2. Waldeyer’s Lymphatic Ring
● The aggregations of lymphoid tissue underneath the epithelial lining
of pharyngeal wall are called tonsils
● These aggregations together constitute an interrupted circle
called Waldeyer’s ring, which forms the special feature of the interior
the pharynx.
● They surround the commencement of air and food passages.
3. Formation of Waldeyers Ring
The Waldeyer’s ring is formed by
1. Nasopharyngeal tonsil or the adenoids
2. Palatine tonsils or simply the tonsils
3. Lingual tonsil
4. Tubal tonsils (in fossa of Rosenmüller)
5. Lateral pharyngeal bands
6. Nodules (in posterior pharyngeal wall).
4.
5.
6. Nasopharyngeal Tonsil (Adenoids)
It is a subepithelial collection of lymphoid tissue at the junction of
roof and posterior wall of nasopharynx
It causes the overlying mucous membrane to be thrown into radiating
folds
It increases in size up to the age of 6 years and then gradually
atrophies.
7. Blood supply
Adenoids receive their blood supply from:
1. Ascending palatine branch of facial.
2. Ascending pharyngeal branch of external carotid.
3. Pharyngeal branch of the third part of maxillary artery.
4. Ascending cervical branch of inferior thyroid artery of
thyrocervical trunk.
8. Lymphatic drainage
Lymphatics from the adenoid drain into upper jugular nodes directly
or indirectly via retropharyngeal and parapharyngeal nodes.
Nerve supply
Nerve Supply is through CN IX and X.
They carry sensation.Referred pain to ear due to adenoiditis is also
mediated through them
9. Palatine tonsils
Palatine tonsils are two in number
Each tonsil is an ovoid mass of lymphoid tissue situated in the lateral
wall of oropharynx between the anterior and posterior pillars.
Parts of tonsil extend upwards into the soft palate, downwards into
the base of tongue and anteriorly into palatoglossal arch.
So actual size of the tonsil is bigger than the one that appears from
its surface
10. BLOOD SUPPLY
The tonsil is supplied by five arteries
1. Tonsillar branch of facial artery. This is the main artery.
2. Ascending pharyngeal artery from external carotid.
3. Ascending palatine, a branch of facial artery.
4. Dorsal linguae branches of lingual artery.
5. Descending palatine branch of maxillary artery.
VENOUS DRAINAGE
Veins from the tonsils drain into paratonsillar vein which joins the
common facial vein and pharyngeal venous plexus.
11. LYMPHATIC DRAINAGE
Lymphatics from the tonsil pierce the superior constrictor and drain
into upper deep cervical nodes particularly the jugulodigastric
(tonsillar) node situated below the angle of mandible.
NERVE SUPPLY
Lesser palatine branches of sphenopalatine ganglion (CN V)
and glossopharyngeal nerve provide sensory nerve supply.
12. Lingual tonsils
It forms the Anterior wall of Oropharynx
Situated on either side of the base of the tongue
They may show compensatory enlargement following tonsillectomy or
may be the seat of infection
13. Tubal Tonsil
It is collection of subepithelial lymphoid tissue situated at the tubal
elevation.
It is continuous with adenoid tissue and forms a part of the Waldeyer’s
ring.
When enlarged due to infection, it causes eustachian tube occlusion.
14.
15. Functions
1. Prevents the invasion of microorganisms from entering the air
and food passages
2.Helps in the defense mechanism of the respiratory and
alimentary systems.
3.Formation of Lymphocytes and Antibodies
16. Clinical significance
Tonsillitis: This inflammatory condition of the tonsils is due to viral or
bacterial infections.
It presents with Throat infection,Fever,Hoarseness or loss of voice,Issues with
swallowing
A visible white or yellow coating on the tonsils upon examination
Treatment includes painkillers, as well as antibiotics (for
immunocompromised, severe or painful cases only).
17.
18.
19. Tonsillectomy: This is a surgical procedure where the palatine tonsils are
removed from each side of the oropharynx.
The surgery is usually needed due to: Airway obstruction from enlarged
tonsils, Sleep apnoea ,Snoring , Recurrent tonsillitis
Other tonsils can also be removed in the same procedure.
As the tonsils are highly vascularized, they bleed heavily during the surgery.
Hydration and analgesics are essential for good recovery