Superior pharyngeal constrictor

At a glance

English

Superior pharyngeal constrictor

Latin (TA2)

Constrictor superior pharyngis

System

Muscle

Region

Whole body

Side

Paired, left and right

About the superior pharyngeal constrictor

The superior constrictor forms the upper part of the muscular wall of the pharynx, behind the nasal cavity and the mouth. It is a thin, pale, four-sided sheet, weaker than the middle and inferior constrictors, and the middle constrictor overlaps its lower edge from outside. Its upper border does not reach the skull, leaving a gap that is closed by the tough pharyngobasilar fascia.

Its front attachment is a long vertical line made up of four sources, which give its four named parts. The pterygopharyngeal part comes from the lower back edge of the medial pterygoid plate, together with the pterygoid hamulus. The buccopharyngeal part comes from the pterygomandibular raphe, the seam it shares with buccinator. The mylopharyngeal part comes from the mandible just above the back end of the mylohyoid line, and the glossopharyngeal part from a few fibres at the side of the tongue. The fibres curve backwards to the pharyngeal raphe, and the uppermost reach the pharyngeal tubercle on the occipital bone's basilar part through the raphe and fascia.

In the space above the muscle, between it and the skull base, the auditory (pharyngotympanic) tube and levator veli palatini enter the pharynx. Below, in the gap between it and the middle constrictor, the stylopharyngeus muscle and the glossopharyngeal nerve slip into the pharyngeal wall. The palatine tonsil lies on its inner surface, so the muscle forms the floor of the tonsillar bed.

During swallowing it begins the wave of contraction that carries food down to the oesophagus. Its uppermost fibres also help raise a ridge on the back wall that meets the lifted soft palate, sealing the nasopharynx. It is supplied by the vagus nerve through the pharyngeal plexus, and its blood comes from the ascending pharyngeal, ascending palatine and tonsillar arteries. Because the tonsil lies directly on it, infection behind the tonsil, known as quinsy, may spread outside the muscle into the deep spaces of the neck.

Attachments, action and supply

Origin

Medial pterygoid plate and hamulus, pterygomandibular raphe, mylohyoid line of the mandible and the side of the tongue.

Insertion

Pharyngeal raphe and, through it, the pharyngeal tubercle of the occipital bone.

Action

Constricts the upper pharynx in swallowing and helps seal the nasopharynx against the soft palate.

Nerve supply

Pharyngeal plexus (vagus nerve).

Blood supply

Ascending pharyngeal artery, with the ascending palatine and tonsillar branches of the facial artery.