Corpus: Tonsillar fossa

The term tonsillar fossa refers to a paired pit in the posterior region of the oral cavity, which is formed by the two palatine arches.

The tonsillar fossa is formed by the anterior (arcus palatoglossus) and posterior palatal arches (arcus palatopharyngeus). In addition, it is bounded caudally by the triangular plica and cranially by the semilunar faucial plica. The palatine tonsil (tonsilla palatina) is located in the tonsillar bay. Both it and the tonsillar fossa itself emerge embryologically from the 2nd pharyngeal pouch.

Some authors describe a further triangular depression above the tonsillar fossa. This is the part of the tonsillar fossa that is not filled by the palatine tonsil. It is referred to as the supratonsillar fossa and cannot always be clearly separated from the tonsillar fossa.

As the palatine tonsil is fused to the tonsillar fossa, but not to the two palatine arches, it can be pushed out of the tonsillar bay a little for inspection. To do this, the base of the tongue is pressed downwards with a spatula and the patient is made to say "a" loudly. This tenses the muscles of the palatal arches and pushes the tonsil out.

In the case of an internal branchiogenic fistula (lateral cervical fistula), the inner opening of the fistula canal is located in the area of the supratonsillar fossa.

• Schulze S: mediscript short textbook embryology. 2nd edition, Elsevier Urban&Fischer-Verlag
• Schulte E. et al: PROMETHEUS LernAtlas der Anatomie: Kopf, Hals und Neuroanatomie. 4th edition, 2015, Thieme Verlag
• Norbert U: Short textbook on embryology, 2nd edition, 2005, Thieme Verlag