The Pharynx and Larynx

Question 1

Describe the muscles of the pharynx

Answer 1

External layer of circular muscle (superior, middle inferior)
Inner layer of longitudinal muscle

Question 2

Describe the external layer of muscle in the pharynx

Answer 2

Composed of 3 constrictor muscles that overlap each other
Superior, middle, inferior constrictors
Contract superior to inferior to swallow down

Question 3

What happens during swallowing?

Answer 3

Tongue pushes food from oral cavity into oropharynx
Soft palate rises and closes off nasopharynx
Food enters laryngopharynx
Constriction of muscles of pharyngeal wall move food into oesophagus

Question 4

What does the epiglottis do during swallowing?

Answer 4

It is a cartilage of the pharynx
It closes off the laryngeal inlet
Prevents food or liquids entering larynx

Question 5

What are the 3 parts of the pharynx?

Answer 5

Nasopharynx - posterior to nasal cavity
Oropharynx - posterior to oral cavity
Laryngopharynx - posterior to larynx

Question 6

What are tonsils?
How many tonsils?

Answer 6

Collections of lymphoid tissue
4
Pharyngeal
Tubal
Palatine
Lingual

Question 7

Tonsils in the nasopharynx?

Answer 7

Pharyngeal tonsil (adenoid) is at the roof of the nasopharynx

Tubal tonsil surrounds opening of auditory tube.

Question 8

Tonsils in the oropharynx?

Answer 8

Palatine tonsil - next to the pharyngeal wall in the oropharynx

Question 9

Where is the lingual tonsil?

Answer 9

On the posterior aspect of the tongue

Question 10

What is the pharynx innervated by?

Answer 10

Sensory fibres from the glossopharyngeal nerve
Motor fibres from the vagus nerve

Question 11

What nerves lie close to the posterior pharyngeal wall?

Answer 11

Sympathetic trunk (+cervical ganglion)
Superior laryngeal nerve (branch of vagus nerve) descends over posterior aspect of the internal carotid artery, passes between inferior and middle constrictors
Hypoglossal nerve(XII) close to vagus nerve
Glossopharyngeal nerve(IX) deep to internal carotid artery

Question 12

Pharynx and gag reflex

Answer 12

Gag reflex protects airway
Mediated by vagus and glossopharyngeal
IX carries sensory input to CNS
Motor fibres in X stimulates muscles of the soft palate and pharynx to contract

Question 13

How can there be swallowing difficulties if a stroke affects regions of the brain involved in swallowing?

Answer 13

In normal swallowing, vagus causes contraction of pharyngeal muscles and soft palate also conveys sensation from larynx.
Glossopharyngeal conveys sensory info from larynx

Interruptions of these pathways cause dysfunctional swallowing.
Loss of sensation impairs cough reflex.
Risk of aspiration - swallowed food passing into lungs, causing infection

Question 14

Describe the laryngeal skeleton

Answer 14

9 cartilages
3 unpaired
3 pairs

Connected by membranes and very small joints

Question 15

Name the three unpaired cartilages in the larynx

Answer 15

Epiglottis
Thyroid
Cricoid
Larger than paired cartilages

Question 16

Name the three paired cartilages in the larynx

Answer 16

The arytenoids
The cuneiforms
The corniculate

Much smaller than unpaired cartilages, latter 2 are very small

Question 17

Describe the thyroid cartilage

Answer 17

Composed of laminae - 2 flat cartilages that meet in the anterior midline to form laryngeal prominence (adams apple)

Posteriorly the laminae form extensions projecting superiorly and inferiorly
The superior and inferior horns

Superior horns attach to hyoid bone
Inferior horns articulate with the cricoid cartilage below

Question 18

What is the cricothyroid membrane?

Answer 18

Connects inferior border of thyroid and superior border of cricoid. It can be pierced to create an emergency airway.

Question 19

Describe the epiglottis cartilage

Answer 19

Attached to superior aspect of thyroid cartilage where the thyroid laminae meet

Covers laryngeal inlet during swallowing

Question 20

Describe the arytenoids

Answer 20

Sit on superior cartilage of cricoid cartilage
Articulate with it at small joints
Vital for phonation, as the vocal chords attach to them
Movement of arytenoids moves vocal chords

Question 21

What is the internal aspect of the larynx modified for?

Answer 21

Modified for phonation
Intrinsic muscles of larynx move laryngeal cartilages, moving the vocal chords

Question 22

What are the two pairs of folds projecting into the cavity of the larynx?

Answer 22

Vestibular folds (false vocal chords) superiorly

Vocal folds (true vocal chords) inferiorly

Both are folds of mucous membrane

Question 23

Describe the true vocal chords in the larynx

Answer 23

Vocal folds (folds of mucous membrane) cover and protect the vocal ligaments.

Vocal ligaments attach anteriorly to the internal aspect of laryngeal prominence and posteriorly to arytenoid cartilages

Question 23

Describe action of vocal chords and rima glottidis during phonation

Answer 23

Phonation - adduction of vocal chords and closure of rima glottidis

Abduction opens the rima glottidis…
- a small degree in whispering
- partially in normal breathing
- fully in forced breathing

Question 23

What is the space between the vocal chords called?

Answer 23

Rima glottidis
Closed when vocal chords adduct
Opened when vocal chords abduct

Question 24

What muscles act upon the larynx?

Answer 24

Extrinsic and intrinsic

Question 25

Describe extrinsic muscles in the larynx

Answer 25

Suprahyoid and infrahyoid muscles
Move the larynx as a whole during speech and swallowing instead of individual cartilages

Question 26

Describe the intrinsic muscles in the larynx

Answer 26

Move the laryngeal cartilages, so also vocal chords
Include the…
- l/r cricothyroid muscles anteriorly, places tension on vocal chords
- l/r posterior cricoarytenoids on posterior surface of cricoid, abduct vocal chords to open rima glottidis
- transvere arytenoid - unpaired on posterior aspect of larynx, connects two arytenoids, adduct vocal chords to close rima glottidis

Question 27

Describe innervation of the larynx

Answer 27

2 nerves - both branches of vagus

Superior laryngeal nerve - innervates cricothyroid, sensory to the larynx above the vocal chords

Recurrent laryngeal - innervates all the intrinsic muscles, sans cricothyroid, sensory to larynx below the vocal chords

Question 28

What structures in the neck are palpable upon examination?[7]

(bone, cartilage,membrane, gland, pulse)

Answer 28

Hyoid bone inferior to mandible
Thyroid cartilage
Cricoid cartilage, inferior to thyroid cartilage
First tracheal cartilage inferior to cricoid
Cricothyroid membrane (emergency airway)
Lobes of thyroid gland either side of upper trachea and inferior larynx
Carotid pulse - best just anterior to sternocleidomastoid at level of thyroid cartilage