1 anatomy of oral cavity pharynx oesophagus
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Anatomy of Oral
Cavity, Pharynx &
OesophagusDr. Vishal Sharma
Oral Cavity
Parts of Oral Cavity
Floor of mouth
Lymphatic drainage
Intrinsic tongue muscles
Extrinsic tongue muscles
Coronal section of tongue
Actions of tongue musclesInferior Longitudinal: moves tip up & down
Superior Longitudinal: moves tip up & down
Transverse: narrows & lengthens tongue
Vertical: flattens & depresses tongue
Genioglossus: Prevents tongue from falling back
Styloglossus: Pulls tongue up & back
Palatoglossus: Pulls tongue back
Hyoglossus: Depresses tongue
Nerve Supply of Tongue
*** except palatoglossus which is supplied by
pharyngeal plexus
Anterior 2/3 Posterior 1/3
Sensory Lingual Glossopharyngeal
Motor Hypoglossal ***
Taste Chorda tympani Glossopharyngeal
Nerve
Supply
of
Tongue
Papillae in tongue
Papillae in tongue
Lingual taste buds sit on lateral borders of
raised papillae. They are classified as:
Fungiform: at tip & sides of tongue
Circumvallate: just in front of terminal sulcus
Foliate: at posterior lateral margins of tongue
Filiform: centre of tongue, have no taste buds
Papillae in tongue
Tongue Map ?
Sweet = Sucrose
Salty = NaCl
Sour = HCl
Bitter = Quinine
Umami = Glutamate
Taste Bud
Taste Pathway
Pharynx
Divisions
Divisions
Lower Limit of
Nasopharynx Lower border of soft palate or
Junction b/w hard & soft palate
Oropharynx Tip of epiglottis or
Body of hyoid bone or
Base of vallecula
Hypopharynx Lower border of cricoid or
Lower border of C6 vertebra
Anterior Relations
Nasopharynx
Nasopharyngeal isthmus
Nasopharyngeal Isthmus
Separates nasopharynx from oropharynx
Bounded anteriorly by soft palate & posteriorly
by mucosal ridge on nasopharyngeal wall called
Passavant’s ridge (due to palatopharyngeus)
Closure of this isthmus prevents nasal
regurgitation & nasal intonation
Parts of Oropharynx
Parts of Oropharynx
Oropharyngeal Isthmus
Oropharyngeal Isthmus
Separates oral cavity from oropharynx
Boundaries are:
Superior: Junction between hard & soft palate
Inferior: Circumvallate papillae
Lateral: Anterior tonsillar pillars (palatoglossus)
Waldeyer’s Tonsillar Ring
Waldeyer's tonsillar ring Vertically oriented, sub-epithelial lymphoid
tissue ring located in pharynx, thought to
function as a barrier to infection in first few
years of life. Named after nineteenth century
German anatomist Heinrich Wilhelm Gottfried
von Waldeyer-Hartz.
Parts of Hypopharynx
Coronal section of Pharynx
Layers of Pharyngeal Wall Mucosa: ciliated columnar in nasopharynx &
stratified squamous elsewhere
Pharyngo-basilar fascia
Longitudinal muscles: stylo-pharyngeus +
salpingo-pharyngeus + palato-pharyngeus
Constrictor muscles: superior + middle + inferior
Bucco-pharyngeal fascia
Muscles
Structures PassingBetween Skull Base & Superior Constrictor (Sinus of Morgagni)
Eustachian tube + Levator palatini + Tensor palatini + Ascending palatine artery
Between Superior & Middle Constrictors
Glossopharyngeal nerve & Stylopharyngeus muscle
Between Middle & Inferior Constrictors
Internal Laryngeal nerve & Superior Laryngeal artery
Below Inferior Constrictor
Recurrent Laryngeal nerve & Inferior Laryngeal artery
Nerve Supply Nasopharynx: pterygo-palatine ganglion (V2)
Oropharynx: glossopharyngeal & vagus nv
Hypopharynx: Superior & recurrent laryngeal nv
All muscles by pharyngeal nerve plexus (vagus
nv carrying cranial part of accessory nv) except
stylopharyngeus (glossopharyngeal nv) &
cricopharyngeus (also by recurrent laryngeal)
Arterial Supply Facial artery
Lingual artery
Ascending pharyngeal artery
Ascending palatine artery
Greater palatine artery
Artery of pterygoid canal
Superior laryngeal artery
Venous DrainageUpper pharynx:
Pharyngeal venous plexus situated on middle
constrictor pterygoid venous plexus &
internal jugular vein
Lower pharynx:
Inferior thyroid veins
Lymphatic Drainage Nasopharynx: upper deep cervical + retro-
pharyngeal + parapharyngeal +
posterior triangle
Oropharynx: upper deep cervical + retro-
pharyngeal + parapharyngeal
Hypopharynx: deep cervical + parapharyngeal +
paratracheal + supraclavicular
Killian’s Dehiscence
Killian’s Dehiscence Triangular weak area between thyropharyngeus
& cricopharyngeus part of inferior constrictor
Mucosa herniates through it to form hypo-
pharyngeal pouch (Zenker’s diverticulum)
Perforation occurs here during forceful
oesophagoscopy (gateway of tears)
Oesophagus
Introduction
Also called gullet
23 to 25 cm long
Extends from crico-pharyngeal sphincter (C6
vertebra) to cardiac orifice of stomach (T11
vertebra)
Anterior Curvature
Follows antero-
posterior curve of
vertebral column
through neck, thorax
(postr mediastinum)
& upper abdomen
Lateral curvatures
Starts in midline →
deviates to left at C7
→ returns to midline
at T5 → deviates to
left again at T7 to
reach gastric cardia
Natural Constrictions
Natural ConstrictionsSite Vertebral Level Distance from
central incisor
Cricopharynx C 6 15 cm
Aortic arch T 4 25 cm
Lt main bronchus
T 5 28 cm
Oesophageal hiatus
T 10 40 cm
Importance of constrictions
Common sites for lodgement of oesophageal
foreign bodies
Common sites for caustic stricture of
oesophagus
Blood SupplyPart Arterial Venous
Cervical Inferior thyroid Inferior thyroid
Thoracic Descending thoracic aorta,
Bronchial
Azygos,Hemi-azygos
Abdominal Left gastric, Inferior
phrenic
Left gastric,Abdominal azygos
Oesophageal varices
Left gastric vein is a
site of portal-systemic
anastomosis. Portal
obstruction leads to
varicose veins in
lower oesophagus
Nerve SupplyCervical: recurrent laryngeal nerve & cervical
sympathetic trunk
Thoracic: vagal trunks, oesophageal plexus & thoracic
sympathetic trunk
Abdominal: vagal trunks & thoracic sympathetic trunk
Esophageal pain mimics cardiac angina due to
common nerve supply
Lymphatic Drainage
deep cervical + posterior mediastinal + left
gastric lymph nodes
drain into coeliac lymph nodes
thoracic duct
Histology
Histology
Four coats from outside inwards:
1. Fibrous coat (adventitia)
2. Muscular coat (muscularis propria)
3. Submucous coat
4. Mucous coat
Detailed Histology
Mucous coat
1. Epithelium: non-keratinizing stratified sqamous
2. Lamina propria: loose areolar tissue with
lymphoid aggregates
3. Muscularis mucosae: produces local
movement of mucosa & helps in
drainage of gland secretions
Mucous coatPink, smooth, protective
oesophageal mucosa
leads to red, mamillated,
secretory gastric mucosa
across Z (zigzag) line at
38-40 cm from incisors.
Higher Z line seen in
Barret’s esophagus.
Z line in endoscopy
Barret’s esophagus
Submucous coat
Loose supporting areolar tissue contains:
Seromucous glands
Blood vessels
Lymphatic channels
Parasympathetic ganglia forming Meissner's
nerve plexus
Muscularis propria External longitudinal muscle
Internal circular muscle
Parasympathetic ganglia forming Auerbach's
nerve plexus lies b/w them
Upper 1/3: striated muscle
Middle 1/3: striated & smooth
Lower 1/3: smooth muscle
Fibrous coat (adventitia)
Layer of loose, supportive fibrous tissue
Conducts major vessels & nerves longitudinally
A serosa formed by visceral peritoneum
replaces adventitia of intra-abdominal segment
of oesophagus
Thank You
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