applied anatomy of throat
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D R T B A L A S U B RA M A N I A N
APPLIED ANATOMY OF THROAT
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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
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COMPONENTS OF INNER WALDAYER’S RING
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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
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ANATOMY OF PALATINE TONSIL
• Largest member of waldayers ring• Present in the
tonsillar fossa• Lies on either side
of oropharynx
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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
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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
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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
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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
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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
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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”
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ADENOID FACIES
• Elongated face• Pinched nostrils• Open mouth• High arched palate• Shortened upper lip• Vacant expression
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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
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PALATE
• Literally means roof of the mouth• Separates oral and nasal cavities• Hard (Bony) palate• Soft palate• Uvula
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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)
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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
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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
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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
Lateral and inferior tongue
Depresses and retracts tongue
Styloglossus Extrinsic Styloid and stylohyoid ligament
Lateral and inferior tongue
Retracts tongue
Palatoglossus Extrinsic Palatine aponeurosis
Lateral tongue Elevates posterior tongue
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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
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TONGUE (CONTD)
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