The pharyngeal cavity: The nasopharynx, oropharynx and laryngopharynx
The pharyngeal cavity is divided according to the part it lies behind into :
1- The nasopharynx; which lies behind the nasal cavity & extends from the base of the skull to the level of the hard palate (L1).
2- The oropharynx; which lies behind the oral cavity & extends from the level of the hard palate to the glosso-epiglottic folds.
3- The laryngeal pharynx; which lies behind the laryngeal orifice.
Each one of these parts possesses special stigmata, structure, arterial & nerve supply.
• Is completely respiratory & opens anteriorly to the posterior nasal choana
• Its cross section simulates the origin of the pharyngobasilar fascia which strengthens its wall keeping it always patent
• Structures in this part are:
1- The nasopharyngeal tonsils “adenoids”: a collection of lymphatic tissue in the posterior wall of the nasopharynx near its roof.
2– The tubal tonsils: lymphatic tissue collections around the orifices of the auditory tubes.
3- The openings of Eustachian tubes: on each side, near the roof connecting it to the tympanic cavity.
4- The salpingopharyngeal fold: a mucosal fold produced by the underlying salpingopharyngeaus extending from the back of tubal orifice downward.
5– The pharyngeal recess (fossa of Rosenmuller): lies posterolateral in the wall, it contains the levator palati muscle deep to its m.m. & immediately lateral to it lies the ICA.
• Is common respiratory & digestive path. Opens anteriorly to the oral cavity constituting the back of the tongue & superiorly to the nasopharynx.
• Structures in this part are:
1- The palatoglossal fold: a mucosal fold raised by the the underlying palatoglossus separating the oral cavity from the oropharynx.
2- The palatopharyngeal fold: a mucosal fild raised by the underlying palatopharyngeus muscle.
3– The palatine tonsils:
– Two big collections of lymphoid tissue lying between the palatoglossal & palatopharyngeal folds measuring 2cm in greatest dimension
– They don’t fill the area between the two arches but leave the supratonsillar recess above them
– Their free surface is characterized by the tonsillar crypts
– Their deep surface is covered by thin but firm capsule which is continuous above with the pharyngobasilar fascia & lies deep to the superior constrictor
4- Lingual tonsils: in the posterior 1/3 of the tongue.
The Waldeyer’s tonsillar ring:
• Lies opposite to the laryngeal inlet.
• Its anterior wall is characterized by:
1- The median glosso-epiglottic fold; a midline mucosal fold between the epiglottis & the posterior 1/3 of the tongue.
2- The lateral glosso-epiglottic fold; one on either side, connecting the lateral borders of the posterior 1/3 of the tongue to the epiglottis.
3– The valleculae; on each side of the medial GEF bounded by the median GEF & lateral GEF & the posterior 1/3 of the tongue.
4- The piriform recess; is part of the larynx between the quadrate membrane medially & thyrohyoid membrane laterally.
Nerve supply of the mucosa of the pharyngeal cavity:
*Nasopharynx; pharyngeal branch of PPG (Vb)
*Oropharynx; pharyngeal branch of IX nerve
*Laryngeal pharynx; superior laryngeal branch of X nerve
*Enlarged adenoid – nasal blockage – block auditory tube – recurrent ear infections & reduced hearing.
*Pharyngeal diverticulum: herniation of food-containing mucosal pouch through the gap between the two parts of inferior constrictor seen as a swelling at the side of the neck.