The inferior constrictor is most inferior of the three muscles which envelope the pharynx. It arises from the:
- oblique line on lamina of the thyroid cartilage
- cricothyroid arch
- anterolateral aspect of arch of cricoid cartilage
On each side the muscle passes superiorly and posteriorly to encircle the pharynx. It inserts with the fibres of the contralateral side into a median raphe posterior to the pharynx.
Often it is stated that the there are two separate parts to the inferior constrictor dependent on origin - see submenu.
The inferior pharyngeal constrictor acts to constrict the wall of the pharynx and so facilitates swallowing.
It is innervated by the pharyngeal and superior laryngeal branches of the vagus nerve (X) via the pharyngeal plexus. Motor fibres are derived from the cranial accessory nerve (XI).