Anatomy Exam 2- Pharynx 18

Pharynx is part of the

digestive and respiratory system located posterior to the nasal cavity, oral cavity, and larynx

The pharynx is roughly ___ cm

12

The pharynx extends from the

base of the skull inferiorly to the cricoid cartilage below at CV6

• at CV6 becomes continuous with the esopahgus 

Widest part of the pharynx

below the skull

Narrowest part of the pharynx

its termination at the esophagus (it is funnel shaped)

Two openings allow the pharynx to be

continuous with 7 cavities

1. Two nasal cavities

2. Two tympanic cavities

3. Oral cavity

4. Larynx

5. Esophagus

Pharynx divides into 3 parts

1. Nasopharynx- posterior to nasal cavity

2. Oropharynx- posterior to oral cavity

3. Laryngopharynx- behind the larynx 

The nasopharynx is open to the nasal cavity at the

choanae, a bony aperture located at the junction of the nasal cavity and the nasopharynx

The roof and posterior wall of the nasopharynx form a

continuous sloping surface that lies under the body of the sphenoid and basilar part of the occipital bone

Pharyngeal tonsil (nasopharynx)

mass of lymphoid tissue is embedded in the mucous membrane 

• also called adenoids, when enlarged can cause respiratory obstruction

Lateral wall of the nasopharynx is characterized by the

pharyngeal opening of the auditory tube which is 1.5 cm posterior to the inferior nasal conchae

Auditory tube (Eustachian or pharyngotympanic tube)

• 3.5 cm long

• Connects the tympanic cavity of the middle ear with the nasopharynx

• Anterior medial 2/3s: elastic cartilage (pharynx)

• Posterior lateral 1/3: bony (middle ear)

Cartilaginous part of the pharyngotympanic tube usually remains collapsed because

of its elastic issue

• opens during swallowing, yawning, and when pressure differences exist between that of the tympanic cavity and the atmospheric pressure

• when the tube opens, a small click can be heard

Torus tubarius (latin=swelling)

medial end of the cartilaginous part of the pharyngotympanic tube projects into the nasopharynx on the lateral wall just superior to the opening of the auditory tube

Three mucous membrane folds extend from the torus tubarius

• Salpingopalatine fold: torus→soft palate

• Salpinogopharyngeal fold: torus→lateral wall of pharynx

• Torus levatorius (between other 2) mouth of the tube→soft palate

Each of the folds of mucous membrane exist because of

the presence of the muscle housed by the fold

Pharyngeal Recess

portion of the nasopharynx posterior to the torus tubarius and the salpingopharyngeal fold

• lymphoid tissue is sometimes found here (tubal tonsil)

The nasopharynx communicates with the

oropharynx via the pharyngeal isthmus bounded by the soft palate anteriorly and the wall of the pharynx posteriorly

The oropharynx is continuous with the oral cavity by the

oropharyngeal isthmus with the following boundaries

• superior- soft palate

• inferior- tongue

• laterally- pillars of the fauces

Anterior pillar of the fauces (palatoglossal arch) oropharynx

a fold of the mucous membrane extending from the palate to the side of the tongue

• contains the palatoglossus muscle

Posterior pillar of the fauces (palatopharyngeal arch)

extends from the soft palate to the lateral side of the pharynx

• contains the palatopharyngeus muscle

Between the two arches is the

tonsillar bed

• this is where the palatine tonsil lies

• each palatine tonsil is a collection of lymphoid tissue under the mucous membrane of the oropharynx

Laryngopharynx (hypopharynx)

upper border of the epiglottis→cricoid cartilage

• then becomes continuous with the esophagus

lies posterior to the larnx

Either side of the larynx is a 

piriform recess

• during swallowing a bolus of food is deviated laterally by the epiglottis into one or both food channels, the piriform recesses

• the internal branch of the superior laryngeal nerve (internal) and superior laryngeal artery course under the mucous membrane in each piriform recess

Structure of the wall of the pharynx

1. Mucous membrane

2. Fibrous layer

3. Muscular layer

4. Fascial layer

Mucous membrane in the lining of the internal surface of the pharynx is continuous with the

mucous membrane lining the nasal cavity, oral cavity, and larynx and auditory tube