly in a tubercle. When the neck is relaxed, the 2 greater cornua can be gripped or grasped in vivo in the middle of the index finger and the thumb, and then the hyoid bone can be moved from one side to another.
The lesser cornu is a small or little conical bony projection that is connected to the junction of the body & greater cornu. The stylohyoid ligament is connected to the tip of the lesser cornu and is sometimes ossified.