Anatomy of Pharynx

The pharynx is a hollow tube that starts behind the nose, goes down the neck, and ends at the top of the trachea and esophagus. The three parts of the pharynx are the nasopharynx, oropharynx, and hypopharynx.

1. Anatomy of Pharynx

2. PHARYNX -1 Nasopharynx Dr Mathew Joseph MBBS,MD(AIIMS),BCC(Palliative Medicine) Assistant Professor Department of Anatomy Al-Azhar Medical College & Super Specialty Hospital

3. Contents Introduction Boundaries Nasopharynx – Oropharynx - Laryngopharynx Location. Communications. Pharyngeal Isthmus. Features. Applied Aspects.

4. Introduction Pharynx is a fibromuscular tube. It is a common channel for both food and air. Location- Behind the cavities of nose, mouth and the larynx. Shape - funnel shaped. Extent- From the base of the skull to the esophagus.

5. Dimensions- Length- 12-14 cm Width: At base- 3.5 cm At pharyngo-esophageal junction- 1.5 cm

6. Boundaries Superior- Base of skull [ posterior part of body of Sphenoid & Basilar part of Occipital bone in front of pharyngeal tubercle. Inferior- Continuous with esophagus at the level of lower border of cricoid cartilage anteriorly and lower border of C6 vertebra posteriorly Posterior- Prevertebral fascia. Anterior- Opens into cavities of nose, mouth and larynx. Lateral- Neurovascular bundle of neck. Styloid process with its attached muscles and ligaments

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8. Subdivisions From above downwards: Nasopharynx . Oropharynx. Laryngopharynx .

9. Nasopharynx Location- Behind choanae (posterior nasal apertures) and above soft palate. Communications- Anteriorly- with nasal cavities. Inferiorly- with oropharynx.

10. Pharyngeal Isthmus [Nasopharyngeal Isthmus] An opening bounded anteriorly by the soft palate and posteriorly by the posterior wall of pharynx ( Passavant’s ridge ).

11. Features: Nasopharyngeal (Pharyngeal) Tonsil). Orifice of Pharyngo -tympanic tube (Auditory tube or Eustachian tube). Tubal elevation. Tubal tonsil. Salpingopharyngeal fold. Salpingopalatine fold. Pharyngeal recess (Fossa of Rosenmüller ). Nasopharyngeal (Pharyngeal) Tonsil [Adenoids]- A collection of lymphoid tissue. Location- At the junction of roof and posterior wall of nasopharynx . Contains nasopharyngeal bursa. Nasopharyngeal (Pharyngeal) bursa [Pouch of Luschka ]- A mucous diverticulum which extends upwards into the substance of pharyngeal tonsil from its apex. It is developed due to adhesion of notochord to the dorsal wall of pharyngeal part of foregut.

12. Orifice of Pharyngo -tympanic tube (Auditory tube or Eustachian tube)- Location- On lateral wall of nasopharynx , approximately 1.25 cm behind inferior nasal concha . Tubal elevation- Upper and posterior margins of orifice of eustachian tube are elevated due to collection of lymphoid tissue. These elevated margins are known as tubal elevation. Tubal tonsil- Collection of lymphoid tissue in tubal elevation is known as tubal tonsil.

13. Salpingopharyngeal fold- A mucous fold which extends vertically downwards on the side wall of pharynx from tubal elevation. It contains Salpingopharyngeus muscle. Salpingopalatine fold- A mucous fold which extends downwards and forwards to the soft palate from tubal elevation. It contains Levator Palati muscle. Pharyngeal recess (Fossa of Rosenmüller ). It is a deep depression behind the tubal elevation .

14. Applied Aspects Adenoids- Enlarged nasopharyngeal tonsils due to infection. Block the posterior nares . Clinical Features- Nasal obstruction. Nasal discharge. Mouth breathing. Snoring. Protrusion of tongue. Toneless voice Small nose. Epistaxis (Nose Bleeding). Nasopharyngeal tonsils are prominent in children up to the age of 6 years. They gradually undergo atrophy at puberty. They completely disappear by the age of 20 years.

15. Adenoid Facies [Long Face Syndrome] Long, open-mouthed face of children with adenoid hypertrophy. These children are ‘ Obligatory Mouth Breathers ’. Persistent mouth breathing may be associated with development of craniofacial anomalies. The characteristic facial appearance consists of: Underdeveloped thin nostrils Short upper lip Prominent upper teeth Crowded teeth Narrow upper alveolus.  High-arched palate Hypoplastic maxilla

16. Nasopharyngeal Swab

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18. Pharynx 2 Oropharynx - Laryngopharynx Dr Mathew Joseph MBBS,MD(AIIMS),BCC(Palliative Medicine) Assistant Professor Department of Anatomy Al-Azhar Medical College & Super Specialty Hospital

19. Oropharynx

20. Introduction Extent- From lower surface of soft palate to upper border of epiglottis. Communications- Anteriorly- with Oral cavity. Above- with Nasopharynx . Inferiorly- with Laryngopharynx .

21. Oropharyngeal Isthmus It is a communicating channel between oropharynx and oral cavity. Boundaries- Above- Soft Palate Below- Dorsal surface of posterior 1/3 rd of tongue. Laterally- Palatoglossal arch. Oropharyngeal Isthmus is closed during deglutition.

22. Features Palatine tonsils. Anterior faucial pillar ( Palatoglossal arch). Posterior faucial pillar ( Palatopharyngeal arch). Lingual tonsils. Upper free end of Epiglottis. Median and lateral glossoepiglottic folds. Epiglottic valleculae.

23. Features in Lateral Wall Palatine Tonsil- Location: In the tonsillar fossa. Tonsillar fossa is located in the lateral wall of oropharynx. Tonsillar fossa is bounded anteriorly by the anterior faucial pillar ( palatoglossal arch). Tonsillar fossa is bounded posteriorly by the posterior faucial pillar ( palatopharyngeal arch). Posterior 1/3 rd of Tongue Uvula

24. Anterior faucial pillar ( Palatoglossal arch)- Runs downwards and forwards from soft palate to lateral margin of tongue (at the junction of anterior 2/3 rd and posterior 1/3 rd ). It contains Palatoglossus muscle. Posterior faucial pillar ( Palatopharyngeal arch)- Runs downwards and backwards to the pharyngeal wall. It contains Palatopharyngeus muscle.

25. Features in Anterior Wall Lingual tonsils- These are the collections of lymphoid tissue underneath the mucosa of pharyngeal part of tongue. Upper free end of Epiglottis. Median glossoepiglottic fold- A mucosal fold connecting anterior surface of epiglottis to the dorsal surface of posterior 1/3 rd of tongue. Lateral glossoepiglottic folds- Mucosal folds connecting edges of epiglottis to the dorsal surface of posterior 1/3 rd of tongue. Epiglottic valleculae- Shallow fossae between median and lateral glossoepiglottic folds.

26. Applied Aspects As oropharynx is a common channel for both food and air, sometimes food may enter into respiratory tract and cause choking .

27. Laryngopharynx [ Hypopharynx ]

28. Introduction Vertical Extent- Anteriorly- From upper border of epiglottis to lower border of lamina of cricoid cartilage. Posteriorly - From C3 vertebra to the lower border of C6 vertebra. Communications- Anteriorly- with Laryngeal cavity. Superiorly- with Oropharynx. Inferiorly- with Esophagus. Laryngopharynx communicates with laryngeal inlet through Laryngeal Inlet.

29. Features Laryngeal Inlet. Piriform fossa/recess. Laryngeal Inlet closes during deglutition. Piriform fossa [Smuggler’s Fossa]- Location- Anterior part of lateral wall, on each side of laryngeal inlet. Piriform fossa

30. Pharyngeal Wall Consists of 4 l ayers (from within outwards )- Mucous membrane. Pharyngobasilar fascia (Pharyngeal aponeurosis). Muscle layer. Buccopharyngeal fascia.

31. Mucous Membrane Epithelium- Stratified squamous except nasopharynx . Nasopharynx is lined by ciliated columnar epithelium. Epithelium tends to invaginate in sub epithelial collections of lymphoid tissue in the form of clefts (crypts). Waldeyer’s Ring- Aggregations of lymphoid tissue underneath the epithelium of pharyngeal wall in the form of an interrupted ring. Surround the commencement of air and food passages. Lymphoid collections in the Waldeyer’s ring are: Nasopharyngeal (Pharyngeal) Tonsil [Adenoids]- Posteriorly Tubal Tonsils- Postero-laterally Palatine Tonsils- Antero-laterally Lingual Tonsils- Anteriorly. These lymphoid collections prevent the invasion of microorganisms in the air and food passages.

32. Waldeyer’s Ring

33. Pharyngobasilar Fascia Fibrous thickening of submucosa . It is thick near the base of skull but thin and indistinct inferiorly. It is thickest: where it fills the gap between upper border of superior constrictor and base of skull. where it forms the pharyngeal raphe ( posteriorly ).

34. Muscle Layer 2 layers of striated muscles. Outer layer of 3 pairs of circular muscles (constrictor muscles): Superior constrictor. Middle constrictor. Inferior constrictor. Inner layer of 3 pairs of longitudinal muscles. Stylopharyngeus . Salpingopharyngeus . Palatopharyngeus .

35. Buccopharyngeal Fascia It is a layer of loose areolar tissue. It covers the outer surface of constrictor muscles. In the upper part, it is prolonged forwards to cover the Buccinator muscles. It blends with the pharyngobasilar fascia, above the upper border of superior constrictor muscles.

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