applied anatomy of throat

Otolaryngology online

D R T B A L A S U B RA M A N I A N

APPLIED ANATOMY OF THROAT


WALDAYER’S RING

• Consists of two components• Outer ring – cervical nodes• Inner ring – adenoid, tonsil, posterior pharyngeal

wall lymphatics, tubal tonsil of Gerlac, lingual tonsil• Enlargement of any one of the components of

inner ring can cause oropharyngeal symptoms which include painful swallowing / difficulty in swallowing


COMPONENTS OF INNER WALDAYER’S RING


FUNCTIONS OF WALDAYER’S RING

• Antigen sampling center• Antigens from inspired air are trapped by adenoid

and tubal tonsil (inhaled antigen)• Ingested antigens are sampled by palatine tonsils• Surface area of adenoid is increased for efficient

trapping of antigen by the presence of furrows• Presence of crypts in the palatine tonsils serves to

increase its efficiency


ANATOMY OF PALATINE TONSIL

• Largest member of waldayers ring• Present in the

tonsillar fossa• Lies on either side

of oropharynx


INTRODUCTION

• Adenotonsillectomy is the commonly performed surgery• Majority of infections start from the oropharynx• Meeting point of both air & food channels• This area is well protected by the presence of

lymphoid tissue (components of waldayer’s ring)• Major antigen sampling area


TONSILLAR FOSSA

• Bounded by anterior and posterior pillars• Anterior pillar is formed by palatoglossus muscle• Posterior pillar is formed by palatopharyngeus

muscle• Triangular fold of mucous membrane extends

backwards from the palatoglossal fold to cover the inferior pole of tonsil (Plica triangularis)• Semilunar mucosal fold could be seen arising

from the upper aspect of palatopharyngeal arch extending towards the superior pole of tonsil. This separates upper pole of tonsil from uvula


TONSIL

• Outer aspect is lined by condensed pharyngobasilar fascia which forms the capsule• Medial surface of tonsil is lined by crypts• Medial surface of tonsil is lined by stratified

squamous epithelium making it an oropharyngeal component• Glossopharyngeal nerve and stylohyoid ligament

pass downwards and forwards under the superior constrictor in the lower part of tonsillar fossa


TONSIL – BLOOD SUPPLY

• Tonsillar artery a branch of facial artery is its major arterial supply. Enters the tonsil near its lower pole• Lingual artery via its dorsal lingual branches• Ascending palatine branch of facial artery• Tonsillar branch of ascending pharyngeal artery• Venous drainage is via paratonsillar vein which

drains via the pharyngeal plexus / facial vein


ADENOID

• Collection of lymphoid tissue over basisphenoid area

• It is shaped like a truncated pyramid

• Its anterior edge lies in the same plane of post nasal aperture

• Posterior edge merges with posterior pharyngeal wall

• Lined by ciliated columnar epithelium

• Surface is lined by furrows


ADENOID (CONTD)

• It enlarges during childhood (3-4 years)• As the child grows older it regresses in size• Reduction in size attributed to comparative

enlargement of nasopharynx• Its surface contains furrows, which effectively

increases its surface area by another quarter.• Grossly enlarged adenoid tissue causes “Adenoid

facies”


ADENOID FACIES

• Elongated face• Pinched nostrils• Open mouth• High arched palate• Shortened upper lip• Vacant expression


DIFFERENCES BETWEEN ADENOID AND TONSIL

Tonsil Adenoid

1. Encapsulated 1. Unencapsulated

2. Two in number 2. One

3. Has crypts 3. Has furrows

4. Present in oropharynx 4. Present in nasopharynx

5. Lined by squamous epithelium

5. Lined by ciliated columnar epithelium

6. Has no efferent lymphatics

6. Has both afferent and efferent lymphatics


PALATE

• Literally means roof of the mouth• Separates oral and nasal cavities• Hard (Bony) palate• Soft palate• Uvula


TONGUE

• Dynamic part of oral cavity• Muscle mass lined by oral mucosa• Two portions – Anterior 2/3 and posterior 1/3• Two portions separated by circumvallate papillae

and foramen caecum • Tongue base contains lymphoid tissue (Lingual

tonsil)


TONGUE (CONTD)

• Lingual papilla are projections of lamina propria covered by epithelium• 4 types of lingual papilla have been identified• Vallate, foliate, filiform and fungiform papillae.• These papillae contains taste buds• 4 extrinsic and 4 intrinsic muscles• Muscles on either side of tongue are separated by

fibrous septa


LINGUAL PAPILLAE

• Vallate – These are flat and prominent 8-12 in number. Von Ebner’s gland secrete here• Foliate papillae are present in the lateral surface

of tongue• Filiform papillae are thin and long and are present

over the entire dorsum of the anterior third of tongue• Fungiform papillae are mushroom shaped and are

present along the tip and lateral surfaces of tongue


TONGUE MUSCULATURE

Muscle Type Origin Insertion Action

Superior longitudinal

Intrinsic Lingual septum and submucous fibrous layer

Margins of tongue

Raises tip and sides of tongue; shortens tongue

Inferior longitudinal

Intrinsic Body of hyoid and base of tongue

Apex of tongue Curls tip inferiorly; shortens tongue

Transverse Intrinsic Lingual septum Submucous fibrous layer

Narrows and lengthens tongue

Vertical Intrinsic Superior surface of tongue

Inferior surface of tongue

Flattens and broadens tongue

Genioglossus Extrinsic Mental spine of mandible

Lateral and inferior tongue

Depresses and protrudes tongue

Hyoglossus Extrinsic Body and greater horn of hyoid


Depresses and retracts tongue

Styloglossus Extrinsic Styloid and stylohyoid ligament


Retracts tongue

Palatoglossus Extrinsic Palatine aponeurosis

Lateral tongue Elevates posterior tongue


TONGUE NERVE SUPPLY

• Hypoglossal nerve is the motor nerve of tongue. Innervates all lingual muscles except palatoglossus which is supplied by pharyngeal plexus

• Lingual nerve – general sensation from anterior 2/3 of tongue

• Chorda tympani branch of facial nerve – taste from anterior 2/3 of tongue

• Glossopharyngeal nerve – general and taste sensation from posterior third of tongue

• Internal laryngeal nerve – general and taste sensation from posterior third tongue and epiglottis


TONGUE (CONTD)


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applied anatomy of throat

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