Palatine tonsil

Palatine tonsil structure blood supply clinical importance

2. LYMPHOID TISSUE
1.Primary – Thymus
- Bone marrow
2. Secondary - lymph nodes,
lymphoid follicles in tonsils,
Peyer's patches,
spleen,
adenoids,
skin, etc.

3. Tertiary - Distributed groups
of lymphocytes
Generate lymphocytes from
Immature progenitor cells

3. Secondary or peripheral lymphoid organs maintain mature
naive lymphocytes and initiate an adaptive immune response
Theses are the sites of lymphocyte activation by antigen
Activation leads to clonal expansion and affinity maturation
Mature Lymphocytes recirculate between the blood and the
peripheral lymphoid organs until they encounter their
specific antigen
GALT Gut associated lymphoid tissue
MALT mucosa-associated lymphatic tissue; lymphoid tissue associated
with the mucosa of the female reproductive tract, respiratory tract, etc

SALT Skin associated - dermis of the skin

4. Precursor cells in the bone marrow produce lymphocytes.
B-lymphocytes (B-cells) mature in the bone marrow.

T-lymphocytes (T-cells) mature in the thymus gland.
The ducts of the lymphatic system provide transportation
for proteins, fats, and other substances in a medium called lymph.
Lymph "Means clear water and it is basically the fluid and protein
that has been squeezed out of the blood (i.e. blood plasma).
"Unlike the cardiovascular system,
the lymphatic system is not closed and has no central pump."
"Lymph movement occurs despite low pressure due to peristalsis –
smooth muscle and skeletal activity
(everyday activity and motion of the body).

5. Nasopharynx
Oropharynx
Laryngopharynx
Oesophagus
Cricoid
Fold by Levator palatini
Salpingopharyngeal fold

6. Tensor veli palatiniLevator veli palatini

8. The palatine tonsil is an ovoid mass of lymphoid tissue
located in the oropharynx between the
anterior and posterior pillars
It has a 2 surfaces – medial and lateral and
2 poles – upper and lower

9. Medial surface
It is lined by stratified squamous non keratinising epithelium which dips into
the crypts
The crypts are 12-15 in number
Secondary crypts arise from the primary crypts and extend into the
substance of the tonsil
On of the crypts located in the upper part are larger than
the rest – crypta magna
It represents the ventral part of second pharyngeal pouch
The crypts serve to increase the surface area of the tonsil
The crypts may be filled witth cheesy material
– epithelial debris, food particles and bacteria

11. Lateral surface
It is covered by the fibrous capsule of the tonsil

The tonsillar bed is separated from the capsule by loose areolar tissue

This makes it is easy to dissect the tonsil from its bed during tonsillectomy
It is the site of collection of pus in peritonsillar abscess (quinsy)
Some fibers of palatoglossus and palatopharyngeus gets attached
to capsule of tonsil

15. Bed of tonsil
It is formed by the 2 muscles

Superior constrictor
Styloglossus

16. Tensor veli palitini
Lavator veli palitini

17. Palatopharyngeus

18. Structures related to bed of tonsil
The tonsil is separated from its bed by loose areolar tissue.

The structures forming the bed of the tonsil are:
Superior constrictor muscle
Styloglossus muscle
The structures related to the bed of the tonsil are:
styloid process (if enlarged)
glossopharyngeal nerve
facial artery
submandibular salivary gland
posterior belly of digastric
medial pterygoid muscle
angle of mandible

20. PS: Palatine / External palatine / Paratonsillar vein

21. Upper pole
It extends into the soft palate
There is a semilunar fold of mucous membrane which covers the
medial part of the upper pole
It extends from anterior pillar to posterior pillar
It encloses a potential space – supratonsillar fossa

22. Lower pole
It is attached to the tongue

A triangular fold of mucous membrane extends from the
anterior tonsillar pillar to the lower pole
It encloses a space – anterior tonsillar space

The lower pole is separated from the tongue by the tonsillo-lingual sulcus

This sulcus may harbour carcinoma

23. Blood supply
The tonsil is supplied by branches of external carotid artery
The tonsil is supplied by 5 arteries:
Tonsillar branch of facial artery (main supply)
Ascending palatine branch of facial artery
Ascending pharyngeal branch of external carotid artery
Dorsal linguae branch of lingual artery
Descending palatine branch of maxillary artery

24. Blood supply from medial surface

26. Venous drainage
Blood from the tonsil drains into the paratonsillar vein which in turn
drains into the common facial vein and pharyngeal venous plexus

27. Lymphatic drainage
Lymphatics from the tonsil pierce the superior constrictor and drain
into the upper cervical lymph nodes especially jugulodigastric (tonsillar)
lymph node
Enlarged non tender jugulodigastric lymph node is a sign of
chronic tonsillitis

28. Facial vein
Omohyoid muscle Supraclavicular nodes
Digastric muscle
Internal Jugular vein
Jugulo-omohyoid node
JUGULO-DIGASTRIC NODE

29. Nerve supply
Lesser palatine branch of sphenopalatine ganglion

Glossopharyngeal nerve

30. Nerve supply
Lesser palatine branch of sphenopalatine ganglion

Glossopharyngeal nerve

31. Waldeyer’s lymaphatic ring

32. Functions of tonsil
It has a protective function in that it prevents entry of pathogens
through the nasal and oral route
The crypts on the surface of the tonsil serve to increase the
surface area and increase the efficiency of protection against pathogens

It forms a part of Waldeyer’s lymphatic ring
Applied anatomy
Tonsils prevent infection.
Infected tonsils act as septic focus
Damage of paratonsillar vein during tonsillectomy leads to
excessive venous haemorhhage
Damage to glossopharygeal nerve leads to loss of taste sensation
Infected tonsillar pain may be referred to middle ear because of
Same nerve supply