ENT Flashcards
Where is the inner ear located? 2 main components of the inner ear? 2 openings into the middle ear covered by membranes?
Within the petrous part of the temporal bone between the middle ear and internal acoustic meatus lying laterally and medially
Bony and membranous labyrinthes
Oval window + round window: oval= between middle ear and vestibule + round window between middle ear from scala tympani
What does the bony labyrinth consist of? Membranous labyrinth?
A series of bony cavities= the cochlea, vestibule and 3 semi-circular canals, lined internally with periosteum and contains perilymph
Lies within the bony labyrinth= cochlear duct, semi-circular ducts, utricle and the saccule, contains endolymph
The vestibule communicates anteriorly with what and posteriorly with what? 2 parts of the membranous labyrinth contained within the vestibule?
The cochlea and semi-circular canals
The saccule and utricle
The cochlea houses what? It twists upon itself around what producing a cone shape which points in what direction? What’s found at the base of the modiolus?
The cochlea duct of the membranous labyrinth
The modiolus
Branches from the cochlear portion of the vestibulocochlear nerve
What extends outwards from the modiolus and attaches to the cochlear duct? Two perilymph-filled chambers above and below this?
Spiral lamina
1) Scala vestibuli= superiorly
2) Scala tympani= inferiorly terminating at the round window
3 semi-circular canals? Contain what? Swelling at one end called what?
Anterior, lateral and posterior
Semi-circular ducts for balance- along with utricle and saccule
Ampulla
Lateral wall of the cochlear duct formed by what? The roof formed by what which separates it from the scala vestibuli? The floor formed by a membrane which separates it from the scala tympani? The basilar membrane housing the epithelial cells of hearing called what?
Thickened periosteum- the spiral ligament
Reissner’s membrane
The basilar membrane
The Organ of Corti
The utricle receives what? The saccule receives what? Endolymph drains from here into what? Travels through what to the posterior aspect of the petrous part of the temporal bone? The saccule detects linear acceleration in what plane? The utricle?
The 3 semi-circular ducts
The cochlear duct
The endolymphatic duct
The vestibular aqueduct
The vertical plane without tilting
The horizontal plane without tilting
Sensory receptors where detect change in speed and/ or direction of flow of endolymph within the semi-circular ducts? The semi-circular ducts detect what?
Sensory receptors in the ampullae of the semi-circular canals
Rotational movement in any direction
The bony labyrinth receives its blood supply from what 3 arteries? Membranous labyrinth? Venous drainage?
1) Anterior tympanic branch
2) Petrosal branch
3) Stylomastoid branch
Labyrinthine artery(branch of the inferior cerebellar artery)–> cochlear branch + x2 vestibular branches
The labyrinthine vein–> the sigmoid sinus/ inferior petrosal sinus
Inner ear is innervated by what? Vestibular nerve enlarges and splits into what to supply what? Cochlear nerve?
The vestibulocochlear nerve via the internal acoustic meatus–> vestibular + cochlear nerve
The vestibular ganglion–> superior and inferior parts to supply the utricle, saccule and 3x semi-circular ducts
The base of the modiolus through the lamina to supply the receptors of the Organ of Corti
Main function of the middle ear? 2 main parts of the middle ear? Tympanic cavity contains what 3 small bones?
To transmit vibrations from the tympanic membrane to the inner ear via the auditory ossicles
1) Tympanic cavity- medial to the tympanic membrane: malleus, incus and stapes
2) Epitympanic recess= space superior to the tympanic cavity next to the mastoid air cells, the malleus and incus partially extend upwards into the epitympanic recess
Roof of the middle ear separates it from what? Floor? Lateral wall made up of what? Medial wall? Anterior wall has two openings for what? Separated from what? Posterior wall consists of what? Hole in this superiorly?
Thin bone from petrous part of temporal bone- middle cranial fossa
“Jugular wall”- from internal jugular vein
The tympanic membrane and lateral wall of the epitympanic recess
Lateral wall of the internal ear- prominent bulge from the facial nerve
For the auditory tube and tensor tympanic muscle, from the inner carotid artery
Between the tympanic cavity + mastoid air cells
The aditus to the mastoid antrum
Which bone is the largest and most lateral attaching to the tympanic membrane via what? The head of this lies where and articulates with what? Consists of what and what articulates with the malleus, posterior wall of the middle ear and the stapes?
The malleus via the handle of malleus
In the epitympanic recess–> the incus
A body and two limbs
The body, the short limb and the long limb
The stapes consists of what?
Joins the incus to the oval window, is stirrup-shaped, has a head, 2 limbs and a base
Head–> the incus, base–> the oval window
The mastoid air cells are located where? They are what? Act as what?
Posterior to the epitympanic recess
Collection of air-filled spaces in the mastoid process of the temporal bone, contained within the mastoid antrum–> middle ear via the aditus
A buffer system of air- releasing air into the tympanic cavity when the pressure is too low
2 muscles serving a protective function in the middle ear? Contract in response to what? Known as what? The tensor tympanic originates where? Innervated by what? Stapedius muscle?
1) Tensor tympanic + stapedius
Loud noise
Acoustic reflex
From the auditory tube–> the handle of malleus pulling it medially
Tensor tympanic nerve(branch of the mandibular nerve)
Facial nerve- attaches to the stapes
What connects middle ear to the nasopharynx? Acts to do what? Lined with what? Innervated by what? Blood supply?
Eustachian tube
Equalise the pressure of the middle ear to that of external auditory meatus
Mucous membrane
Branches of tympanic plexus
Ascending pharyngeal artery from ex car artery, middle meningeal artery + artery of the pterygoid canal(branches of maxillary artery)
Drains into pterygoid venous plexus
2 parts of external ear? Ends where?
Auricle/ the pinna
External acoustic meatus
Tympanic membrane
Outer curvature of the auricle? Second innermost curvature? Divides into what? Hollow depression in the middle? Continues as what? Opposite the tragus?
Helix
Antihelix
Inferoanterior and superoposterior crus
Concha
External acoustic meatus
Antitragus
Walls of external 1/3 of ex ac meatus formed by what? Inner 2/3? Direction of path?
Cartilage–> the temporal bone
Superoanterior direction–> turns slightly to move superoposteriorly- ends by running inferoanterior
Structure of tympanic membrane? Attaches to the handle of malleus at what? What can be seen at handle of malleus’ highest point? Parts moving away from the lateral process?
Covered with skin and mucous membrane on the inside
Connected to the temporal bone by a fibrocartilaginous ring (annulus)
A point called the umbo of tympanic membrane
The lateral process of the malleus
Anterior and posterior malleolar folds
Supply of external ear? Sensory innervation of auricular skin?
Posterior auricular artery, superficial temporal artery, occipital artery, maxillary artery
Great auricular nerve, lesser occipital nerve, auriculotemporal nerve, branches of facial and vagus nerves
Functions of the nose?
Conditioning the air to maximise gas exchange, raising temperature + humidity
Hairs catch large foreign particles
Defence function= cilia take particulates backwards to be swallowed
Structure of nasal cavity?
Anterior= nasals–> enlarged vestibule, skin lined with stiff thick hairs
Turbinates= soft vascular tissue within nose increases SA of nasal cavity to warm + moisten air
Superior meatus: olfactory epithelium, cribriform plate, sphenoid sinus
Middle meatus: sinus openings
Inferior meatus: nasolacrimal duct- drains tears from eye to be swallowed
Epithelium lining nasal entrance? Rest?
Keratinised columnar
Non-keratinised columnar
4 paranasal sinuses? Each is lined by what?
Frontal
Maxillary
Ethmoid
Sphenoid
Ciliated pseudostratified epithelium interspersed with mucus- secreting goblet cells
Bone of frontal sinus? Position? Nerve? Drainage?
Frontal
Above the eyes into 2 by midline septum
Ophthalmic div of V(V1)
Hiatus semilunaris of middle meatus
Bone of maxillary sinus? Position? Nerve? Drainage?
Body of maxilla
Just under the eyes/ orbit–> pyramidal shape
Hiatus semilunaris of the middle meatus
Bone of ethmoid sinus? Position? Nerve? Drainage?
Labyrinth of air cells between the eyes
3 types= anterior, middle and posterior
Ethmoid bone
V1
Anterior = hiatus semilunaris into the middle meatus, middle= ethmoid bullar, posterior = superior meatus
Bone of sphenoid sinus? Position? Nerve? Drainage?
Medial to cavernous sinus
Sphenoid bone
V1
Sphenoethmoidal recess lateral to attachment of the nasal septum
3 divisions of the nasal cavity?
Vestibule= area surrounding anterior external opening
Respiratory region= lined by ciliated pseudostratified epithelium interspersed with mucus-secreting goblet cells
Olfactory region at apex of cavity- lined by olfactory cells with olfactory receptors
Curved shelves of bone that project out of the lateral walls of the nasal cavity? Create what for air to flow? Function of conchae?
Conchae= inferior, middle and superior
Inferior, middle + superior meatus and spheno-ethmoidal recess recess
Increase SA of cavity + disrupts fast air flow–> air more humidified
Other 2 structures that open into the nasal cavity other than the sinuses?
Nasolacrimal duct- opens into inferior meatus
Auditory tube= opens into nasopharynx at level of inferior meatus
Internal and external carotid branches supplying the nose?
Internal= anterior
and posterior ethmoidal arteries(branches of ophthalmic artery descend through cribriform plate)
Sphenopalatine, greater palatine, superior labial and lateral nasal sinuses
Special and general innervation of the nose?
Olfactory nerves
Nasopalatine (branch of maxillary) nerve + nasociliary(branch of ophthalmic) nerve, external= trigeminal nerve
General sensation in the anterior 2/3 of the tongue is supplied by what? Taste? Touch and taste of posterior 1/3 by what nerve?
Sensation= trigeminal nerve
Taste= facial nerve
Glossopharyngeal nerve
Where does the pharynx start and finish? 3 parts?
From the base of the skull–> the inferior border of the cricoid cartilage
Nasopharynx, oropharynx, laryngopharynx
Where is the nasopharynx found? Lined with what? Posterosuperior part contains what?
Between the base of the skull and the soft palate- continuous with the nasal cavity
Ciliated pseudostratified columnar epithelium with goblet cells
The adenoid tonsils- grow between 3-8 years of age then regress
What is the oropharynx bounded by anteriorly and posteriorly? Contains what structures? Ring of lymphoid tissue in naso and oropharynx formed by paired palatine tonsils, adenoids and lingual tonsil?
Soft palate and constrictor muscles
Posterior 1/3 of the tongue
Lingual tonsils- lymphoid tissue at the base of the tongue
Palatine tonsils= lymphoid tissue in the tonsillar fossa
Superior constrictor muscle
Waldeyer’s ring
What is the arch across the oropharynx that runs on either side, lateral and forward to the side of the base of the tongue? Formed by the projection of what muscle?
Palatoglossal fold
Palatoglossus muscle
Where is the laryngopharynx located? Communicates with the larynx via what? Lateral to which what can be found? Contains what muscles?
Between the superior border of the epiglottis and inferior border of the cricoid cartilage
The laryngeal inlet
Piriform fossae
The middle and inferior pharyngeal constrictors
3 circular pharyngeal constrictor muscles of the pharynx? All innervated by what nerve? All fuse together on what? Arterial supply?
Superior, middle and inferior
Vagus nerve
Pharyngeal artery
Origin of superior pharyngeal constrictor? Inserts into what?
Pterygomandibular ligament, alveolar process of mandible and medial pterygoid plate + pterygoid hamulus of the sphenoid bone
Into the pharyngeal tubercle of the occiput and median pharyngeal raphe
Origin of middle pharyngeal constrictor? Inserts into what?
Stylohyoid ligament + horns of the hyoid bone
Into the pharyngeal raphe
Origin of inferior pharyngeal constrictor? Inserts into what?
Superior component= oblique fibres–> thyroid cartilage
Inferior= horizontal fibres–> the cricoid cartilage
Longitudinal muscles of the pharynx?
Stylopharyngeus, palatopharyngeus, salpingopharyngeus
Origin, insertion and innervation of stylopharyngeus?
Palatopharyngeus? Salpingopharyngeus?
Styloid process
Thyroid cartilage
CN IX
From Eustachian tube
CN X
From Eustachian tube
CN X
Motor and sensory innervation of the majority of the pharynx? Overlies which muscle?
Pharyngeal plexus: pharyngeal branches from CN IX, pharyngeal branch of the vagus nerve, branches from the external laryngeal nerve, sympathetic fibres from the superior cervical ganglion
Sensory= CN IX
Motor= CN X, except for stylopharyngeus which is CN IX
Arterial supply to the pharynx? Venous drainage?
Branches of the external carotid artery
Ascending pharyngeal artery
Branches of the facial artery
Branches of the lingual and maxillary arteries
Pharyngeal venous plexus–> internal jugular vein
What are the carotid sheaths? Contents? Fascia of the sheath? Column of fascia runs between where?
Paired structures on either side of the neck, which enclose an important neurovascular bundle of the neck
1) Common carotid artery
2) Internal jugular vein
3) Vagus nerve
4) Accompanying cervical lymph nodes
Contributions from the pretracheal, prevertebral, and investing fascia layers
Base of the skull–> thoracic mediastinum
Functions of the larynx? Situated where?
Protects the lower airway, voice production, coughing, sensory organ + controls ventilation
Below the tongue and the hyoid bone and between the great vessels of the neck between C3-C6
Larynx covered anteriorly by what? Laterally? Posteriorly? What is Sellick’s manoeuvre?
Infrahyoid muscles
Thyroid gland lobes
Oesophagus
Pressure applied to the cricoid cartilage of the larynx to occlude the oesophagus to prevent regurgitation of gastric contents during emergency intubation
Internal larynx can be divided into what 3 sections?
Supraglottis= from inferior epiglottis–> vestibular folds
Glottis= contains vocal cords and 1cm below them
Subglottis= from inferior glottis–> inferior border of the cricoid cartilage
Interior surface of the larynx is lined by what?
Pseudostratified ciliated columnar epithelium
True vocal cords= stratified squamous epithelium
Vasculature and drainage of the larynx?
1) Superior laryngeal artery= branch of superior thyroid artery(external carotid,) follows superior laryngeal nerve
2) Inferior laryngeal artery= branch of inferior thyroid artery (thyrocervical trunk,) follows recurrent laryngeal nerve
Superior + inferior laryngeal veins- superior= into internal jugular vein, inferior= into left brachiocephalic vein
Innervation of the larynx?
1) Recurrent laryngeal nerve= sensory–> infraglottis + motor innervation–> internal muscles of the larynx (except cricothyroid)
2) Superior laryngeal nerve- internal branch sensory–> supraglottis, external branch= motor–> cricothyroid
How many cartilages within the larynx? 3 unpaired? 6 paired?
9; 3 unpaired + 6 paired
Epiglottis, thyroid, cricoid
Cuneiform, corniculate, arytenoid
2 sheets join anteriorly for the thyroid cartilage to form what? Posterior border of each sheet project superiorly and inferiorly to form what? Superior horns connect to hyoid bone via what? Inferior horns?
Laryngeal prominence
Superior + inferior horns
Lateral thyrohyoid ligament
Cricoid cartilage
Cartilage type of the cricoid cartilage? Marks the inferior border of the larynx at what level? Articulates with what posteriorly to change what?
Hyaline
C6
Arytenoid cartilages- length of vocal cords affecting the sound produced
Cartilage type of the epiglottis? Its ‘stalk’ is attached to the back of anterior of what?
Elastic covered in a mucous membrane
Thyroid cartilage
Arytenoid cartilages consist of what? Where are the cuneiform cartilages located?
Apex–> corniculate cartilage
Base–> superior cricoid cartilage
Vocal process= attaches vocal ligament
Muscular process= for posterior and lateral cricoarytenoid muscles
Within the aryepiglottic folds- act to strengthen them
Function of extrinsic and intrinsic laryngeal ligaments?
Attach components to external structures e.g. hyoid and cricoid cartilage
Holds cartilages of the larynx together
4 extrinsic laryngeal ligaments?
Thyrohyoid membrane= between superior thyroid cartilage and hyoid bone
a) Median thyrohyoid ligament= anteromedial thickening
b) Lateral thyrohyoid ligaments= posterolateral thickenings
Hyo- epiglottic ligament= hyoid bone–> anterior epiglottis
Cricotracheal ligament= cricoid cartilage–> trachea
Median cricothyroid ligament= connects cricoid and thyroid cartilages
2 intrinsic laryngeal ligaments?
1) Cricothyroid ligament- forms vocal ligament, attached anteriorly to thyroid cartilage, posteriorly to arytenoid cartilage
2) Quadrangular membrane= anterolateral arytenoid cartilage–> lateral epiglottis, lower margin= thickened–> vestibular ligament
The 2 important soft tissue folds within the larynx? How are the true vocal cords structured? Space between the folds?
Vestibular + vocal folds
Non-keratinised stratified squamous epithelium
Reinke’s space= watery layer rich in glycosaminoglycans
Vocal ligament= at free upper edge of cricothyroid ligament
Vocalis muscle= fine fibres lateral to vocal ligaments
Rima glottidis
Vestibular folds lie where? Consist of?
Superiorly to true vocal cords
Vestibular ligament covered by mucous membrane- pink, fixed folds act to provide protection to larynx
All intrinsic muscles of the larynx are innervated by what? Cricothyroid muscle?
Inferior laryngeal nerve
External branch of the superior laryngeal nerve
Function of cricothyroid muscle? Attachments, actions and innervation?
Stretches and tenses vocal ligaments- creates forceful speech + altering tone
Cricoid cartilage–> inferior horn thyroid cartilage
External branch of superior laryngeal nerve
Function of thyroarytenoid muscle? Attachments, actions and innervation?
Relaxes vocal ligament–> softer voice
Inferoposterior thyroid cartilage–> anterolateral arytenoid cartilage
Inferior laryngeal nerve
Function of posterior cricoarytenoid muscle? Attachments, actions and innervation?
Sole abductors of the vocal folds- widens rima glottidis
From posterior cricoid cartilage–> muscular arytenoid cartilage
Inferior laryngeal nerve
Function of lateral cricoarytenoid muscle? Attachments, actions and innervation?
Major adductors of the vocal folds- narrows the rima glottidis- modulating tone + volume of speech
From arch of cricoid cartilage–> muscular arytenoid cartilage
Inferior laryngeal nerve
Function of transverse and oblique arytenoid muscles? Attachments, actions and innervation?
Adduct the arytenoid cartilages closing posterior rima glottidis- narrowing laryngeal inlet
From one arytenoid–> opposite arytenoid
Inferior laryngeal nerve
Function of vocalis muscle? Attachments, actions and innervation?
Reduces tension on vocal cords during speech–> decreases pitch
From inner surface of thyroid–> anterior arytenoid
Inferior laryngeal
Where and what do the aryepiglottic folds do?
Triangular opening at the laryngeal entrance
Bound in front by the epiglottis and behind by the arytenoid cartilages, corniculate cartilages and interarytenoid notch
Involved in phonation
What is conductive hearing loss a problem with? Sensorineural hearing loss?
Sound travelling from the environment to the inner ear
The sensory system or vestibulocochlear nerve in the inner ear
Other things to consider with hearing loss?
Tinnitus, vertigo, pain, discharge, neurological symptoms
Where is the tuning fork placed in Weber’s test? What is a normal result? What about conductive or sensorineural hearing loss?
Middle of the forehead
Sound is heard equally in both ears
Conductive= louder on AFFECTED side
Sensorineural= louder on INTACT side
Where is the tuning fork placed in Rinne’s test? Normal result? Rinne’s also positive in what hearing loss? Negative in what?
On the mastoid process, ask when they can no longer hear the noise, hover it 1cm from the same ear- repeat on the other side
Rinne’s positive= air> bone conduction(sound heard again when bone conduction ceases and moved next to ear)
Sensorineural hearing loss
Conductive hearing loss
Causes of sensorineural hearing loss? Medications?
Sudden<72 hours
Presbycusis
Noise exposure
Meniere’s disease
Labyrinthitis
Acoustic neuroma
Neurological conditions
Infections
Loop diuretics, aminoglycoside antibiotics e.g. gentamicin, chemotherapy drugs