General Structure
Morphologically, the hyoid bone (os hyoideum) is an unpaired structure. Despite its small size, it plays a vital role in the biomechanics of the neck and swallowing. Anatomically, the bone is divided into three key elements:
- Body (corpus) — the central, most massive part.
- Greater horns (cornua majora) — one pair.
- Lesser horns (cornua minora) — one pair.
This architecture provides an optimal surface area for the attachment of soft tissues supporting the structures of the neck.
Anatomy of the Body
The central element of the bone is its body (corpus ossis hyoidei), which forms the anterior, thickened, and most massive portion.
Topographically, the body lies directly superior to the larynx. Projected onto the vertebral column, it corresponds to the level of the third cervical vertebra (C3). As noted, the corpus ossis hyoidei does not articulate with adjacent bones. This "suspended" state is maintained by a robust framework of muscles and ligaments, granting the bone the mobility necessary for swallowing, mastication, and speech.
Greater and Lesser Horns
Paired projections extend from the body of the bone, classified as greater and lesser horns.
- Greater horn (cornu majus): A paired structure projecting posteriorly and slightly laterally from the body. The greater horns are elongated and serve as primary attachment sites for suprahyoid, infrahyoid, and pharyngeal musculature.
- Lesser horn (cornu minus): A paired, small, cone-shaped projection located at the junction of the body and the greater horn. An important anatomical feature of the lesser horns is that the stylohyoid ligament (ligamentum stylohyoideum) attaches to them.
Anatomical Orientation
To correctly orient an isolated hyoid bone in anatomical position, remember two main landmarks:
- The anterior border of the body is convex and faces forward.
- The horns (both greater and lesser) project strictly posteriorly.
An isolated hyoid bone lacks articular surfaces, a head, a neck, or a condyle—these features are absent.