Anatomy of oral cavity, pharynx and esophagus

1. Anatomy of Oral Cavity,
Pharynx and Esophagus
Dr. Krishna Koirala
2020-01-20

2. Oral Cavity

3. Anatomical regions (Oncological)
• Buccal Mucosa
– Mucosal surfaces of upper and lower lips , cheeks
– Retromolar trigone, upper and lower buccoalveolar
sulci
• Upper alveolus and gingiva
• Lower alveolus and gingiva
• Hard Palate
• Anterior 2/3 of tongue
• Floor of Mouth

5. Floor of mouth

6. Lymphatic Drainage

7. Intrinsic Tongue Muscles
• Three groups
– Transverse
– Longitudinal
(Upper and lower)
– Vertical
• Function
– Alter the shape
of tongue

8. Extrinsic tongue muscles
Alter the position of tongue
Largest muscle of tongue

9. Action of tongue muscles
• Inferior and superior longitudinal : move the tip up
and down
• Transverse : narrow and lengthen the tongue
• Vertical : flatten and depress the tongue
• Genioglossus : Prevents tongue from falling back
• Styloglossus : Pulls tongue up and back
• Palatoglossus : Pulls and raises the tongue
• Hyoglossus : Depresses the tongue

10. Nerve Supply of Tongue
Anterior 2/3 Posterior 1/3
Sensory Lingual Glossopharyngeal
Motor Genioglossus, Styloglossus and Hyoglossus
supplied by Hypoglossal
Palatoglossus supplied by spinal accessory
Taste Chorda tympani Glossopharyngeal

12. Papillae in tongue
Lingual taste buds lie on lateral borders of papillae
• Fungiform : Tip & sides of tongue
• Circumvallate : Just in front of terminal sulcus
• Foliate : Posterior lateral margins of tongue
• Filiform : Centre of tongue, have no taste buds

13. Papillae in tongue

14. Tongue Map

16. Pharynx

17. Divisions

18. Lower Limit of
Nasopharynx Lower border of soft palate or
Junction between 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

19. Anterior Relations

20. Nasopharynx

21. Nasopharyngeal Isthmus
• Separates nasopharynx from oropharynx
• Bounded anteriorly by soft palate & posteriorly by
mucosal ridge on nasopharyngeal wall ( Passavant’s
ridge) - due to palatopharyngeus)
• Closure of this isthmus prevents nasal regurgitation
and nasal intonation

22. Parts of Oropharynx

23. Oropharyngeal Isthmus
• Separates oral cavity from
oropharynx
• Boundaries
– Superior: Junction between
hard & soft palate
– Inferior: Circumvallate papillae
– Lateral: Anterior tonsillar
pillars (palatoglossus)

24. 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

25. Waldeyer’s Tonsillar Ring

26. Parts of Hypopharynx

27. Layers of pharyngeal wall
• Mucosa: ciliated columnar in nasopharynx and
stratified squamous in other areas
• Pharyngo-basilar fascia
• Longitudinal muscles : stylo-pharyngeus + salpingo-
pharyngeus + palato-pharyngeus
• Constrictor muscles: superior + middle + inferior
• Bucco-pharyngeal fascia

28. Coronal section of Pharynx

29. Muscles

30. Structures Passing
Between 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

31. Nerve Supply
• Nasopharynx : pterygo -palatine ganglion (V2)
• Oropharynx : glossopharyngeal & vagus nerve
• Hypopharynx : Superior & recurrent laryngeal nerve
• All muscles supplied by pharyngeal nerve plexus
(vagus nerve carrying cranial part of accessory nerve)
except stylopharyngeus (glossopharyngeal nerve) &
cricopharyngeus ( by recurrent laryngeal nerve)

32. Arterial Supply
• Facial artery
• Lingual artery
• Ascending pharyngeal artery
• Ascending palatine artery
• Greater palatine artery
• Artery of pterygoid canal
• Superior laryngeal artery

33. Venous Drainage
Upper pharynx
• Pharyngeal venous plexus situated on middle
constrictor  pterygoid venous plexus & internal
jugular vein
Lower pharynx
• Inferior thyroid veins

34. Lymphatic Drainage
• Nasopharynx :upper deep cervical + retro-
pharyngeal + parapharyngeal +
posterior triangle
• Oropharynx : upper deep cervical + retro-
pharyngeal + parapharyngeal
• Hypopharynx : deep cervical + parapharyngeal +
paratracheal + supraclavicular

35. Killian’s Dehiscence
• Triangular weak area between
thyropharyngeus & cricopharyngeus
part of inferior constrictor muscle
• Mucosa herniates through it to form
hypo-pharyngeal pouch (Zenker’s
diverticulum)
• Perforation occurs here during forceful
esophagoscopy (gateway of tears)

36. Oesophagus

37. • Fibromuscular tube
• 23 to 25 cm long in adults
• Extends from crico-pharyngeal sphincter (C6
vertebra) to cardiac orifice of stomach (T11 vertebra)

38. • Anteroposterior curvature
– Follows antero-posterior
curve of vertebral column
through neck, thorax
(posterior mediastinum)
and upper abdomen

39. 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

40. Natural Constrictions

41. Natural Constrictions
Site Vertebral Level Distance from
central incisor
Cricopharynx C 6 15 cm
Aortic arch T 4 23 cm
Lt main
bronchus
T 5 28 cm
Esophageal
hiatus
T 10 40 cm

42. Importance of constrictions
• Common sites
–Lodgement of esophageal foreign
bodies
–Caustic stricture of esophagus

43. Blood Supply
Part Arterial Venous
Cervical Inferior thyroid Inferior thyroid
Thoracic Descending aorta,
Bronchial
Azygos,
Hemi-azygos
Abdominal Left gastric,
Inferior phrenic
Left gastric,
Abdominal azygos

44. Nerve Supply
• Cervical : recurrent laryngeal nerve &
cervical sympathetic trunks
• Thoracic : vagal trunks, esophageal
plexus & thoracic sympathetic
trunks
• Abdominal : vagal trunks & thoracic sympathetic
trunks

45. Histology
• Four coats from inside outwards
– Mucous coat
– Submucous coat
– Muscular coat (muscularis propria)
– Fibrous coat (adventitia)

47. Mucous coat
• Epithelium
– Non-keratinizing stratified sqamous
• Lamina propria
– Loose areolar tissue with lymphoid aggregates
• Muscularis mucosae
– Produces local movement of mucosa and helps in
drainage of gland secretions

48. Pink, smooth, protective oesophageal mucosa leads
to redder, mamillated, secretory gastric mucosa
across Z line

49. Submucous coat
• Loose supporting areolar tissue contains
– Seromucous glands
– Blood vessels
– Lymphatic channels
– Parasympathetic ganglia forming Meissner's nerve
plexus

50. Muscularis propria
• Outer longitudinal muscles and
inner circular muscles
• Parasympathetic ganglia forming
Auerbach's nerve plexus b/w them
• Upper 1/3: striated muscle
• Middle 1/3: striated and smooth
• Lower 1/3: smooth muscle

51. 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