sternothyreoid

The term sternothyreoid refers to a small, paired muscle of the neck, though it is often considered a distinct part of the sternohyoid muscle. Anatomically, it arises from the posterior surface of the manubrium of the sternum and the adjacent clavicle, extending superiorly to insert on the oblique line of the thyroid cartilage. In some anatomical descriptions, it is considered an accessory portion of the sternohyoid or sternothyroid muscles. Its primary function is to depress the larynx and hyoid bone, playing a role in swallowing and vocalization. Together with other infrahyoid muscles, it helps to stabilize the hyoid bone and larynx. The innervation is typically provided by the ansa cervicalis. While historically described as a separate entity, its functional and anatomical integration with the sternohyoid often leads to its inclusion within that muscle group in modern anatomical texts. Variations in its presence and precise origin and insertion points have been noted in anatomical studies.