piriform sinus

The piriform sinus is a subsite of the hypopharynx.

The persistency of the piriform sinus (especially on the left side) is a common cause of acute thyroiditis in children and adolescents.

In most cases, the infection originates in the piriform sinus and spreads to the thyroid via the fistula.

Despite all this, a persistent fistula from the piriform sinus may make the left lobe of the thyroid susceptible to infection and abscess formation.

Piriform sinus, piriform recess and piriform fossa are synonyms, referring to one of the four sites of the hypopharynx.

The tract ascends along the carotid sheath posteriorly to the internal carotid artery, under the glossopharyngeal nerve, and over the vagus nerve and hypoglossal nerve to open into the piriform sinus.