tonsilla

Tonsilla is a term used in anatomy to refer to a mass of lymphoid tissue that is part of the immune system in the throat. The word is often used to describe the palatine tonsils, but it can also refer to other tonsillar tissues such as the pharyngeal tonsil and the lingual tonsil. Collectively, these structures form Waldeyer’s ring, a ring of lymphoid tissue that guards the entrance to the respiratory and digestive tracts.

Palatine tonsils are the most commonly referenced tonsillae. They lie on either side of the oropharynx, at the oropharyngeal isthmus, between the anterior and posterior tonsillar pillars. The pharyngeal tonsil sits high on the posterior wall of the nasopharynx, while the lingual tonsil is located at the base of the tongue. All tonsils consist of lymphoid follicles with crypts that can trap bacteria and debris.

The primary function of tonsillae is participation in mucosal immunity. They sample inhaled and ingested antigens, contributing to the development of adaptive immune responses and the production of local antibodies, such as IgA. They are particularly active in childhood and typically shrink with age.

Vascular and neural supply vary by location. The palatine tonsil receives arterial blood mainly from the tonsillar branch of the facial artery, with drainage into the pharyngeal venous plexus and then the facial or internal jugular veins. Sensory innervation is predominantly through branches of the glossopharyngeal nerve.

Clinical relevance includes tonsillitis, an inflammation that can be viral or bacterial and may lead to recurrent infections. Management ranges from conservative care to tonsillectomy, indicated for recurrent infections, obstructive symptoms, or suspected malignancy. Tonsills can also form tonsilloliths, calcifications within crypts.