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Pharynx is a musculomembranous tube that extends from the base of skull to the level of the sixth cervical vertebra, where it is continuous with esophagus. Pharynx is subdivided into:-

  1. Nasopharynx: - Part of the pharynx above the soft palate, i.e. from the base of skull to the soft palate.
  2. Oropharynx: - Extends from the soft palate superiorly to the level of hyoid inferiorly.
  3. Hypopharynx: - The hypopharynx includes that portion of the pharynx below the level of the hyoid.


It is the part of pharynx which lies behind the nose, above the level of soft palate. It differs from the oral (oropharynx) and laryngeal part (hypopharynx) in that its cavity always remains patent. Boundaries of nasopharynx are:

  1. Roof :-Basisphenoid & basiocciput
  2. Floor:-Soft palate anteriorly; deficient posteriorly (nasopharyngeal isthmus) through which nasopharynx communicate with oropharynx.
  3. Posterior wall: - C 1 vertebra with prevertebral muscles and fascia.
  4. Anterior wall :- Choanae
  5. Lateral wall:-Pharyngeal opening of Eustachian tube is situated 1.25 cm behind the posterior end of inferior turbinate). It is bounded above and behind by an elevation called torus tubaris, behind which is a recess called fossa of Rosenmuller. Fossa of Rosenmullar corresponds to internal carotid artery.

Shape and contents of nasopharynx

  1. Nasopharynx can be divided into two sections or chambers :-
    1. Upper chamber :- Large rectangular or ovoid
    2. Lower chamber :- Tubular
  2. Contents of nasopharynx are :-
    1. Adenoids: Nasopharyngeal tonsil: Sub epithelial collection of lymphoid tissue at the junction of roof and posterior wall of nasopharynx.
    2. Nasopharyngeal Bursa: Epithelial lined median recess extending from pharyngeal mucosa to the periosteum of basiocciput. Represents attachment of notochord to pharyngeal endoderm during embryonic life. Abscess of this bursa is called as Thornwald's disease.
    3. Rathke’s pouch: Reminiscent of buccal mucosal invagination to form the anterior lobe of pituitary. Represented by a dimple above adenoids.
    4. Sinus of Morgagni: Space between base of skull and upper border of superior constrictor muscle. Through this pass auditory tube, levator palati muscIe and ascending palatine artery.


Oral part of pharynx reaches from the soft palate to the level of the hyoid bone. Major structures of the oropharynx are the palatine tonsils, soft palate and tongue base. Boundaries of oropharynx are:-

  1. Posterior wall:-Related to retropharyngeal space and lies opposite the C2& C3 vertebrae.
  2. Anterior wall: - It is deficient above, where oropharynx communicates with the oral cavity. Below anterior wallcontains :-
    1. Base of tongue
    2. Lingual tonsils
    3. Valleculae (cup shaped depression between the base of tongue and anterior surface of epiglottis)
  3. Lateral wall :- It presents :-
    1. Palatine (faucial) tonsil
    2. Anterior pillar (palatoglossal arch) formed by the palatoglossus muscle
    3. Posterior pillar (palatopharyngeal arch) formed by the palatopharyngeus muscle

Hypopharynx (Laryngopharynx)

Laryngopharynx or laryngeal part of pharynx reaches from the hyoid bone to the lower border of cricoid cartilage, when it is continuous with the esophagus. Hypopharynx lies opposite the 3rd, 4th, 5th, 6th cervical vertebrae.
Clinically, hypopharynx is subdivided into three regions:-

  1. The pyriform sinus
  2. Post-cricoid region's
  3. The posterior pharyngeal wall



Gaps between pharyngeal muscles and structure passing through them
Between the base of skull and superior constrictor, i.e. above superior constrictor (Sinus ofMorgagni):- Levator veli palatini, auditory (eustachian) tube, Ascending palatine artery.
Between middle and superior constrictors: - Stylopharyngeus muscle, Glossopharyngeal nerve.
Between middle and inferior constrictors: - Internal laryngeal nerve, superior laryngeal vessels.
Between inferior constrictor and esophagus (below inferior constrictor):- Recurrent laryngeal nerve, inferior laryngeal vessels.


Waldeyer's ring of lymphoid tissue

  1. Waldeyer's ring refers to the group of lymphatic organs that "guards" the oropharynx and nasopharynx in a roughly circular pattern, providing surveillance for pathogens or other foreign materials and mounting a defensive immunoresponse.
  2. The right and leftpalatinetonsilsform the most conspicuous parts of theWaldeyer’s ring. The ring is completed below by the lingual tonsils and above by pharyngeal tonsils(adenoids) and tubal tonsils.
  3. Since the respiratory and oral cavities may be a site of entry for many pathogens, Waldeyer’s ring maintains surveillance in this critical region and is able to initiate the immune response before the pathogens invade deep into the body.


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