25.1 Organisation of the pharynx

 


Extents:
  • 12 cm long
  • from base of skull to body of C6

Relations:

  • Anteriorly:
    • Nasal cavity
    • Nasal septum
    • Oral cavity
    • Larynx
  • Posteriorly:
    • Seperated from prevertebral fascia by retropharyngeal space containing loose areolar tissue and pharyngeal venous plexus.
  • Laterally:
    • Neurovascular bundle of the neck and styloid apparatus.
 

Pharyngeal wall

Has 5 layers:

  • Mucous membrane:
  1. Epithelium is pseudostratified columnar ciliated epithelium in the nasal part, stratified squamous non keratinised in the other parts,
  2. Subepithelial collections of lymphoid tissue.The large ones form tonsils.
  3. Lamina propria contains elastic tissue and mucous glands
  • Submucosa: Also contains elastic tissue, glands, blood vessels and nerves.
  • Pharyngobasilar fascia: Lines the internal surfaces of the pharyngeal muscles and attaches the pharynx to the base of the skull, auditory tubes and to the lateral margins of the posterior nasal apartures. Also fills the gap between the skull and superior constrictor.
  • Pharyngeal muscles: Pharyngeal constrictors, circular (intrinsic) - and longitudinal (extrinsic).
    What are the attachments?
  • Bucopharyngeal fascia:
 

Divisions:
  • Nasopharynx
  • Oropharynx
  • Laryngopharynx
 

Nasopharynx (Postnasal space)

Relations and Boundaries:

  • Roof: Body of sphenoid and basi-occiput
  • Floor: Soft palate
  • Posterior: Upper cervical vertebrae (C1, C2)
  • Anterior: Nasal cavity
  • Laterally: Eustachian tube, pharyngeal recess (fossa of Rosenmuller). Note the tubal and pharyngeal tonsils.

Blood supply: Pharyngeal branch of maxillary artery.

Innervation: Pharyngeal branch of maxillary nerve

Clinical importance: Common site of tumors (post nasal space of tumors). What are the possible effects?
enlarged pharyngeal tonsils (adenoids)
What are the possible effects?

 

Oropharynx (Pharynx proper)

Relations and Boundaries:

  • Anterior: Oral cavity palatoglossal and palatopharyngeal arches, palatine tonsils between these.
  • Superior: Soft palate.
  • Inferior: Epiglottis.
  • Posterior: C2, 3.
  • Lateral: Neurovascular bundle of neck.

Blood supply: Pharyngeal branches of external carotid and maxillary lingual artery.

Innervation: Glossopharyngeal.

Clinical importance: Tonsillitis.

 

Laryngopharynx

Relations and boundaries:

  • Anterior: Larynx, note piriform recess.
  • Posterior: c4,5,6
  • Superior: Oropharynx
  • Inferior: Esophagus
  • Lateral: Neurovascular structures of the neck

Blood supply: Ascending pharyngeal, superior thyroid arteries

Innervation: Vagus nerve

Clinical importance: Foreign bodies in the piriform recess, pharyngeal diverticulae.

 

The Oral cavity and Pharynx