Hyoid bone

Os hyoideum

Also known as: hyoid

A U-shaped bone in the anterior neck at the level of C3, between the mandible and the thyroid cartilage. It is the only bone that does not articulate with any other bone, being suspended by muscles and ligaments.

Show on body map Respiratory Tract

Overview

The hyoid has a quadrilateral body, paired greater horns (cornua) projecting posteriorly, and paired small lesser horns projecting upward at the junction of body and greater horns. It is suspended from the tips of the styloid processes by the stylohyoid ligaments (attached to the lesser horns) and bound to the thyroid cartilage below by the thyrohyoid membrane.

It forms an anchor for the tongue and a mobile base for the muscles of the neck: the suprahyoid muscles (digastric, stylohyoid, mylohyoid, geniohyoid) elevate it during swallowing and depress the mandible, and the infrahyoid ("strap") muscles (sternohyoid, omohyoid, thyrohyoid, sternothyroid via the larynx) depress it. The hyoglossus and middle pharyngeal constrictor also arise from it. The hyoid moves upward and forward during swallowing, helping to open the upper oesophageal sphincter and protect the airway.

Location: Anterior neck at C3 level, above the thyroid cartilage, below the mandible.

Parts & subdivisions

Body
Anterior part; attachments of geniohyoid, mylohyoid, sternohyoid, omohyoid.
Greater horns
Project backward; attachments of hyoglossus, middle constrictor, thyrohyoid; palpable lateral to the larynx.
Lesser horns
Small conical projections; attachment of the stylohyoid ligament.

Anatomy

Articulations: None with other bones — connected by the stylohyoid ligaments, thyrohyoid membrane and muscles.
Ossification: Endochondral, from six centres; greater horns ossify before birth, the body shortly after, the lesser horns at puberty. Body and greater horns fuse in middle life.
Development: Lesser horns and upper body from the 2nd pharyngeal arch (Reichert) cartilage; greater horns and lower body from the 3rd arch cartilage.

Function

Supports and anchors the tongue
Provides attachment for suprahyoid and infrahyoid muscles
Elevates the larynx during swallowing and phonation
Keeps the upper airway patent

Clinical significance

Hyoid fracture

A fractured hyoid (usually the greater horns) at autopsy strongly suggests manual strangulation, especially in older people with fused, brittle hyoids.

Thyroglossal duct cyst

The thyroid descends from the foramen caecum of the tongue past (often through) the hyoid; remnants form a midline neck cyst that moves up on swallowing and tongue protrusion. The Sistrunk operation removes the central part of the hyoid with the tract.

Compiled from standard anatomy and physiology references — see the Skeletal System sources. For education only; not medical advice.