Makindo Medical Notes Comprehensive Medical Encyclopedia | Education for Healthcare Professionals

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MEDICAL DISCLAIMER: The contents are under continuing development and improvements and despite all efforts may contain errors of omission or fact. This is not to be used for the assessment, diagnosis, or management of patients. It should not be regarded as medical advice by healthcare workers or laypeople. It is for educational purposes only. Please adhere to your local protocols. Use the BNF for drug information. If you are unwell please seek urgent healthcare advice. If you do not accept this then please do not use the website. Makindo Ltd.

Pharyngeal anatomy

🧩 Anatomy of the Pharynx

The pharynx is a muscular tube (~12–14 cm long) connecting the nasal and oral cavities to the larynx and esophagus. It acts as a common pathway for both air and food. The pharynx is divided into three main regions: the nasopharynx, oropharynx, and laryngopharynx. It plays vital roles in breathing 🌬️, swallowing 🍽️, speech 🗣️, and immune defense 🛡️.

📍 Divisions of the Pharynx

👃 Nasopharynx:
- Posterior to the nasal cavity, superior to the soft palate.
- Passageway for air only.
- Contains pharyngeal tonsils (adenoids) and openings of the Eustachian tubes ➝ pressure equalisation with the middle ear (important in otitis media in children).
👅 Oropharynx:
- Posterior to the oral cavity, extends from the soft palate to the hyoid bone.
- Pathway for both air and food.
- Contains palatine tonsils and lingual tonsils.
- Soft palate elevates during swallowing to prevent nasal regurgitation.
🎤 Laryngopharynx (Hypopharynx):
- Posterior to the larynx, extends from the hyoid bone to the esophagus.
- Food directed into esophagus; air directed into larynx.
- Epiglottis covers laryngeal inlet during swallowing ➝ protects against aspiration.

💪 Muscles of the Pharynx

The pharynx has constrictors (for propulsion) and longitudinal muscles (for elevation). They coordinate during swallowing (pharyngeal phase of deglutition).

Constrictor Muscles:
- Superior: Contracts nasopharynx ➝ prevents regurgitation into nose.
- Middle: Narrows pharynx.
- Inferior: Pushes bolus into esophagus; contains the cricopharyngeus, forming the upper esophageal sphincter.
Longitudinal Muscles:
- Stylopharyngeus: Elevates pharynx (CN IX).
- Palatopharyngeus: Elevates pharynx, narrows cavity.
- Salpingopharyngeus: Elevates pharynx, opens Eustachian tube.

🩸 Blood Supply of the Pharynx

Arterial: Ascending pharyngeal, facial, maxillary (branches of external carotid).
Venous: Pharyngeal venous plexus ➝ internal jugular vein.

🧠 Nerve Supply of the Pharynx

Motor: All pharyngeal muscles by vagus nerve (CN X), except stylopharyngeus (CN IX).
Sensory:
- Nasopharynx ➝ CN V2.
- Oropharynx ➝ CN IX (important in gag reflex afferent).
- Laryngopharynx ➝ CN X.

⚡ Functions of the Pharynx

Swallowing (Deglutition): Sequential constrictor contractions propel food ➝ esophagus.
Respiration: Conducts air ➝ larynx & trachea.
Speech: Resonating chamber for phonation.
Immune Defense: Waldeyer’s ring of tonsils traps pathogens at entry points.

💡 Clinical Pearls

❗ Killian’s dehiscence: Weak area between inferior constrictor fibers ➝ site of Zenker’s diverticulum.
👂 Recurrent otitis media in children often due to enlarged adenoids obstructing Eustachian tubes.
🤮 Gag Reflex: CN IX = afferent, CN X = efferent.
🫁 Aspiration risk increases with pharyngeal muscle weakness (e.g., post-stroke).

PLEASE NOTE LEGAL ADVICE: The contents are under continuing development and improvements and may contain errors of omission or fact. Feedback vital and always welcome at drokane at gmail.com. This is not to be used for the assessment, diagnosis or management of patients. It should not be regarded as medical advice. It is only for educational purposes. Please adhere to your local protocols. If you are unwell please seek healthcare advice from your doctor. This does not replace senior or specialist advice. If you do not accept this then please do not use the website. If you need medical advice, please consult a doctor or other appropriate medical professional. If you are a medical professional and you need advice then speak to your senior or colleagues.

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