• It is a muscular tube,

deficient anteriorly,

where it lies behind

the nasal cavities, the

mouth and the larynx

• Extent: from base of

the skull to the C6

vertebra

• The wall of the

pharynx has 3 layers

1) Muscles

2) Fibrous tissue

3) Mucous

membrane

Pharynx is divided into 3 parts

1. Nasopharynx

2. Oropharynx

3. Laryngopharynx

• Lies behind the nasal cavities, above the soft palate

• Has a pure respiratory function.

• Communicates with nasal cavities.

Boundaries:

Roof: – it is formed by:

• body of sphenoid

• basilar part of occipital bone

– It shows • a collection of lymphatic tissue; pharyngeal

tonsil

Floor: – it is formed by the soft palate

– it communicates with oropharynx through the pharyngeal isthmus, which is closed during swallowing by the elevation of soft palate

Anterior wall: • formed by posterior nasal apertures

(choana)

Posterior wall: • basilar part of the occipital bone

• anterior arch of the atlas

Lateral wall:- has following features

1. Auditory tube opening: communication between nasopharynx and middle ear

2. Tubal elevation

3. Pharyngeal recess: depression behind the tubal elevation

4. Salpingopharyngeal and salpingopalatine folds

5. Collection of lymphoid tissue, tubal tonsil in submucosa of tubal elevation

• Lies behind the oral cavity

• Has a digestive & respiratory function

• Extends from the soft palate to the upper

border of epiglottis

Boundaries:

Roof: • soft palate and pharyngeal isthmus

Floor: • posterior one third of the tongue

Anterior wall: • opens into the mouth through the

oropharyngeal isthmus

Posterior wall: • supported by C2 and C3 vertibra

Lateral wall: • palatoglossal and palatopharyngeal arches

and palatine tonsil between them.

• Lies behind the larynx

• Below continuous with the esophagus

Boundaries:

• Anterior wall: larynx

• Posterior wall: C4– C6 vertebrae

• Lateral wall: shows

• Piriform fossa: Bounded

medially by the aryepiglottic fold and laterally by the thyroid cartilage and thyrohyoid membrane.

• 3 constrictors:

-superior

-inferior

-middle

• 3 longitudinal muscles:

-palatopharyngeus

-salpingopharyngeus

-stylopharygeus

Nerve supply

• Pharyngeal plexus: formed

by the branches from vagus

nerve, glossopharyngeal

nerve and superior cervical

ganglion.

• All pharyngeal muscles are

supplied by pharyngeal

plexus

• Exception –

stylopharyngeus, supplied

by glossopharyngeal nerve.

Blood supply

Arterial supply:

• Ascending pharyngeal

artery

• Tonsillar artery

• Facial

• Maxillary

• Lingual arteries

Venous drainage:

• Drain into the pharyngeal

plexus

WALDEYER’S RING OF LYMPHOID TISSUE

Pharyngeal tonsil

Tubal tonsil

Palatine tonsil

Lingual tonsil

Palatine tonsil

Tubal tonsil