Piriform sinus

On either side of the laryngeal orifice in humans is a recess, termed the piriform sinus (also piriform recess, pyriform sinus, piriform fossa, or smuggler's fossa), which is bounded medially by the aryepiglottic fold, laterally by the thyroid cartilage and thyrohyoid membrane. The fossae are involved in speech. On either side of the laryngeal orifice in humans is a recess, termed the piriform sinus (also piriform recess, pyriform sinus, piriform fossa, or smuggler's fossa), which is bounded medially by the aryepiglottic fold, laterally by the thyroid cartilage and thyrohyoid membrane. The fossae are involved in speech.