Sternohyoid muscleThe sternohyoid is a strap like infrahyoid muscle that connects the hyoid bone with the clavicle and sternum.
Along with the omohyoid muscle, it comprises the superficial plane of infrahyoid muscles, while the sternothyroid and thyrohyoid belong to the deep layer. The function of this muscle is to reestablish the breathing process by pulling the hyoid bone and larynx inferiorly after deglutition.
This article will discuss the anatomy of the sternohyoid muscle.
|Origin||Manubrium of sternum, medial end of clavicle|
|Insertion||Inferior border of body of hyoid bone|
|Action||Anterior rami of spinal nerves C1-C3 (via ansa cervicalis)|
|Innervation||Depresses hyoid bone (from elevated position)|
|Blood supply||Superior thyroid artery|
Origin and insertion
Sternohyoid muscle originates from the upper posterior aspect of manubrium of sternum and the posterior surface of the medial end of clavicle .
It extends superomedially and inserts to the inferior border of body of hyoid bone, where it adjoins the insertion of the contralateral sternohyoid muscle.
Same as other three infrahyoid muscles, the sternohyoid muscle is contained within the muscular triangle of the neck, a subdivision of the anterior triangle. The superior part of the muscle lies very close to its contralateral fellow while below the middle of their course, there is a considerable gap between them.
It lies posteriorly to the platysma and anteriorly to the larynx, the thymus (or thymic remnants) and the thyrohyoid and sternothyroid muscles. The sternohyoid (together with the sternothyroid, separates the anterior jugular vein (superficially) from the common carotid artery (deeply).
Learn more about the infrahyoid muscles here.
Vascular supply to sternohyoid comes from the superior thyroid artery (a branch of the external carotid artery), while the venous blood is conveyed by the superior thyroid vein.
The action of the sternohyoid muscle is to depress the hyoid bone after it has been elevated by the suprahyoid muscles. The elevation of the hyoid bone and thus the larynx, happens during swallowing. This action closes the airways, preventing the food from being inhaled.