A4 - pharynx and larynx Flashcards
the pharynx is a muscular tube that connects what?
the oral and nasal cavity to the larynx and oesophagus
where does the pharynx begin and end?
begins at base of skull and ends at the inferior border of the cricoid cartilage (C6)
what are the 3 parts of the pharynx?
1) nasopharynx - posterior to the nose and superior to the soft palate
2) oropharynx - posterior to the mouth
3) laryngopharynx - posterior to the larynx
where is the nasopharynx?
between base of skull and the soft palate
the nasopharynx is continuous with the nasal cavity and performs what function?
a respiratory function by conditioning inspired air and propagating it into the larynx
the nose opens into the nasopharynx though what?
2 choanae
what is the nasopharynx lined with?
respiratory epithelium = ciliated pseudostratified columnar epithelium with goblet cells
what does the posterosuperior nasopharynx contain?
adenoid tonsils (aka pharyngeal tonsils) — enlarge between 3-8 years then regress
what does the pharyngotympanic tube do?
connects the middle ear to the nasopharynx and drains mucous from the middle ear
there is a lot of _____ tissue, which forms an incomplete _____ ring around the superior part of the pharynx. the tissue is aggregated in certain places, forming _____
there is a lot of lymphoid tissue, which forms an incomplete tonsillar ring around the superior part of the pharynx. the tissue is aggregated in certain places, forming tonsils
what is another name for the adenoids?
pharyngeal tonsils
where is the pharyngeal tonsil found?
in the mucous membrane of the roof and posterior wall of the nasopharynx
where is the tubal tonsil?
lies in the submucosa near the pharyngeal opening of the pharyngotympanic tube
what is the oropharynx bounded by?
the soft palate superiorly, the base of the tongue inferiorly, and the palatoglossal and palatopharyngeal arches laterally
where does the oropharynx extend?
from the soft palate to the superior border of the epiglottis
what type of function does the oropharynx have?
digestive
what is the oropharynx lined with?
stratified squamous epithelium
the opening of the oropharynx viewed from the mouth is called the what?
fauces
what are the palatine tonsils?
collections of lymphoid tissue on each side of the oropharynx in the interval between the palatine arches — these tonsils however do not fill the fossa between the arches in adults
what also protrudes into the oropharynx?
uvula
what is Waldeyer’s ring?
the ring of lymphoid tissue (MALT - mucosa-associated lymphoid tissue) which surrounds the naso and oropharynx. this collection of lymphoid tissue consists of the pharyngeal tonsils (adenoids), palatine tonsils and lingual tonsils. the purpose of this ring is too produce B cells, which act as the first line of defence against exogenous aggressors that have been inhaled or ingested.
the lingual tonsils are located on the dorsal surface of the base of the tongue
what does Waldeyer’s ring consist of?
- pharyngeal tonsil
- tubal tonsil x2
- palatine tonsil x2
- lingual tonsil
label
what is the laryngopharynx located between?
the superior border of the epiglottis and inferior border of the cricoid cartilage (C6)
what is posterior to the larynx?
laryngopharynx
what is the laryngopharynx lined with?
stratified squamous epithelium
what bodies is the laryngopharynx related to?
C4-C6
what muscles make up the posterior and lateral walls of the laryngopharynx?
middle + inferior pharyngeal constrictor
the larynx projects anteriorly from the laryngopharynx via what?
laryngeal inlet
what is the name of the small depression in the laryngopharyngeal cavity on either side of the laryngeal inlet?
piriforim fossa (recess)
the piriformis fossa is mucosa lined and is separated from the laryngeal inlet by what?
aryepiglottic fold
what are the 2 groups of muscles of the pharynx?
- inner longitudinal
- outer circular — pharyngeal constrictors
name the muscles of the pharynx
EXTERNAL —> pharyngeal constrictors : superior, middle and inferior
INTERNAL —> palatopharyngeus, stylopharyngeus and salpingopharyngeus
what is the main action of the external muscles of the pharynx?
constrict walls of pharynx during swallowing
what are the main actions of the internal muscles of the pharynx?
elevate (shorten and widen) pharynx and larynx during swallowing and speaking
name the 3 external pharyngeal muscles and what part of the pharynx they are in
- superior pharyngeal constrictor — in oropharynx
- middle pharyngeal constrictor — in laryngopharynx
- inferior pharyngeal constrictor — in laryngopharynx
origin, insertion and innervation of superior constrictor
O = pterygoid hamulus, pterygo-mandibular raphe, posterior end of mylohyoid line of mandible, and side of tongue
I = pharyngeal tubercle and the pharyngeal raphe
innervation = pharyngeal branch of vagus and pharyngeal plexus (CN X)
origin, insertion and innervation of middle constrictor
O = stylohyoid ligament and hyoid bone
I = pharyngeal raphe
innervation = pharyngeal plexus
origin, insertion and innervation of inferior constrictor
O = oblique line of thyroid cartilage and side of cricoid cartilage
I = pharyngeal raphe
innervation = pharyngeal plexus
name the internal muscles of pharynx
- palatopharyngeus
- salpingopharyngeus
- stylopharyngeus
origin, insertion and innervation of palatopharyngeus
O = hard palate and palatine aponeurosis
I = lateral wall of pharynx, posterior border of thyroid cartilage
innervation = pharyngeal plexus
origin, insertion and innervation of salpingopharyngeus
O = pharyngotympanic tube
I = lateral pharyngeal wall
innervation = pharyngeal plexus
origin, insertion and innervation of stylopharyngeus
O = styloid process of temporal bone
I = posterior and superior borders of thyroid cartilage with palatopharyngeus
innervation = receives motor innervation via glossopharyngeal nerve (CN IX)
which muscle of the pharynx assists in equalising pressure in the middle ear?
salpingopharyngeus
venous drainage of the pharynx?
pharyngeal venous plexus — drains into IJV
arterial supply of the pharynx?
branches of the external carotid:
- ascending pharyngeal artery
- branches of facial artery
- branches of the lingual and maxillary arteries
what does the pharyngeal plexus overlie?
the middle pharyngeal constrictor
the pharyngeal plexus supplies motor and sensory innervation to the majority of the pharynx except what?
nasopharynx
what does the pharyngeal plexus consist of?
- pharyngeal branches of CN IX
- pharyngeal branch of CN X
- branches from the external laryngeal nerve
- sympathetic fibres from the superior cervical ganglion
motor from CN X
sensory from CN IX
cervical sympathetic
the pharynx receives sensory innervation from what?
glossopharyngeal nerve = CN IX
the anterior and superior aspect of the nasopharynx is innervated by what?
maxillary nerve (V2)
the inferior aspect of the laryngopharynx (surrounding the beginning of the larynx) is innervated by what?
the internal branch of the vagus nerve CN X
motor innervation of the muscles of the pharynx is supplied by what? exception?
vagus nerve CN X — except stylopharyngeus = CN IX
the pharynx ends and the oesophagus begins at what level?
C6
identify A,B,C
A = ostium of auditory tube
B = the fold formed where the palatopharyngeus muscle underlies the mucosa
C = laryngopharynx
function of stylopharyngeus
shortens, widens and elevates the pharynx, and elevates the larynx
what is A?
What is B? what originates from the lower end of this?
what is C?
what nerve can be seen crossing A?
A = stylopharyngeus — CN IX can be seen crossing it
B = stylohyoid ligament — middle pharyngeal constrictor originates from lower end of this
C = posterior wall of larynx
what are A-D?
A = IJV
B = cervical sympathetic chain
C = vagus nerve
D = pharyngeal plexus
how does the internal jugular vein start and end?
- starts as a continuation of the sigmoid sinus
- ends when it unites with the subclavian vein to from the brachiocephalic vein
what does the cervical sympathetic chain contain?
preganglionic sympathetic fibres
what does the vagus nerve pass throguh?
jugular foramen
name 3 components of the pharyngeal plexus
- motor fibres from vagus
- sensory fibres from glossopharyngeal
- cervical sympathetic fibres
describe the location of the larynx
- anterior compartment of neck
- level of C3-C6 vertebrae
- continuous inferiorly with the trachea, and opens superiorly into the laryngeal part of the pharynx
- suspended from the hyoid bone
- oesophagus is posterior to the larynx
the larynx is covered anteriorly and laterally by what?
- anteriorly — infrahyoid muslces
- laterally — lobes of the thyroid gland
what are the functions of the larynx?
> voice production
guard the air passages, esp during swallowing when it serves as the “sphincter” or “valve” of the lower respiratory tract — thus maintaining a patent airway
what makes up the laryngeal skeleton?
9 cartilages:
- 3 single = thyroid, cricoid and epiglottic
- 3 paired = arytenoid, corniculate, cuneiform
which is the largest laryngeal cartilage?
thyroid
what does the superior border of the thyroid cartilage lie opposite to?
C4 veretbra
describe the thyroid cartilage
- composed of 2 sheets (laminae) which join anteriorly to form the laryngeal prominence (Adam’s apple)
- the posterior border of each lamina projects superiorly as the superior horn and inferiorly as the inferior horn
the superior and inferior horns of the thyroid cartilage attach to the hyoid by what?
thyrohyoid membrane
describe the thyrohyoid membrane
- the superior border and superior horns attach to the hyoid by the thyrohyoid membrane
- the thick median part of this membrane is the median thyrohyoid ligament
- its lateral parts are the lateral thyrohyoid ligaments
the inferior horns of the thyroid cartilage articulate with what?
cricoid cartilage at the cricothyroid joints
what are the main movements of the cricothyroid joints?
rotation and gliding of thyroid cartilage, resulting in changes in the length of the vocal cords
describe the cricoid cartilage
- a complete ring of hyaline cartilage, consisting of a broad sheet posteriorly and a much narrower arch anteriorly (said to look like a signet ring)
- completely encircles the airway
- small, but very thick and strong
the inferior border of cricoid cartilage is at what level?
C6
what does the cricoid cartilage articulate with posteriorly?
the paired arytenoid cartilages
via what does the cricoid cartilage attach to the inferior margin of the thyroid cartilage and the first tracheal ring?
- attaches to inferior margin of thyroid cartilage by median cricothyroid ligament
- attaches to 1st tracheal ring by cricotracheal ligament
what type of cartilage is in the epiglottis?
elastic
what marks the entrance to the larynx?
epiglottis
what is the ‘stalk’ of the epiglottis attached to?
the back of the anterior aspect of the thyroid cartilage
what happens to the epiglottis during swallowing?
it flattens and moves posteriorly to close off the larynx and prevent aspiration
describe the arytenoid cartilages
- pyramidal shaped
- sit on the cricoid cartilage
- consist of an apex, base, 3 sides and 2 processes
describe the apex of the arytenoid cartilages
articulates with the corniculate cartilages and attaches to the aryepiglottic fold
describe the base of the arytenoid cartilages
articulates with the superior border of the cricoid cartilage
what does the vocal process of the arytenoid cartilages provide attachment for?
vocal ligament
what does the muscular process of the arytenoid cartilages provide attachment for?
the posterior and lateral cricoarytenoid muscles
describe the crico-arytenoid joints
- located at the bases of the arytenoid cartilages and the superolateral surfaces of the lamina and cricoid cartilage
- permit the arytenoid cartilages to slide toward or away from one to another, and to tilt anteriorly and posteriorly, and to rotate —these movements are important in approximating, tensing and relaxing the vocal folds
describe the corniculate cartilages
- minor cartilaginous structures
- articulate with the apices of the arytenoid cartilages
describe the cuneiform cartilages
- located within the aryepiglottic folds
- have no direct attachment, but act to strengthen the folds
what level can the hyoid bone be palpated at?
C3
the thyroid cartilage can be palpated at what level?
C4-C5
the cricoid cartilage can be palpated at what level?
C6-C7
what happens to the larynx in swallowing and what is the effect of the backwards motion of the tongue?
during swallowing, the larynx is elevated and the backward motion of the tongue forces the epiglottis over the glottis’ opening
what is the inferior surface of the larynx lined with? exception?
- pseudostratified ciliated columnar epithelium
- exception is the true vocal cords — lined by a stratified squamous epithelium
arterial supply of the larynx?
- superior laryngeal artery
- inferior laryngeal artery
what do the superior and inferior laryngeal arteries follow into the larynx?
superior laryngeal and recurrent laryngeal nerves respectively
venous drainage of larynx?
superior and inferior laryngeal veins
where do the superior and inferior laryngeal veins drain?
superior laryngeal —> superior thyroid —> IJV
inferior laryngeal —>inferior thyroid —> left brachiocephalic
innervation of the larynx?
—> receives both motor and sensory by branches of the vagus nerve
- recurrent laryngeal nerve — sensory innervation to infraglottis and motor innervation to all the internal muscles of larynx (except the cricothyroid)
- superior laryngeal nerve — the internal branch provides sensory innervation to the supraglottis and the external branch provides motor innervation to the cricothyroid
where does the thyrohyoid membrane extend from?
the thryoid cartilage to the hyoid bone
the thyrohyoid membrane is thickened both medially and laterally to form what?
medial and lateral thyrohyoid ligaments
what does the cricothyroid membrane attach to inferiorly?
the upper border of the cricoid cartilage
what is the cricothyroid membrane attached to anteriorly in the midline?
the inferior border of the thyroid cartilage (cricothyroid ligament)
what does the free upper border of the cricothyroid membrane form?
the vocal folds (true vocal cords)
what is the aryepiglottic (quadrangular/quadrate) membrane attached to inferiorly and superiorly?
- inferiorly — the body and apex of the arytenoid
- superiorly — sides of the epiglottis
what do the upper and lower free borders of the aryepiglottic membrane form?
- free upper border forms the aryepiglottic fold (part of the laryngeal inlet)
- free lower border forms the vestibular fold (false vocal cord)
describe the vestibular fold (false vocal cord)
- fixed folds
- act to provide protection to the larynx
- lie superiorly to the true vocal cords
- consist of the vestibular ligament (free lower edge of the aryepiglottic/quadrangular membrane), covered by a mucous membrane
- pink in colour
what are the 3 main regions of the larynx?
- supraglottic cavity (laryngeal vestibule)
- ventricle
- infraglottic cavity
where does the supraglottic cavity (laryngeal vestibule) extend from?
the laryngeal inlet to the vestibular folds
where does the ventricle (saccule) of the larynx extend?
- superiorly from the free edge of the vestibular fold to the straight margin of the vocal fold inferiorly
- extends laterally from the middle part of the laryngeal cavity
where does the infraglottic cavity extend?
the vocal folds to the inferior border of the cricoid cartilage, where it is continuous with the lumen of the trachea
what is the laryngeal inlet formed by anteriorly, posterity and laterally?
- anteriorly — the free curved edge of the epiglottis
- posteriorly — the arytenoid cartilages, the corniculate cartilages, and the interarytenoid fold
- laterally — the aryepiglottic fold
describe the varying mucosa of the larynx
- the mucosa differs throughout the larynx according to regional function
- from the laryngeal inlet, epithelium is mainly pseudostratified ciliated columnar with varying numbers of mucous glands:
- surpraglottic cavity — N/A
- vestibular folds — a few seromucous glands
- ventricle — contains numerous glands, as well as a
considerable amount of lymphatic tissue
- vocal folds — covered in stratified squamous epithelium. no
mucous glands
- infraglottic cavity — has some glands
what are the 2 categories of the muscles of the larynx?
intrinsic and extrinsic
name the extrinsic muscles of the larynx and what they do
suprahyoid and infrahyoid — serve to elevate of depress the larynx during swallowing
name the muscles of the larynx
- cricothyroid
- thyro-arytenoid
- posterior crico-arytenoid
- lateral crico-arytenoid
- transverse and oblique arytenoids
- vocalis
innervation of intrinsic laryngeal muscles?
recurrent laryngeal innervates all but cricothyroid = external laryngeal nerve (from CN X)
cricothyroid muscle function
increases length and tension of the vocal cords — pitch of voice
thyro arytenoid muscle function
relaxes vocal ligament
posterior cricoarytenoid muscle function
ABduct vocal folds = only muscle to abduct vocal cords
which muscles ADduct the vocal cords?
transverse, lateral and oblique cricoarytenoid
the glottis is formed from the combination of what?
the vocal folds and the space in between the vocal folds (rima glottidis)
- A = vocal process of arytenoid cartilage
- posterior attachment of vocal cord
- lamina
- hyoid
- aryepiglottic/quadrangular membrane
- aryepiglottic
- vestibular fold/false vocal cord
- cricothyroid membrane
- vocal cord
- arch
- angle
- transverse arytenoid
- A = posterior cricoarytenoid
- abducts the vocal cords
- transverse arytenoid / interarytenoid
- approximates arytenoid cartilages to adduct the vocal cords
- recurrent laryngeal nerve
- all except cricothyroid
- internal branch of the superior laryngeal nerve
- recurrent laryngeal nerve
- recurrent laryngeal
- cricothyroid muscle
- internal laryngeal
- glottis/rima glottis
- epiglottis
- aryepiglottic
- piriform recess/fossa
- cricothyroid
- increases length and tensions of vocal cords — therefore pitch of voice
- external laryngeal nerve (branch of superior laryngeal nerve)
relationship between recurrent laryngeal nerve and the inferior thyroid artery?
recurrent laryngeal nerve goes OVER the inferior thyroid artery
what muscle inserts into the pharyngeal tubercle and the pharyngeal raphe?
superior constrictor
what muscle originates from the stylohyoid ligament and hyoid bone?
middle constrictor
what are aggregations of lymphoid tissue located between the pharyngeal arches?
palatine tonsils
what is located in the wall of the roof and posterior wall of the pharynx, and is commonly referred to as the adenoids?
pharyngeal tonsil
what part of the pharynx is lined by pseudostratified ciliated columnar epithelium?
nasopharynx
what is bounded superiorly by the uvula and inferiorly by the tip of the glottis?
oropharynx
what is continuous with the oesophagus?
laryngopharynx
the stylopharyngeus receives motor innervation via what?
CN IX
what muscle originates from the pharyngotympanic tube and so assists in equalising pressure in the middle ear?
salpingopharyngeus
what muscle is part of the inferior constrictor, and prevents air entering the oesophagus between swallows?
cricopharyngeus
Some of the upper fibres of the superior constrictor muscle combine with fibres of the palatopharyngeal muscle to form ________
Passavant’s ridge
what 3 layers does the wall of the pharynx consist of?
Innermost - mucosal layer - the type of epithelium is dependent on location
Middle - fibromuscular layer which is comprised of the pharyngobasilar fascia, pharyngeal raphe and muscles (see below)
Outermost - the buccopharyngeal fascia which contains nerves and vessels
what is the buccopharyngeal fascia of the pharynx continuous with inferiorly?
pretracheal fascia
what does the posterior wall of the pharynx lie against?
the prevertebral layer of deep cervical fascia
