Infrahyoid Muscles
Infrahyoid muscles lie inferior ("infra") to the hyoid bone.
Because of their actions on the larynx and hyoid bone, the infrahyoid muscles are involved in swallowing and speech.
Deep muscles:
Sternothyroid
- Originates on the manubrium of the sternum and the first costal cartilage and inserts on the oblique line of the thyroid cartilage; it depresses the larynx. It overlies the trachea.
- Originates on the oblique line of the thyroid cartilage
- Inserts on the body of the hyoid
- Depresses the hyoid and elevates the larynx
Superficial muscles:
Sternohyoid
- Originates on the manubrium and the medial end of the clavicle
- Inserts on the body of the hyoid
- Depresses the hyoid
- Originates on the superior border of the scapula and passes through a sling
- Inserts on the body of the hyoid
- Depresses, retracts, and steadies the hyoid