In which region of the pharynx is the pyriform sinus found?

The pyriform sinus, also known as the piriform recess, is located in the hypopharynx. This anatomic structure is situated lateral to the larynx and is formed by the inner contour of the thyroid cartilage and the epiglottis. Its relevance in radiation therapy stems from its proximity to critical structures and potential involvement in conditions such as cancer.

Understanding that the hypopharynx is the lower section of the pharynx, which connects to the esophagus, highlights why the pyriform sinus is classified within this region. Its role as a passage for food and its anatomical significance in swallowing and other functions further underscore its importance in both clinical and therapeutic contexts in radiation oncology.