The lymphatic drainage of pyriform fossa is to:
Pyriform sinus drains into jugular chain and then to deep cervical group of lymph nodes. Post cricoid region drains into para pharyngeal and paratracheal group of lymph nodes. Posterior pharyngeal wall drains into para pharyngeal lymph nodes and finally to deep cervical lymph nodes. Ref Tuli 1/e,p 231,232.
upper deep cervical nodes
Prelaryngeal node
Para pharyngeal nodes
Mediastinal nodes