The Posterior tongue, or pharyngeal part, is the part of the tongue behind the terminal sulcus. At its root, it is directed backward, and connected with the hyoid bone by the Hyoglossi and Genioglossi muscles and the hyoglossal membrane; with the epiglottis by three folds (glossoepiglottic) of mucous membrane; with the soft palate by the glossopalatine arches; and with the pharynx by the Constrictores pharyngis superiores and the mucous membrane. It is derived primarily from the third pharyngeal arch. (The second arch has a substantial contribution during fetal development, but this later atrophies. The fourth arch may also contribute, depending upon how the boundaries of the tongue are defined.). [ http://en.wikipedia.org/wiki/Posterior_tongue ]