The pharyngeal apparatus consists of pharyngeal arches, pouches, grooves, and membranes that contribute to development of the head and neck. By the 4th week of development, 4 pairs of pharyngeal arches are present externally and are separated by pharyngeal grooves. The arches give rise to important structures of the face, neck, and organs through their mesenchymal, cartilaginous, muscular, and nervous components. Derivatives of the pharyngeal arches include bones, muscles, blood vessels, and nerves that form the jaw, tongue, larynx, and other head and neck structures.