Applied anatomy of throat

APPLIED ANATOMY OF
THROAT
DR T BALASUBRAMANIAN

Otolaryngology online

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 5. Lined by ciliated
epithelium columnar epithelium
6. Has no efferent 6. Has both afferent and
lymphatics 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 Intrinsic Lingual septum Margins of Raises tip and
longitudinal and submucous tongue sides of tongue;
fibrous layer shortens tongue

Inferior Intrinsic Body of hyoid Apex of tongue Curls tip
longitudinal and base of inferiorly;
tongue shortens tongue

Transverse Intrinsic Lingual septum Submucous Narrows and
fibrous layer lengthens
tongue

Vertical Intrinsic Superior surface Inferior surface Flattens and
of tongue of tongue broadens
tongue

Genioglossus Extrinsic Mental spine of Lateral and Depresses and
mandible inferior tongue protrudes
tongue

Hyoglossus Extrinsic Body and Lateral and Depresses and
greater horn of inferior tongue retracts tongue
hyoid

Styloglossus Extrinsic Styloid and Lateral and Retracts tongue
stylohyoid inferior tongue
ligament

Palatoglossus Extrinsic Palatine Lateral tongue Elevates
aponeurosis 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)


Applied anatomy of throat

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