TONSILS (Palatine/ Faucial Tonsils)

Facial Artery

Tonsillar crypts are pockets or folds that occur naturally in the tonsils. The average adult tonsil has anywhere from 10 to 20 crypts. Crypts in the tonsils are usually small and debris free

The tonsils are situated one on each side of the lateral wall of oropharynx in the tonsillar fossa. The tonsillar bed is formed by pharyngobasilar fascia, palatoglossus muscle and superior constrictor muscle of the pharynx.

• Tonsillar fossa is bounded anteriorly by the palatoglossal fold and posteriorly by the palatopharyngeal fold.
• Capsule of the tonsil covers only the lateral surface of the tonsil, and is formed by pharyngobasilar fascia.
• Medial surface is covered by mucous membrane of the oral cavity, with stratified squamous epithelium.

Endoderm of the second pharyngeal pouch forms the stratified squamous, nonkeratinized epithelium lining the tonsillar crypts on pharyngeal surface of tonsil. The mesoderm forms lymphoid tissue, fibrous capsule, and connective tissue elements of tonsil.

• First pouch: eustachian tube, tympanic cavity, endodermal lining of eardrum
• Second pouch: palatine tonsils
• Third pouch: thymus and inferior parathyroid glands
• Fourth pouch: superior parathyroid, part of thymus
• Fifth pouch: parafollicular cells of thyroid

A i.e. Facial artery

The tonsils are supplied by five arteries viz.

1. Tonsillar branch of facial artery
2. Ascending pharyngeal artery from external carotid artery
3. Ascending palatine, branch of facial atery
4. Dorsal lingual branches of lingual artery
5. Descending palatine branch of maxillary artery

Ans. B Facial artery

• The arterial supply to the tonsil derives mainly from the tonsillar branch of the facial artery and the descending palatine
• artery; veins drain into the pharyngeal plexus and the lymphatic drainage from the tonsil is into the upper deep cervical lymph nodes, which may enlarge during tonsillar infection.
• The tonsil is supplied by five arteries

a. Tonsillar branch of facial– This is the main artery

b. Ascending pharyngeal artery from external carotid

c. Ascending palatine – a branch of facial artery

d. Dorsal linguae branches of lingual artery

e. Descending palatine branch of the maxillary artery.

Main source of arterial supply to tonsil is tonsilar branch of facial artery

Additional sources are ascending palatine branch of the facial artery, dorsal lingual branch of the lingual artery, ascending pharyngeal branch of the external carotid artery and greater palatine branch of the maxillary artery

Glossopharyngeal and lesser palatine nerves supply palatine tonsil

Palatine tonsil

• The Palatine tonsils are two prominent masses situated one on either side between the glossopalatine and pharyngopalatine arches.
• Each tonsil consists fundamentally of an aggregation of lymphoid tissue underlying the mucous membrane between the palatine arches.
• In the child the tonsils are relatively (and frequently absolutely) larger than in the adult
• The follicles of the tonsil are lined by a continuation of the mucous membrane of the pharynx, covered with stratified squamous epithelium

Arteries supplying the tonsil are the:

• Dorsalis linguae from the lingual
• The ascending palatine and tonsillar from the external maxillary
• The ascending pharyngeal from the external carotid
• The descending palatine branch of the internal maxillary
• A twig from the small meningeal.
• The veins end in the tonsillar plexus, on the lateral side of the tonsil
• The nerves are derived from the sphenopalatine ganglion, and from the glossopharyngeal.

Ans. is ‘a’ i.e., Tubal tonsil

Waldeyer’s ring of lymphoid tissue

• Waldeyer’s ring refers to the group of lymphatic organs that “guards” the oropharynx and nasopharynx in a roughly circular pattern, providing surveillance for pathogens or other foreign materials and mounting a defensive immunoresponse.
• The right and left palatine tonsils form the most conspicuous parts of the waldeyer’s ring. The ring is completed below by the lingual tonsils and above by pharyngeal tonsils (adenoids) and tubal tonsils.
• Since the respiratory and oral cavities may be a site of entry for many pathogens, waldeyer’s ring maintains surveillance in this critical region and is able to initiate the immune response before the pathogens invade deep into the body.
• Gerlach tonsil is a collection of lymphoid nodules near the pharyngeal opening of auditory tube. 
• It is also called as tubal tonsil.

Ans. is ‘d’ i.e., Palatoglossal fold

• Palatine tonsils are masses of lymphoid tissue that can be seen on the left and right sides at the back of the throat. 
• There are two palatine tonsils, and each palatine tonsil (right or left) lies in the tonsilar sinus (tonsilar fossa) on the lateral wall of oropharynx.
• Tonsillar fossa bounded by the palatoglossal fold in front and the palatopharyngeal fold behind. 
• Tonsils are lined by non – keratinized stratified squamous epithelium.
• Medial surface of each tonsil has 15-20 crypts, the largest of which is called Intratonsillar cleft or crypta magna (which represents persistence of the ventral portion of the second pharyngeal pouch).
• Tonsillar bed is formed from within – outwards by :-
• Li Pharyngobasilar fascia
• Superior constrictor (above) and palatopharyngeus muscle
• Styloglossus (below)
• Buccopharyngeal fascia

Ans. is ‘a’ i.e., Superior constrictor 

• Tonsillar bed is formed by the following :

1. Pharyngobasilar fascia               
2. Buccopharyngeal fascia        
3. Glossopharyngeal nerve
4. Superior constrictor muscle     
5. Styloglossus muscle