Plica triangularis is present in
The plica triangularis is a triangular vestigeal fold of mucous membrane covering the anteroinferior pa of the tonsil. The plica semilunaris, is a similar semilunar fold that may cross the upper pa of the tonsillar sinus. Ref: BD Chaurasia's HUMAN ANATOMY, Volume 3, 4th edition.
Antero-inferior pa of tonsil
Dorsum of tongue
Inlet of larynx
None
Head and neck