The hyoid moves in the midsaggital plane. Its position is expressed by vertical and horizontal coordinates representing the integrated action of the muscles connecting the hyoid to the jaw, tongue, styloid process, and infrahyoid structures. Its location is denoted by the point H, located at the apparent intersection of the anterior edge of the epiglottis with the top edge of the hyoid bone.

The point H represents the junction of curve sections such that below H the curve is a function of H only, and above it a function of H and the tongue body. The point K, an estimate of the anterior extremity of the larynx, is found to move up and down roughly synchronous with H, and is located 2.7 cm below it. As a rough estimate, anterior-posterior movement of K is found to be one half that of H. Thus the curve KH changes orientation slightly with anterior-posterior movement of the hyoid.