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Anatomy of Oral Cavity, Pharynx & Oesophagus

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Presentation on theme: "Anatomy of Oral Cavity, Pharynx & Oesophagus"— Presentation transcript:

1 Anatomy of Oral Cavity, Pharynx & Oesophagus
Dr. Vishal Sharma

2 Oral Cavity

3 Parts of Oral Cavity

4 Floor of mouth

5 Lymphatic drainage

6 Intrinsic tongue muscles

7 Extrinsic tongue muscles

8 Coronal section of tongue

9 Actions of tongue muscles
Inferior 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

10 Nerve Supply of Tongue Anterior 2/3 Posterior 1/3 Sensory Lingual
Glossopharyngeal Motor Hypoglossal *** Taste Chorda tympani *** except palatoglossus which is supplied by pharyngeal plexus

11 Nerve Supply of Tongue

12 Papillae in tongue

13 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

14 Papillae in tongue

15 Tongue Map ? Sweet = Sucrose Salty = NaCl Sour = HCl Bitter = Quinine
Umami = Glutamate

16 Taste Bud

17 Taste Pathway

18 Pharynx

19 Divisions

20 Divisions

21 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

22 Anterior Relations

23 Nasopharynx

24 Nasopharyngeal isthmus

25 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

26 Parts of Oropharynx

27 Parts of Oropharynx

28 Oropharyngeal Isthmus

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

30 Waldeyer’s Tonsillar Ring

31 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.

32 Parts of Hypopharynx

33 Coronal section of Pharynx

34 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

35 Muscles

36 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

37 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)

38 Arterial Supply Facial artery Lingual artery
Ascending pharyngeal artery Ascending palatine artery Greater palatine artery Artery of pterygoid canal Superior laryngeal artery

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

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

41 Killian’s Dehiscence


43 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)

44 Oesophagus

45 Introduction Also called gullet 23 to 25 cm long
Extends from crico-pharyngeal sphincter (C6 vertebra) to cardiac orifice of stomach (T11 vertebra)

46 Anterior Curvature Follows antero- posterior curve of vertebral column
through neck, thorax (postr mediastinum) & upper abdomen

47 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

48 Natural Constrictions


50 Natural Constrictions
Site 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

51 Importance of constrictions
Common sites for lodgement of oesophageal foreign bodies Common sites for caustic stricture of oesophagus

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



55 Oesophageal varices Left gastric vein is a site of portal-systemic
anastomosis. Portal obstruction leads to varicose veins in lower oesophagus

56 Nerve Supply Cervical: 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


58 Lymphatic Drainage deep cervical + posterior mediastinal + left gastric lymph nodes drain into coeliac lymph nodes thoracic duct


60 Histology

61 Histology Four coats from outside inwards: 1. Fibrous coat (adventitia) 2. Muscular coat (muscularis propria) 3. Submucous coat 4. Mucous coat

62 Detailed Histology

63 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

64 Mucous coat Pink, 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.

65 Z line in endoscopy

66 Barret’s esophagus

67 Submucous coat Loose supporting areolar tissue contains:
Seromucous glands Blood vessels Lymphatic channels Parasympathetic ganglia forming Meissner's nerve plexus

68 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


70 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

71 Thank You

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