PHARYNX

  • Length- 12cm
  • Width- 3.5cm in the upper portion and the lower portion of the pharynx is the narrowest portion of the GIT after the appendix.

Boundaries-

  • Superiorly- Base of the Skull
  • Inferiorly- Oesophagus
  • Posteriorly- Pre vertebral fascia
  • Anteriorly- Nasal cavity, Oral cavity, Larynx
  • Laterally- Medial pterygoid plate, Pterygomandibular raphe, Mandible, Tongue, Larynx, Thyroid and Cricoid cartilages, Middle ear cavity, Styloid process, CCA, ICA, ECA.

The pharynx is divided into 3 parts-

1.) Nasopharynx

  • Passage of air.
  • Located behind the nose.
  • Extends from the base of the skull to the soft palate.
  • Lines by ciliated columnar epithelium.
  • Supplied by pharyngeal branch of pterygopalatine ganglion.

2.) Oropharynx

  • Passage of food and air.
  • Extends from the soft palate to the epiglottis.
  • Lined by stratified squamous non keratinised epithelium.
  • Supplied by IX and X cranial nerves.

3.) Laryngopharynx

  • Passage of food.
  • Extends from the epiglottis to the cricoid cartilage.
  • Lined by stratified squamous non keratinised epithelium.
  • Supplied by the IX and X cranial nerves.

Muscles of the pharynx-

1.) Longitudinal Muscles

  • Stylopharyngeus
  • Palatopharyngeus – Makes the Passavant’s ridge
  • Salpingopharyngeus

2.) Circular Muscles

  • Superior constrictor
  • Middle constrictor
  • Inferior constrictor

The space between the base of the skull and the superior constrictor is called as the pharyngobasilar fascia or the SINUS OF MORGAGNI.

Killian’s dehiscence-

The inferior constrictor muscle splits into two- the stylopharyngeus and the cricopharyngeus.

The potential space between these two is called as the Killian’s dehiscence.

Incoordination in the area will lead to – ZENKERS DIVERTICULUM.

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