Middle pharyngeal constrictor
The middle pharyngeal constrictor is one of the pharyngeal constrictor muscles. The others include the superior pharyngeal constrictor and the inferior pharyngeal constrictor. The middle pharyngeal constrictor lies in between the two pharyngeal constrictors.
The origins of the middle pharyngeal constrictor are the entire length of the upper border of the greater cornu of the hyoid bone, from the lesser cornu, and the stylohyoid ligament. Its insertion is the median pharyngeal raphe. It is innervated by a branch of the vagus nerve through the pharyngeal plexus. It appears fan-like and is smaller than the inferior pharyngeal constrictor.1 And similar to other two pharyngeal constrictor muscles, it assists in the action or process of swallowing (deglutition), particularly by constricting the diameter of the pharynx when it contracts.2
1 Kulkarni, N. V. (2006). Clinical anatomy for students: problem solving approach. New Delhi: Jaypee Bros. Medical Publishers.
2 Seikel, J. A., King, D. W., & Drumright, D. G. (2010). Anatomy & physiology for speech, language, and hearing (4th ed.). Clifton Park, NY: Delmar Cengage Learning.