ANATOMY OF TONSIL AND

OROPHARYNXT. Aruvi

III Year MBBS

SAVEETHA MEDICAL COLLEGE

OROPHARYNGEAL ANATOMY

Oropharynx - location

• The oropharynx extends from below the soft palate to the upper border of the epiglottis.

• It opens into the mouth through the oropharyngeal isthmus, demarcated by the palatoglossal arch, and faces the pharyngeal aspect of the tongue.

• Its lateral wall consists of the palatopharyngeal arch and palatine tonsil.

• Posteriorly, it is level with the bodies of the second, and upper part of the third, cervical vertebrae

Soft palate

• The soft palate is a mobile flap suspended from the posterior border of the hard palate, sloping down and back between the oral and nasal parts of the pharynx.

• The soft palate is a thick fold of mucosa enclosing an aponeurosis, muscular tissue, vessels, nerves, lymphoid tissue and mucous glands.

• A thin, fibrous, palatine aponeurosis composed of the expanded tendons of the tensor veli palatini muscles strengthens the soft palate

Palatoglossal and palatopharyngeal arches

• The lateral wall of the oropharynx presents two prominent folds, the palatoglossal and palatopharyngeal folds.

• The palatoglossal arch, the anterior fold, runs from the soft palate to the side of the tongue and contains palatoglossus.

• The palatopharyngeal arch, the posterior fold, projects more medially and passes from the soft palate to merge with the lateral wall of the pharynx; it contains palatopharyngeus.

• A triangular tonsillar fossa (tonsillar sinus), lies on each side of the oropharynx between the diverging palatopharyngeal and palatoglossal arches, and contains the palatine tonsil.

Vascular supply

• The arterial supply of the soft palate is usually derived from the ascending palatine branch of the facial artery.

• Sometimes this is replaced or supplemented by a branch of the ascending pharyngeal artery which descends forwards between the superior border of the superior constrictor and levator veli palatini, and accompanies the latter to the soft palate.

• The veins of the soft palate usually drain to the pterygoid venous plexus.

Innervation

• General sensation from most of the soft palate is carried by branches of the lesser palatine nerve and from the posterior part of the palate by pharyngeal branches from the glossopharyngeal nerve and from the plexus around the tonsil.

• The lesser palatine nerve also carries the secretomotor supply to most of the mucosa of the soft palate.

• Postganglionic sympathetic fibres run from the carotid plexus along arterial branches supplying the palate.

TONSILAR

ANATOMY

Tonsils

• Paired palatine tonsils

• Nasopharyngeal or adenoid

tonsil

• Paired tubal tonsil

• Lingual tonsil

• Together these comprise the Waldeyer’s ring

Palatine tonsil

• Palatine tonsils, occasionally called the faucial tonsils,are the tonsils on the left and right sides at the back of the throat which can often be seen as white lumps.

• The palatine tonsil is one of the mucosa-associated lymphoid tissues (MALT), located at the entrance to the upper respiratory and gastrointestinal tracts to protect the body from the entry of exogenous material through mucosal sites.

Location – Isthmus faucium

• The fauces are regarded as the two pillars, formed by the palatoglossus and the palatopharyngeus muscle and covered with mucous membrane.

• The anterior one is known as the palatoglossal arch, and the posterior one is known as the palatopharyngeal arch.

• Between these two arches is the palatine tonsil.

Isthmus Faucium

Blood supply

• Blood supply is provided by tonsillar branches of five arteries: • the dorsal lingual artery (of the lingual artery)• ascending palatine artery (of the facial artery)• tonsillar branch (of the facial artery) • ascending pharyngeal artery (of the external

carotid artery) • the lesser palatine artery (of the descending

palatine artery).

• The tonsils venous drainage is by the peritonsillar plexus, which drain into the lingual and pharyngeal veins, which in turn drain into the internal jugular vein.

Nerve supply

• The palatine tonsils receive afferent nervous innervation via the tonsillar plexus, which has contributions from the trigeminal nerve via the lesser palatine nerves, and the glossopharyngeal nerve (CN ix).

• The glossopharyngeal nerve continues past the palatine tonsil and innervates the tongue to provide general and taste sensation.

• This nerve is most likely to be damaged during a tonsillectomy, which leads to reduced or lost general sensation and taste sensation to the posterior third of the tongue.

Adenoid tonsils

• The adenoid, also known as a pharyngeal tonsil or nasopharyngeal tonsil, is situated posterior to the nasal cavity, in the roof of the nasopharynx. • Normally, in children, it

forms a soft mound in the roof and posterior wall of the nasopharynx, just above and behind the uvula.

Tubal tonsil

• The tubal tonsil is one of the four main tonsil groups comprising Waldeyer's tonsillar ring.

• The tubal tonsil is very close to the torus tubarius.

• It is located posterior to the opening of the Eustachian tube into the nasopharynx.

Lingual tonsil

• The lingual tonsils are rounded masses that cover the posterior region of the tongue.

• They are located on the dorsal surface at the base of the tongue.

• They are partially surrounded by connective tissue placing them in the group of Partially Encapsulated Lymphatic Organs, tonsils.

• They have associated mucous glands which are drained by ducts directly into the single tonsillar crypt.

Histology

• Tonsils are large non-encapsulated (or partially encapsulated) masses of lymphoid tissue.

• The luminal surface of the tonsils are covered with a stratified squamous epithelium.

• The tonsils have many invaginations which form blind crypts.

• Below the epithelium, there are many lymphoid follicles beneath which have germinal centres like the lymph nodes.