sternothyroideus

The sternothyroideus, also called the sternothyroid muscle, is one of the infrahyoid or strap muscles of the anterior neck. It lies in the deep part of the neck, inferior to the sternohyoid and anterior to the lower larynx and trachea, extending from the manubrium to the thyroid cartilage.

It arises from the posterior surface of the manubrium sterni and the adjacent part of the first costal cartilage. Its fibers ascend almost vertically to insert on the oblique line and inferior aspect of the lamina of the thyroid cartilage, just above the cricoid cartilage.

Innervation is via branches of the ansa cervicalis (C1–C3). Arterial supply typically comes from the superior thyroid artery, with contributions from the inferior thyroid artery in some individuals.

Its primary action is to depress the larynx by pulling the thyroid cartilage downward after elevation during swallowing and phonation, thereby aiding in laryngeal descent and swallowing. Variations in size and position are common.