Pharynx and Tonsils

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Pharynx and Tonsils

I. Pharynx

• Is a funnel-shaped fibromuscular tube that extends from the base of the skull to the inferior border of the cricoid cartilage.
• Conducts food to the esophagus and air to the larynx and lungs.

II. Subdivisions of the Pharynx

A. Nasopharynx

• Is situated behind the nasal cavity above the soft palate and communicates with the nasal cavities through the nasal choanae.
• Contains the pharyngeal tonsils in its posterior wall.
• Is connected with the tympanic cavity through the auditory (eustachian) tube , which equalizes air pressure on both sides of the tympanic membrane.

B. Oropharynx

• Extends between the soft palate above and the superior border of the epiglottis below and communicates with the mouth through the oropharyngeal isthmus.
• Contains the palatine tonsils , which are lodged in the tonsillar fossae and are bounded by the palatoglossal and palatopharyngeal folds.

C. Laryngopharynx (hypopharynx)

• Extends from the upper border of the epiglottis to the lower border of the cricoid cartilage.
• Contains the piriform recesses , one on each side of the opening of the larynx, in which swallowed foreign bodies may be lodged.

III. Innervation and Blood Supply of the Pharynx

A. Pharyngeal plexus

• Lies on the middle pharyngeal constrictor.
• Is formed by the pharyngeal branches of the glossopharyngeal and vagus nerves and the sympathetic branches from the superior cervical ganglion.
• Its vagal branch innervates all of the muscles of the pharynx with the exception of the stylopharyngeus, which is supplied by the glossopharyngeal nerve.
• Its glossopharyngeal component supplies sensory fibers to the pharyngeal mucosa.

B. Arteries of the pharynx

• Are the ascending pharyngeal artery ascending palatine branch of the facial artery descending palatine arteries, pharyngeal branches of the maxillary artery, and branches of the superior and inferior thyroid arteries.

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