Adenoids versus tubal tonsils in the nasopharynx
The adenoids (the pharyngeal tonsil) are lymphoid tissue (immune tissue) in the roof of the nasopharynx, the part of the throat that lies behind the nose.
Remember
Think of position first: the adenoids lie in the roof of the nasopharynx, whereas the tubal tonsils lie in the side walls around the opening of the Eustachian tube (the narrow channel joining the middle ear, the area behind the eardrum, to the nasopharynx), named for the tube.
Memory aid
Each tonsil is named for its neighbour: lingual (tongue), palatine (palate arches), tubal (the tube) and pharyngeal (the pharynx roof).
Match each tonsil's name to the structure that lies beside it, so the tube points to the tubal tonsils and the pharynx roof to the pharyngeal tonsil.
The tonsils are patches of lymphoid tissue (immune tissue) found in the oropharynx and nasopharynx. The nasopharynx is the part of the throat that lies behind the nose, and the oropharynx is the part of the throat behind the mouth. There are six tonsils in all, and together they form Waldeyer's ring, a ring of lymphoid tissue around the top of the throat.
The pharyngeal tonsil is a single mass in the midline of the roof of the nasopharynx, and it is usually called the adenoids. If the adenoids swell, they can obstruct the nose, narrowing the passage behind it and causing mouth breathing and snoring.
The tubal tonsils are a pair in the lateral walls of the nasopharynx, lying around the opening of the Eustachian tube. This tube is the narrow channel that joins the middle ear to the nasopharynx.
The pharyngeal tonsil and the tubal tonsils both lie close to the tube opening, so either can affect it when enlarged. Enlarged adenoids can impair the tube's function, so the pressure in the middle ear cannot be equalised. A negative pressure (a partial vacuum) then develops behind the eardrum and fluid is drawn into the middle ear. This is glue ear, fluid behind the eardrum that is not necessarily an acute infection. Enlarged adenoids can also predispose to middle ear infection in children. Enlarged or inflamed tubal tonsils can block the opening of the tube, which is linked with recurrent middle ear infection.
To tell them apart, think of position first: roof means the pharyngeal tonsil, and the side wall beside the tube opening means the tubal tonsil.
Key facts
- Adenoids
- The pharyngeal tonsil, a single mass in the midline of the roof of the nasopharynx, usually called the adenoids.
- Tubal tonsils
- A pair around the openings of the Eustachian tubes, in the lateral walls of the nasopharynx.
- Palatine tonsils
- The pair usually called 'the tonsils', on the side walls of the oropharynx rather than the nasopharynx.
- Waldeyer's ring
- Six tonsils: one lingual (in the back third of the tongue), two palatine, two tubal and one pharyngeal.
- In children
- The adenoids are present from birth and are largest in childhood.
- Glue ear
- Fluid behind the eardrum, not necessarily an acute infection.
Exam traps
- Swelling of the palatine tonsils does not block the Eustachian tube, because they lie in the oropharynx, well below the nasopharynx; it causes a sore throat and swallowing difficulty instead.
- The adenoids are a recognised cause of Eustachian tube problems in children, yet lymphoid tissue surrounding the tube opening on the side wall is not the pharyngeal tonsil: that tonsil lies in the roof, so the tubal tonsil fits instead.
- Lying in the nasopharynx does not make a tonsil the one in the roof: the tubal tonsils are also in the nasopharynx, but they lie in the lateral walls beside the Eustachian tube openings.
Read the full notes
Tested in 6 SimpleMed+ questions
Practice it in Head and Neck, with the answer and a full explanation after every question.
Practice these questions