Tonsillar fossa

The tonsillar fossa (or tonsillar sinus) is a space delineated by the triangular fold (plica triangularis) of the palatoglossal and palatopharyngeal arches within the lateral wall of the oral cavity.^[1]

Tonsillar fossa
The mouth cavity. (Tonsillar fossa, which is a part of the oropharynx, visible but not labeled.)
Details
Identifiers
Latin	fossa tonsillaris
TA98	A05.2.01.009
TA2	2851
FMA	55041
Anatomical terminology [edit on Wikidata]

In many cases, however, this sinus is obliterated by its walls becoming adherent to the palatine tonsils.