They are arranged like stacked glasses, which form an incomplete muscular circle around the pharynx. There are three circular pharyngeal constrictor muscles - superior, middle, and inferior. The muscles of the pharynx are mostly innervated by the vagus nerve - the only exception being the stylopharyngeus (glossopharyngeal nerve). All fibres insert posteriorly onto the pharyngeal raphe.Cricopharyngeal fibres originate from the cricoid cartilage.Thyropharyngeal fibres originate from the thyroid cartilage.Inferior pharyngeal constrictor – located in the laryngopharynx.Inserts posteriorly into the pharyngeal raphe.Originates from the stylohyoid ligament and the horns of the hyoid bone.Middle pharyngeal constrictor – located in the laryngopharynx.Inserts posteriorly onto the pharyngeal tubercle of the occiput and the pharyngeal raphe.Originates from the pterygomandibular ligament, alveolar process of mandible, medial pterygoid plate and pterygoid hamulus of the sphenoid bone.Superior pharyngeal constrictor – the uppermost pharyngeal constrictor.and thus propel the bolus of food inferiorly into the oesophagus. The circular muscles contract sequentially from superior to inferior to constrict the pharyngeal lumen. There are three circular pharyngeal constrictor muscles – superior, middle, and inferior. The muscles of the pharynx are mostly innervated by the vagus nerve – the only exception being the stylopharyngeus (glossopharyngeal nerve).
There are two main groups of pharyngeal muscles longitudinal and circular.
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