Quick Facts
Origin: Oblique line of thyroid cartilage.
Insertion: Inferior aspects of body and greater horn of hyoid bone.
Action: Depresses hyoid bone; elevates larynx.
Innervation: Branch of anterior rami of C1 which accompanies hypoglossal nerve (CN XII).
Arterial Supply: Infrahyoid branch of superior thyroid artery.
Origin
The thyrohyoid muscle originates from the oblique line of the thyroid cartilage.
Insertion
Coursing superiorly, the thyrohyoid muscle inserts into the Inferior aspects of body and greater horn of hyoid bone.
Key Features & Anatomical Relations
Unlike the other three infrahyoid muscles, the thyrohyoid muscle is not innervated by the ansa cervicalis and receives its innervation via a communicating branch of the anterior ramus of the first cervical nerve to the hypoglossal nerve (CN XII).
Actions
The thyrohyoid muscle depresses the hyoid bone after it has been elevated. It can also elevate the larynx when the hyoid bone is fixed in position (Standring, 2016). It also fixes the hyoid bone in place with it opposes the actions of muscles that elevate the bone.
References
Standring, S. (2016) Gray's Anatomy: The Anatomical Basis of Clinical Practice. Gray's Anatomy Series 41st edn.: Elsevier Limited.
