Head and neck muscles (chewing, facial, and throat muscles)
Thyrohyoid
Musculus thyrohyoideus
- Origin
- Oblique line of the thyroid cartilage
- Insertion
- Greater horn and adjacent part of the body of the hyoid bone
- Function
- Brings the thyroid cartilage closer to the hyoid bone: elevates the larynx or pulls the hyoid bone down, depending on which point is fixed; important in swallowing and raising vocal pitch
- Innervation
- C1 fibers carried by the hypoglossal nerve (CN XII), not via the ansa cervicalis
- Movement & chain
- Functions as a continuation of sternothyroid in the infrahyoid chain: with the hyoid fixed, the muscle elevates the larynx; with the thyroid cartilage fixed, it pulls the hyoid bone down.
- Palpation
- Palpable in the upper anterior neck between the thyroid cartilage and hyoid bone.
- Clinical
- An exception among the infrahyoid muscles because its innervation runs via C1 fibers along the hypoglossal nerve rather than via the ansa cervicalis, relevant when interpreting a CN XII palsy.
- Segmental innervation
- C1, via the hypoglossal nerve rather than the usual ansa cervicalis route of the other infrahyoid muscles.
- In clinical practice
- Elevates larynx toward hyoid during high-effort swallowing; innervated by C1 fibers via CN XII; targeted for laryngeal elevation in dysphagia.
- Region in the model
- Head and neck muscles (chewing, facial, and throat muscles)