ICL 3.5: Anatomy of the Pharynx

Question 1

what is the pharynx?

Answer 1

a musculomembranous tube, located behind the nasal cavity, oral cavity and the larynx

it extends from the base of the skull to lower border of cricoid cartilage (lower border of C6 vertebrae) where it continues with the esophagus

it is funnel-shaped, widest at the top and gradually tapers to be narrowest at the lower end

it is bony roof is formed by the sphenoid bone and basilar part of occipital bone

Question 2

what is located anterior to the pharynx?

Answer 2

nasal cavity, oral cavity and larynx

all three organs open into it, therefore, the anterior wall of the pharynx is incomplete

Question 3

what is located posterior to the pharynx?

Answer 3

it is related to prevertebral fascia covering prevertebral muscles (longus coli and longus capitis)

the retropharyngeal space separates it from the prevertebral fascia

Question 4

what is located lateral to the pharynx?

Answer 4

it’s related to all structures in the carotid triangle = carotid vessels and some of its branches, internal jugular, vagus nerve and its branches, spinal accessory, hypoglossal nerve

in fact, the superior and middle constrictor muscle form the floor of the carotid triangle.

Question 5

weird diagram

Answer 5

slide 6

Question 6

what are the 3 divisions of the pharynx?

Answer 6

1. nasopharynx –> behind the posterior nasal opening (choanae)
2. oropharynx –> behind the oral cavity
3. laryngopharynx –> behind the larynx

Question 7

where is the nasopharynx located?

Answer 7

the nasopharynx sits behind the nasal cavity which opens into it by posterior nasal openings (choanae)

it extends from the roof of the pharynx (cranial base) to the soft palate

Question 8

what structures are anatomically related to the oropharynx?

Answer 8

at the junction of the roof and posterior wall are the pharyngeal tonsil (adenoids)

on the lateral walls of the nasopharynx, there are the openings of the pharyngotympanic tubes, connecting the middle ear to the nasopharynx –> over the openings there is elevation called tubal elevation (torus tubarius)

the mucosal fold extending from the tubal elevation overlays a small muscle called salpingopharyngeus muscle

Question 9

where is the oropharynx located?

Answer 9

the oropharynx sits behind the oral cavity and extends from the soft palate to the upper border of epiglottis

it communicates with the oral cavity through oropharyngeal isthmus

Question 10

what are the anatomical features of the oropharynx?

Answer 10

1. palatoglossal fold

a mucous fold that extends from the under surface of the soft palate to the tongue and contains palatoglossus muscle

2. palatopharyngeal fold

a mucous fold that extends from the soft palate to the pharyngeal wall and contains palatopharyngeus muscle –> the palatopharyngeal fold is more prominent and form the lateral margin of the oropharyngeal isthmus

3. tonsillar fossa

the fossa between the two folds is the tonsillar fossa for palatine tonsils, and are also called anterior and posterior tonsillar pillars

Question 11

what are the palatine tonsils? where are they located?

Answer 11

they are bilateral mass of lymphoid tissue located in the lateral wall of in posterior part of the oral cavity

it sits in the tonsillar fossa between the palatoglossal and palatopharyngeal folds (the anterior and posterior tonsillar pillars)

the lateral wall of the tonsillar fossa is made by the superior constrictor muscle

Question 12

which nerve are the palatine tonsils anatomically related to?

Answer 12

glossopharyngeal nerves

so this nerve is at risk during tonsillectomy!

Question 13

what is the blood supply and venous drainage of the palatine tonsils?

Answer 13

blood supply
1. tonsillar artery = branch of facial artery

2. branches from the ascending pharyngeal, dorsals lingual artery, and greater palatine artery

venous drainage = paratonsillary vein which runs on the deep surface and joins the pharyngeal plexus of veins or the facial vein

Question 14

what is the nerve supply and lymphatic drainage of the palatine tonsils?

Answer 14

nerves: glossopharyngeal nerve mainly but also the maxillary nerve

lymphatic drainage: upper deep cervical lymph nodes

Question 15

where is the laryngopharynx located?

Answer 15

the laryngopharynx sits behind the larynx and extends from the upper margin of the epiglottis to the lower border of cricoid cartilage where it continues with the esophagus

between the two aryepiglottic folds and the side wall of the pharynx are two fossae, the piriform recesses = common site for inhaled foreign bodies to lodge*

Question 16

what is Waldeyer’s ring?

Answer 16

it’s an annulus of mucosa associated lymphoid masses sitting at the margin or the nasopharynx and oropharynx

it includes; pharyngeal tonsil, palatine tonsils, and lingual tonsils

Question 17

what are the constrictor muscles of the pharynx?

Answer 17

1. superior constrictor
2. middle constrictor
3. inferior constrictor

Question 18

what are the 3 gaps in the lateral wall of the pharynx?

Answer 18

1. upper gap
2. middle gap
3. lower gap

Question 19

where is the upper gap of the lateral wall of the pharynx?

Answer 19

it’s between the upper border of the superior constrictor and the cranial base

it admits the tensor veli palatini and levator veli palatini, pharyngotympanic tube

Question 20

where is the middle gap of the lateral wall of the pharynx?

Answer 20

it’s located between the lower border of the superior constrictor and upper border of the middle constrictor

it admits the stylopharyngeus muscle, stylohyoid ligament, and glossopharyngeal nerve

Question 21

where is the lower gap of the lateral wall of the pharynx?

Answer 21

it’s partly sealed by thyrohyoid membranes

it admits internal laryngeal nerve and superior laryngeal artery (branch of the superior thyroid)

Question 22

what are the 3 extrinsic muscles of the pharynx? what’s their action?

Answer 22

1. stylopharyngeus
2. palatopharyngeus
3. salpingopharyngeus

they elevate the pharynx and shorten it during deglutition to help propel food downward

Question 23

what is the nerve supply of the extrinsic muscles of the pharynx?

Answer 23

the stylopharyngeus is supplied by glossopharyngeal nerve (the only muscle supplied by glossopharyngeal nerve)

the palatopharyngeus and salpingopharyngeus are supplied by the motor branch of vagus to the pharyngeal and palatine plexuses

Question 24

what is the innervation of the pharynx?

Answer 24

innervation to the pharynx and soft palate is through the pharyngeal plexus of nerves located in the fascia outside the constrictor muscles

the plexus is formed by rami from:
1. vagus nerve –> motor

2. glossophyrngeal nerve –> sensory
3. superior cervical ganglion –> sympathetic

Question 25

what is the autonomic component of the innervation of the pharynx?

Answer 25

the innervation of the autonomic effectors (mucosal glands) in the pharyngeal mucosa is provided by all rami the vagus and glossopharyngeal provide parasympathetic innervation and the superior cervical ganglion provides sympathetic innervation

Question 26

what are the effects on the pharynx if the vagus nerve is injured?

Answer 26

1. dysphagia = difficulty swallowing fluids or solids 2. the wall of the pharynx on the affected side is pulled medially toward the unaffected side like a curtain = signe de Rideau 3. ipsilateral absence of pharyngeal gag reflex = touching the posterior wall of the pharynx causes reflex contraction of superior constrictor and elevation of the soft palate a bilateral lesion causes severe dysphagia

Question 27

what are the 4 layers of the pharynx?

Answer 27

1. mucous membrane (inner most) 2. fibrous layer 3. muscle layer 4. buccopharyngeal fascia (outer most)

Question 28

what is the hard palate?

Answer 28

the hard palate is a plate of bone, separating the nasal from the oral cavity the hard palate is formed by the palatine process of maxilla anteriorly and the horizontal plate of palatine bone posteriorly

Question 29

what is the soft palate?

Answer 29

the soft palate is a musculofibrous mobile flap attached to the posterior border of the hard palate sloping backward and downward it separates nasopharynx from oropharynx . it tapers gradually to form a tongue like process called the uvula movements of the soft palate essential for deglutition, blowing, speech, cough and sneezing

Question 30

what are the 4 extrinsic palatine muscles?

Answer 30

1. tensor veli palatini 2. levator veli palatini 3. palatoglossus 4. palatopharyngeus

Question 31

what is the tensor veli palatini?

Answer 31

an extrinsic palatine muscle that tenses the soft palate so it's used to open the pharyngotympanic tube during swallowing and yawing

Question 32

what is the levator veli palatini?

Answer 32

an extrinsic palatine muscle that elevates the soft palate

Question 33

what is the palatoglossus?

Answer 33

an extrinsic palatine muscle --> it's a small muscle with the mucosa covering it forms the palatoglossal fold contraction of the muscle depresses the soft palate, and approximates the two palatoglossal arch together during deglutition

Question 34

what is the palatopharyngeus?

Answer 34

an extrinsic palatine muscle that pulls the pharynx upward and forward, shortening it and help propel food down the pharyngeal cavity --> when they contract they approximate the palatopharyngeal arches together and narrow the oropharyngeal isthmus it's a small muscle with it’s overlying mucosa form the palatopharyngeal fold. The two palatopharyngeal folds form the lateral wall of oropharyngeal isthmus

Question 35

what are the intrinsic palatine muscles?

Answer 35

there's only one intrinsic muscle! the muscles uvulae it arises from the posterior nasal spine of the palatine bone and is enclosed between the two laminae of the palatine aponeurosis --> It inserts beneath the mucosa of the uvula it elevates and retracts the uvula, closing the nasopharynx during deglutition

Question 36

what is the palatine aponeurosis?

Answer 36

a thin fibrous sheet that strengthen and support the soft palate it attaches to the posterior border and inferior surface of the hard palate it is composed mainly by the expanded tendon of the tensor veli palatini muscle it is formed of two laminae that enclose the musculus uvula all other palatine muscles arise or insert into to the palatine aponeurosis!

Question 37

what is the innervation of the palatine muscles?

Answer 37

all the muscles of the palate are supplied by the pharyngeal branch of vagus through pharyngeal plexus exception: tensor veli palatini is supplied by a branch of mandibular nerve

Question 38

what happens to the pharynx when the pharyngeal branch of the vagus is injured?

Answer 38

1. the arch of the soft palate is lowered on the affected side 2. on phonation, the soft palate fails to elevate, resulting in nasal voice 3. the uvula deviates to the unaffected side 4. nasal regurgitation of fluids

Question 39

what is the mechanisms of deglutition? aka swallowing

Answer 39

1. collecting the food and throwing it to the back of the mouth --> the tongue moves backward, sweeping over the under surface of the hard palate, collecting the chewed food 2. compacting the food bolus --> the Soft palate is depressed, tongue is elevated, the two palatoglossal arches/muscle, contract and approximate 3. squirting food bolus through oropharyngeal isthmus to the oropharynx 4. propelling the food down the oropharynx and laryngopharynx by peristalsis of superior and middle constrictors and elevation of the pharynx by the stylopharyngeus, palatopharyngeus and alpingopharyngeus 5. closure of the 3 openings --> nasopharynx by elevation of the soft palate, oropharyngeal isthmus by contraction of palatoglossal muscles, laryngeal inlet 3. expulsion of the food bolus from the laryngopharynx to esophagus by contractions of the inferior constrictor

Question 40

a cross section of the mid-pharynx, passing through the middle constrictor will not include the following layer: A. mucosa B. fibrous layer C. muscle layer D. buccopharyngeal fascia E. pharyngobasilar fascia

Answer 40

E. pharyngobasilar fascia

Question 41

which of the following structures is lateral to the pharynx? A. retropharyngeal space B. longus coli muscle C. tongue D. internal carotid artery E. none of the above

Answer 41

D. internal carotid artery

Question 42

which of the following processes the soft palate is involved in? A. blowing B. swallowing C. cough D. sneezing

Answer 42

trick question, all of the above!

Question 43

in a return visit after tonsillectomy, a patient complains that he can not feel the hot or cold drinks or the touch of food in the posterior part of his tongue. which of the following nerves is most likely injured during the surgical procedure? A. vagus nerve B. internal laryngeal nerve C. inferior laryngeal nerve D. lingual nerve E. none of the above

Answer 43

E. none of the above

Question 44

a patient comes to the clinic with a chief complaint of dysphagia and nasal regurgitation of food. You try to evoke gag reflex by touching the posterior wall of the oropharynx with a spatula but you observe no response. The sensory information of the gag reflex travel though which of the following nerves? A. vagus nerve B. glossopharyngeal nerve C. hypoglossal nerve D. trigeminal nerve E. none of the above

Answer 44

B. glossopharyngeal nerve innervation to the pharynx and soft palate is through the pharyngeal plexus of nerves located in the fascia outside the constrictor muscles. The plexus is formed by rami from: 1. vagus nerve: motor 2. glossophryngeal nerve: sensory 3. superior cervical ganglion: sympathetic

Question 45

during cough reflex, the air is prevented from going to the nasal cavity by the action of which of the muscle? A. musculus uvulae B. palatoglossus C. palatopharyngeus D. salpingopharyngeus E. stylopharyngeus

Answer 45

A. musculus uvulae

Question 46

spread of infection from the pharynx into retropharyngeal space, then into alar space is a life threatening condition that requires prompt and aggressive treatment. Inferior extension of infection from the alar space may affect which of the following structure? A. common carotid artery B. internal jugular vein C. vagus nerve D. mediastinum E. hypoglossal nerve

Answer 46

D. mediastinum

Question 47

which of the following lymph gland you need to palpate when you suspect tonsillitis? A. submental lymph nodes B. upper deep cervical (jugulodigastric) C. lower deep cervical (Jugulo-omohyoid) D. submandibular lymph nodes E. none of the above

Answer 47

B. upper deep cervical (jugulodigastric)

Question 48

the levator veli palatini arises from the cranial base and reach the soft palate inside the pharynx through: A. piercing the superior constrictor B. the gap between superior constrictor and middle constrictor C. piercing the buccopharyngeal fascia D. piercing pharyngobasilar facia E. none of the above

Answer 48

D. piercing pharyngobasilar facia

Question 49

action of which muscle of the following prevent food from regurgitation into oral cavity during swallowing? A. superior constrictor B. middle constrictor C. inferior constrictor D. palatopharyngeus E. stylopharyngeus

Answer 49

D. palatopharyngeus