• 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 – ZENKER’S DIVERTICULUM.