hyoid bone | pacs

Hyoid bone.

Anterior surface. Enlarged.

An anatomical

illustration from the 1921 German edition of Anatomie des Menschen: ein Lehrbuch für Studierende und Ärzte with latin terminology.

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The hyoid is a "horseshoe-shaped" bone that serves as a structural anchor in the mid-neck. It is the only bone in the human body that does not directly articulate with another bone (other than sesamoids). It is a place of convergence of multiple small neck muscles that permit the pharyngeal phase of swallowing. The location of structures in the neck are often described in terms of relation to the hyoid (i.e. suprahyoid neck; infrahyoid neck).

Summary

location: midline structure located between the mandible and the thyroid cartilage and anterior to the epiglottis at the level of C3
- the level of the hyoid separates lymph node levels II from III in the lateral neck and levels Ia and VI in the anterior neck
articulations: none
blood supply: branches of the external carotid artery
relations: numerous muscles insert on the hyoid, detailed below

Gross anatomy

The hyoid bone is located in the mid-neck, above the thyroid cartilage, anterior to the pharynx. It is divided into three parts:

body
greater horn (one on each side, symmetric)
lesser horn (one on each side, symmetric)

Attachments

Multiple small neck muscles insert onto different parts of the hyoid :

body
- suprahyoid muscles
  - mylohyoid muscle
  - geniohyoid muscle
  - digastric muscles (indirectly)
  - stylohyoid muscle (indirectly)
- genioglossus muscle inferior fibers (indirectly)
- infrahyoid (strap) muscles
body and greater horn
- hyoglossus muscle
greater horn
- middle pharyngeal constrictor muscle

Several ligaments attach to the hyoid:

lesser horn
- stylohyoid ligament
body
- hyoepiglottic ligament
body and greater horn
- thyrohyoid membrane, including median thyrohyoid ligament

Blood supply

Branches of the external carotid artery, predominantly the infrahyoid branch of the superior thyroid artery, and branches of the lingual artery.

Relations

The position of the hyoid defines a few lymph node levels of the neck:

anteriorly: hyoid separates levels Ia (above) from VI (below)
laterally: hyoid separates level II from level III

Radiographic features

The hyoid is the ossified horseshoe-shaped structure just superior to the thyroid cartilage.

Related pathology

hyoid bone fracture
movement of the hyoid (hyoid elevation) is an indication of the strength of the pharyngeal muscles during a modified barium swallow study.