A4 - ENT Flashcards
Where does the pharynx start from/ end?
From base of skull to inferior border of C6
Where does the nasopharynx start/ end?
From base of skull to soft palate
What is the nasopharynx lined with?
Ciliated pseudostratified columnar epithelium with goblet cells
Which tonsils are within the nasopharynx?
Adenoid (pharyngeal) tonsils
Tubal tonsils - lateral wall (around Eustachian tube opening)
Where does the oropharynx start/ end?
Between the soft palate and superior border of the epiglottis
What does the oropharynx contain?
-Posterior 1/3 of tongue
-Lingual tonsils (base of tongue)
-Palatine tonsils (between palatoglossal and palatopharyngeal arches of oral cavity)
-Superior constrictor muscle
What is the Weldeyer’s ring?
Ring of lymphoid tissue in the nasopharynx and oropharynx, formed by the palatine tonsils, the adenoid (pharyngeal) tonsil, tubal tonsils and the lingual tonsil
What marks the boundary between the oral cavity and oropharynx?
Palatoglossal folds (arches)
What is the name of the arched opening that opens and closes when you eat food?
Oropharyngeal isthmus - closed when food is in your mouth by depression of soft palate and elevation of the tongue
Where does the laryngopharynx start/ end?
Superior border of epiglottis to inferior border of cricoid cartilage (C6)
Where does palatoglossal muscle extend from/to?
Palatine aponeurosis of the hard palate to the tongue
Where does palatopharyngeus muscle extend from/to?
Palatine aponeurosis of the hard palate to the thyroid cartilage (pharynx)
Which tonsils are typically inflammed with tonsilitis?
Palatine
What is the arterial supply to the pharynx?
Branches of the external carotid artery:
- Ascending pharyngeal artery
- Branches of facial artery
- Branches of lingual and maxillary artery
What is the venous drainage of the pharynx?
Pharyngeal venous plexus - drains into internal jugular vein
What supplies sensory and motor innervation to the pharynx?
Sensory= glossopharyngeal nerve
Motor = vagus, apart from the stylopharyngeus (motor innervation also by glossopharyngeal)
Describe the location of the pharyngeal (adenoid) tonsil
Midline on roof of nasopharynx
Describe the location of the tubal tonsils
Around opening of the pharyngotympanic (Eustachian) tube in the lateral wall of the nasopharynx
Describe the location of the palatine tonsils
Tonsillar bed of lateral oropharynx wall, between palatoglossal arch and palatopharyngeal arch
Describe the location of the lingual tonsil
Numerous lymphoid nodules on posterior 1/3 of tongue (responsible for the irregular appearance)
What type of tissue are tonsils and what do they contain?
Mucosa-associated lymphoid tissue (MALT) - contain B cells, T cells and macrophages
Describe the location of the larynx
Suspends from the hyoid bone and spans from C3 to C6
Sits almost posteriorly to the laryngopharynx, and anterior to the oesophagus
What is the larynx composed of?
3 unpaired cartilages: cricoid, thyroid, epiglottis
3 pairs of smaller cartilages: arytenoid, corniculate and cuneiform
Fibroelastic membrane
Intrinsic muscles
What are the 3 sections of the larynx and their boundaries?
Supraglottis: inferior surface of epiglottis to vestibular folds (false vocal cords)
Glottis: contains the vocal cords and 1cm below them
Subglottis: from inferior border of the glottis to inferior border of cricoid cartilage
What arteries supply the larynx?
Superior laryngeal artery - from superior thyroid (derived ECA)
Inferior laryngeal artery - from inferior thyroid (from thyrocervical trunk)
What is the motor innervation to the larynx?
ALL BRANCHES FROM VAGUS
Recurrent laryngeal nerve: inferior branch supplies all intrinsic muscles of the larynx, except the cricothyroid
Superior laryngeal nerve: external branch supplies the cricothyroid
What is the sensory innervation to the larynx?
ALL BRANCHES FROM VAGUS
Recurrent laryngeal nerve: sensory innervation to infraglottis
Superior laryngeal nerve: internal branch provides sensory innervation to supraglottis
Which muscle helps equalise pressure in the middle ear?
Salpingopharyngeus (originates from Eustachian tube)
What do the 2 facets on the cricoid cartilage articulate with?
Superior facet - with arytenoid cartilage
Lateral facet - with inferior horn of thyroid cartilage
What is the cricoid cartilage shaped as?
A signet ring - has a ridge down middle and depressions either side
Why do males have an ‘adams apple’ but females do not?
The laryngeal prominence on the thyroid cartilage is more acute in males (90 degrees) than in females (120 degrees)
Describe the structure of the thyroid cartilage
2 lamina joined anteriorly - the site of fusion is the laryngeal prominence. The posterior margin of each lamina have a superior and inferior horn
Where is the thyroid’s facet located that articulates with the cricoid cartilage?
Medial surface of the inferior horns
Describe the structure of the arytenoid cartilages
They are pyramid shaped, and the anterior angle of the base has an elongated vocal process (where vocal ligament attaches)
What does the facet on the arytenoid cartilage articulate with?
Corniculate cartilage
Where are the cuneiform cartilages found?
Suspended in fibroelastic membrane, located anterior to the corniculate cartilages
Name the 2 thickenings of thyrohyoid membrane and where they are located
Lateral thyrohyoid ligament (2x) - posterolaterally
Medial thyroid ligament - anteromedially
What does the hypo-epiglottic ligament attach?
The hyoid bone to the anterior aspect of the epiglottis
What joins the cricoid cartilage and the trachea?
Cricotracheal ligament
What ligament can be perforated to establish an airway in an emergency where the airway is blocked above the vocal cords?
Median cricothyroid ligament - anteromedial thickening of the cricothyroid ligament joining the cricoid and thyroid cartilages
What are the extrinsic membranes/ ligaments of the larynx?
Thyroyhoid membrane - inc. medial and lateral thyrohyoid ligaments
Hypo-epiglottic ligament
Cricotracheal ligament
Median cricothyroid ligament
What are the intrinsic membranes/ ligaments of the larynx?
Cricothyroid ligament - inc. vocal ligament
Fibroelastic membrane of larynx
Quadrangular membrane (‘aryepiglottic’) - inc. vestibular ligament
Describe how the cricothyroid ligament is attached
Originates from cricoid cartilage and extends superiorly, terminates with an upper free margin.
On each side, the upper free margin is attached:
- Anteriorly to thyroid cartilage
- Posteriorly to the arytenoid cartilage
The thickening of what ligament forms the vocal ligament?
Cricothyroid ligament
What is the role of the fibroelastic membrane of the larynx?
Links together laryngeal cartilages and completes the framework of the laryngeal cavity
Where does the quadrangular membrane span from?
Between anterolateral arytenoid cartilage and lateral aspect of the epiglottis
What does the upper and lower borders of the quadrangular (aryepiglottic) membrane form?
Upper free border = aryepiglottic fold
Lower border= vestibular fold
Describe the relationship of the aryepiglottic membrane and muscle to the vocal cords (true and false)
Aryepiglottic muscle attaches from the side of the epiglottis to the arytenoid cartilages either side. The aryepiglottic membrane lies over this muscle.
Beneath it is the vestibular folds (false vocal cords) which protect the true vocal cords beneath
What forms the true vocal cords?
Free upper border of the cricothyroid membrane
What is the rima glottidis?
Opening between the true vocal cords and the arytenoid cartilages
What is the vestibule?
Space above the vocal cords (also called supraglottic cavity) - from laryngeal inlet to vestibular folds
What is the ventricle of the larynx?
The space between the true and false vocal cords
Where is the infraglottic cavity?
Below the vocal cords - between inferior aspect of vocal cords and first tracheal ring
Where is the rima vestibuli?
Between the 2 vestibular folds at the entrance to the middle chamber
What are the external muscles of the larynx?
suprahyoid group
infrahyoid group
Stylopharyngeus
What is the role of the stylopharyngeus?
Elevates the larynx
What is the laryngeal inlet?
Entrance into the larynx from the pharynx
What are the borders of the laryngeal inlet?
Anterior - free edge of epiglottis
Laterally - aryepiglottic folds
Posteriorly - cuneiform and cuniculate tubercles, interarytenoid notch
What is the function of the epiglottis?
Close off the laryngeal inlet during swallowing and prevent food entering the airway
Where does the epiglottis attach?
Posterior surface of the laryngeal prominence of the thyroid cartilage, attached by thyroepiglottic ligament
What is the role of the interarteynoid (oblique and transverse) muscles?
Adduct the vocal cords, i.e. bring them together/ closes them.
(THINK - inter = intertogether)
What is the role of the posterior cricoarytenoid muscle?
ABduct - so opens the vocal cords
(think P looks like a B lol)
What is the role of the lateral cricoarytenoid muscles?
Adduct - so closes the vocal cords
What is the role of the thyroarytenoid muscles?
Control the pitch of the voice by tightening/ loosening the vocal cords when they contract.
» When they contract = loosens the vocal cords
How does pitch change when vocal cords loosen?
Pitch gets lower
What is the role of the cricothyroid muscles?
Stretches and tenses the vocal ligaments so creates forceful speech - can alter tone of voice with the thyroarytenoid muscles
What innervates the cricothyroid muscles?
External laryngeal nerve - from superior laryngeal (derived from vagus nerve)
The thyroarytenoids, posterior + lateral cricoarytenoids, and interarytenoids are all innervated by the same nerve. Name it
Inferior laryngeal nerve - branch of recurrent laryngeal nerve (derived from vagus nerve)
Which muscles helps pull the epiglottis down when blocking the throat?
Aryepiglottic muscle
Transverse and oblique arytenoids
List the functions of the larynx
- Respiration
- Phonation (speech) - vocal cords adducted so air is forced through the closed rima glottidis, this vibrates the vocal cords and produces sound
- Effort closure - retains air in thoracic cavity during heavy lifting
- Swallowing
- Cough reflex
What is the function of the vocalis muscle?
elongates muscles lateral and parallel to the vocal ligament, so adjusts the tension in the vocal cords
What are the 2 main groups of pharyngeal muscles and what is their role?
Circular: contract sequentially from superior to inferior to propel food -> oesophagus
Longitudinal: act to shorten and widen the pharynx, and elevate the larynx during swallowing
List the muscles in the circular pharyngeal group
Superior, middle and inferior pharyngeal constrictor muscles
List the muscles in the longitudinal pharyngeal group
Stylopharyngeus
Palatopharyngeus
Salpingopharyngeus
What is the pharyngeal raphe?
Long insertion down the posterior larynx where the pharyngeal muscles insert
What is the wall of the external auditory meatus composed of?
External 1/3 = cartilage
Internal 2/3 = temporal bone
What membranes seperate the scala tympani and scala vestibule from the cochlear duct?
Basilar membrane: separates scala tympani from cochlear duct
Reissner’s membrane: separates scala vestibule from cochlear duct
What is the pars flaccida and pars tensa?
Pars flaccida - where the tympanic membrane is thin, the area above the handle of malleus
Pars tensa - where the tympanic membrane is thick and taught
Where does the cone of light shine for an otoscope of a R and L ear?
RIGHT = 4-5 o’clock
LEFT = 7-8 o’clock
Name the point of attachment of the handle of malleus to the tympanic membrane
Umbo
List the 6 walls of the middle ear
Roof (tegmental wall): tegmen tympani - petrous part of the temporal bone
Floor (jugular wall): thin layer of bone seperates ear from IJV
Lateral wall: open, tympanic membrane
Medial wall: labyrinth wall - cochlear, oval and round windows (seperates from inner ear)
Anterior wall: carotid wall - carotid canal, pharyngotympanic tube
Posterior wall: partially complete - mastoid wall (has a hole - the aditus to mastoid antrum)
What is the role of the mastoid air cells?
Act as a buffer system of air, i.e. release air into the tympanic cavity when the pressure is low
List the features of the malleus
Head, neck, lateral process, anteiror process, handle, umbo
List the features of the incus
Body, short limb, long limb
List the features of the stapes
Head, anterior limb, posterior limb, footplate (base)
How do the ossicles articulate together, joining between the tympanic membrane and the oval window?
Tympanic membrane - umbo of malleus
Head of malleus - body of incus
Long limb of incus - head of stapes
Footplate of stapes - oval window
Which ducts do the utricle and saccule receive?
Utricle - receive the 3 semi circular ducts
Saccule - receives the cochlear ducts
What do the bony and membraneous labyrinths include?
Bony = vestibule, semicircuar canals, cochlear
Membraneous = semicircular ducts, cochlear ducts and 2 sacs (utricle and saccule)
What lines the bony labyrinth?
Periosteum
What are the 3 layers of the cochlear?
Basilar membrane
Inner hair cells
Tectorial membrane with outer hair cells embedded (3x layers of OHCs)
What does the cochlear twist itself around?
Modiolus
What is the relation of the scala vestibule and scala tympani to the cochlear duct?
Scala vestibule - superior to cochlear duct, continuous with vestibule
Scala tympani - inferior to cochlear duct, terminates at round window
What is the role of the outer hair cells?
Modify hearing and protect against loud sounds, send efferent fibres from the superior olivary complex
Contains prestin motor fibres which can contract and pull the tympanic membrane to the inner hair cells
Where does endolymph drain from the utricle and saccule?
Into the endolymphatic duct
Which nerves provide sensory innervation to the external ear?
Greater auricular
Auriculotemporal (branch of V3)
What type cartilage forms the skeleton of the external ear?
Elastic cartilage
What forms the promontory (rounded projection) on the medial wall of the middle ear?
First turn of the cochlear
What level does the pharynx end and the oesophagus begin?
C6
What nerves contribute to the pharyngeal plexus?
Motor fibres from vagus
Sensory fibres from glossopharyngeal
Cervical sympathetic fibres
What are the true and false vocal cords formed by?
True = fold of upper free border of cricothyroid membrane
False= fold of lower free border of aryepiglottic membrane
Which muscles depress the larynx?
Infrahyroid muscles:
- Sternohyoid
- Sternothyroid
- Omohyoid
Which muscles elevate the larynx?
Thyrohyoid (an infrahyroid muscle) and stylopharyngeus
As well as suprahyroid muscles:
- Digastric
- Stylohyoid
- Geniohyoid
- Mylohyoid
What nerves innervate stapedius and tensor tympani muscles?
Tensor tympani - trigeminal (maxillary branch)
Stapedius - branch of facial nerve
List the steps in sound transduction from the tympanic membrane to cochlear structures
1- sound waves vibrate tympanic membrane
2- vibrations transmitted through ossicles, base of stapes vibrates the oval window
3- pressure waves generated in perilymph of scala vestibuli
4- basilar membrane is displaced
5- the hair cells of the spiral organ are displaced
6- NT released and action potentials generated in cochlear nerve
7- vibrations transferred across cochlear duct to perilymph of scala tympani
8- pressure waves dissipated by round window
