Henry Gray (18251861). Anatomy of the Human Body. 1918.
membrane, and upper part of the thyroid cartilage, but is separated from these structures by a mass of fatty tissue.
The posterior or laryngeal surface is smooth, concave from side to side, concavo-convex from above downward; its lower part projects backward as an elevation, the tubercle or cushion. When the mucous membrane is removed, the surface of the cartilage is seen to be indented by a number of small pits, in which mucous glands are lodged. To its sides the aryepiglottic folds are attached.
Structure.The corniculate and cuneiform cartilages, the epiglottis, and the apices of the arytenoids at first consist of hyaline cartilage, but later elastic fibers are deposited in the matrix, converting them into yellow fibrocartilage, which shows little tendency to calcification. The thyroid, cricoid, and the greater part of the arytenoids consist of hyaline cartilage, and become more or less ossified as age advances. Ossification commences about the twenty-fifth year in the thyroid cartilage, and somewhat later in the cricoid and arytenoids; by the sixty-fifth year these cartilages may be completely converted into bone.
Ligaments.The ligaments of the larynx (Figs. 951,952) are extrinsic,i. e., those connecting the thyroid cartilage and epiglottis with the hyoid bone, and the cricoid cartilage with the trachea; and intrinsic, those which connect the several cartilages of the larynx to each other.
Extrinsic Ligaments.The ligaments connecting the thyroid cartilage with the hyoid bone are the hyothyroid membrane, and a middle and two lateral hyothyroid ligaments.
The Hyothyroid Membrane (membrana hyothyreoidea; thyrohyoid membrane) is a broad, fibro-elastic layer, attached below to the upper border of the thyroid cartilage and to the front of its superior cornu, and above to the upper margin of the posterior surface of the body and greater cornua of the hyoid bone, thus passing behind the posterior surface of the body of the hyoid, and being separated from it