The hyothyroid membrane (also known as the thyrohyoid membrane) is a broad sheet of fibroelastic tissue attached below to the upper border of the thyroid cartilage and above to the upper margin of the posterior surface of the body and greater cornua of the hyoid bone.
Its middle thicker part is known as the middle thyrohyoid ligament and its posterior part is also thickened to form the lateral thyrohyoid ligament. The membrane is pierced by the superior laryngeal vessels and the internal branch of the superior laryngeal nerve.