The pharynx is a fibromuscular tube acting as the shared pathway for food, liquids, and air. It extends from the base of the skull → upper esophagus, supporting swallowing, breathing, and speech. ✨ Its layered structure and subdivisions are clinically vital in ENT and airway management.

📍 Subdivisions of the Pharynx

👃 Nasopharynx
- Posterior to nasal cavity, above soft palate.
- Communicates with nose via choanae.
- Contains adenoids (lymphoid tissue) → part of Waldeyer’s ring.
- Clinical: Enlarged adenoids can obstruct airways, cause snoring or otitis media (via Eustachian tube blockage).
👄 Oropharynx
- From soft palate → hyoid bone.
- Contains posterior tongue, palatine tonsils, faucial pillars.
- Lined by stratified squamous epithelium (abrasion-resistant).
- Clinical: Common site of tonsillitis, peritonsillar abscess (quinsy).
🗣️ Laryngopharynx (Hypopharynx)
- Soft palate → cricoid cartilage.
- Directs food → esophagus; air → larynx.
- Lined by stratified squamous epithelium.
- Clinical: Hypopharyngeal cancers often present late due to dysphagia/hoarseness.

🧱 Wall Structure & Layers

Mucosa: Epithelium varies by region → respiratory in nasopharynx; squamous in oro-/laryngopharynx.
Muscular Layer:
- Longitudinal muscles (stylopharyngeus, palatopharyngeus, salpingopharyngeus) → elevate & widen pharynx during swallow.
- Circular constrictors (superior, middle, inferior) → propel food bolus by peristalsis.
Fascial Layers: Attach pharynx to skull base and neighbouring structures (e.g. buccopharyngeal fascia).

🩸 Blood Supply & Innervation

Arteries: External carotid branches → ascending pharyngeal, facial, lingual, maxillary.
Veins: Pharyngeal venous plexus → internal jugular vein.
Nerves:
- Pharyngeal plexus (CN IX & X) → motor + sensory.
- CN IX → sensory to oropharynx, taste posterior 1/3 tongue.
- CN X → motor to constrictors.
- CN V2 → sensory to nasopharynx.
📌 Exam tip: Gag reflex = afferent CN IX, efferent CN X.

⚙️ Functional Roles

Swallowing 🥣: Coordinated muscle action protects airway + propels bolus.
Airway protection 🛡️: Soft palate seals nasopharynx; epiglottis closes laryngeal inlet.
Speech resonance 🎶: Oropharynx acts as resonating chamber for phonation.
Immune defense 🧬: Waldeyer’s ring (adenoids, tonsils, lingual tonsil) = first-line defence.

⚠️ Clinical Significance

Obstructive sleep apnoea (OSA) → collapse of oropharyngeal walls during sleep.
Peritonsillar abscess → airway compromise, trismus.
Nasopharyngeal carcinoma → associated with EBV, often presents with cervical lymphadenopathy.
Zenker’s diverticulum (outpouching of hypopharynx) → dysphagia, regurgitation.

✅ Conclusion

The pharynx integrates respiration, swallowing, immune defence, and speech. Its subdivisions, muscular layers, and neural control make it central to ENT practice. 🔑 Key pearl: Distinguish regional epithelium + nerve supply → common OSCE and exam topic.

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Anatomy of the Pharynx

📖 Introduction