The muscles connected to the hyoid move it, moving the larynx along with it. When someone swallows these muscles go into action and make the lump in the throat move.
Again, the muscles below come in pairs again. The side view diagrams do not show this. Just remember that each muscle shown here has a partner on the other side of the neck.
This muscle is the only surface muscle of todays group and by comparison much larger that the others discussed. The platysma is a sheet of muscle that starts just below the clavicle and ends at the mandible. This muscle is an expressive muscle as it assists in moving the mouth and tightens the skin when fully flexed. This can create the look of anger or assist in making the body appear active.
Action: Pulls down and widens the distance between the corners of the mouth, compresses the skin of the neck.
Hale, Robert Berverly and Coyle Terence, Anatomy Lessons From the Great Masters, Watson-Guptill publications, New York, 1977