Bones - Hyoid Flashcards
Where is the hyoid bone located?
Base of the mandible, at the level of C3.
What is the function of the hyoid bone?
Acts as a site of attachment for neck muscles.
Structure of the hyoid?
1) Body - central part of the bone - anterior convex surface.
2) Greater horn - projects bilaterally from the body in a posterior, superior and lateral direction. Acts as a site of attachment for muscles.
3) Lesser horn - arises from superior aspect of the hyoid bone, near the origin of the greater horn. Projects superoposteriorly (towards the styloid process of the temporal bone). Acts as a site of attachment for the stylohyoid muscle.
Muscular attachments of the hyoid?
The hyoid does not attach to any bones. It is suspended in place by muscles and ligaments that attach to it.
Muscle attachments (oral cavity and pharynx)
1) Middle pharngeal constrictor
2) Hyoglossus
3) Genioglossus
Muscle attachments (suprahyoid)
1) Digastric
2) Stylohyoid
3) Geniohyoid
4) Mylohyoid
Muscle attachments (infrahyoid)
1) Thyrohyoid
2) Omohyoid
3) Sternohyoid
Ligament attachments of the hyoid?
There are three ligaments that attach to the hyoid and supports it:
1) Stylohyoid ligament - extends from the stylohyoid process of the temporal bone to the lesser horn of the hyoid bone.
2) Thyrohyoid ligament - extends from the superior border of the thyroid cartilage to the posterior surface of the hyoid and greater horns.
3) Hyoepiglottic ligament - connects hyoid bone to the anterior aspect of the epiglottis.
Clinical relevance: fracture of the hyoid bone
Relatively rare due to it being protected by the mandible and cervical spine.
However, they are characteristically associated with strangulation (found in approxiamately 1/3 of all homicides by strangulation). It is therefore a significant post-mortem finding.
It can also occur as a result of trauma, with clinical features of pain on speaking, odynophagia (pain on swallowing), and dyspnoea (difficult or laboured breathing).
