function of the larynx
to protect the airway from ingestion of food
we use it to make sound, phonation and speech - not its principle function
how is the larynx related to Parkinson’s
peoplee who die of parkinsons usually have asparated food and fluid and end up dying of pneumonia
summarise the implications of the sinuses (frontal and sphenoidal)
they make the head lighter
also clinically - can become infected
can the nasal cavity feed into teh cranial cavity
yes
describe the nasal cavity *
at the upper part of the resp tract - they permit airflow into airway
have turbinate bones, conchae are bones and the soft tissue - shelves of bone that project into the nasal cavity and are covered by resp epi. there are 3 pairs proijecting ionto nasal cavity - superior, inferior and middle.
spaces between conchae are meatuses. superior between superior adn middle conchae, middle between middle and inferior, inferior below inferior
what is the role of the conchae and meatuses *
warm and hufidify air so that cold air is not hitting lungs
immune func - trap pathogens (problem because nasal cavity drains into the cranial cavity)
drainage route for sinuses
idnetify the bones that contribute to the nasal cavity *
image
why can you only see the frontal and nasal sinuses in a saggital view *
the other sinuses are more lateral so are not seen in the midline
describe the arterial blood supply of the nasal cavity *
from branches of the internal carotid artery and external
very good blood supply
describe the innervation of the nasal cavity *
sensory innervation - trigeminal (V1 anterior region, V2 ppsterior region), olfactory (smell to the brain), facial (mucous mem of glands eg lacrimal glands),
sympathetic trunks from T1 (vascular sm)
describe the venous drainage of the nasal cavity *
superior parts of nasal cavity drain into the cranial cavity - link for infection
describe teh paranasal sinuses *
air filled
line anterior aspect of facial skeleton
function - reduce weight, provide crumple zone to protect brain, help with resonation ie project the voice
warm - so bacteria grow = infection
innervated by branches of the trigeminal nerve
identify the paranasal sinsues *
image
locate the sinues on an x ray
darker region
ethmoidal air cells rather than sinus - because sinus is single large cavity and ethmoid air cells are like honeycomb
illustrate the areas of sinus drainage *
in the meatuses
ethmoidal cells drain onto the ethmoidal bulla in the middle meatus
sphenoidal sinus drains into the spheno-ethmoidal recess
frontal sinus drain through the infundibulum opening of frontal nasal duct
maxillary sinus opens in the floor of the semilunar hiatus
where are tears drained
through the nasolacrimal duct into the back of the nassal cavity
why does head feel full off cold in the morning
fluid collects there over night because sinuses cant drain in that position
describe the larynx *
hollow
composed of cartilage, membrane and muscles
acts as a valve (most important function) and sound producer (structures that stop food going down airway can also vibrate = sound)
how do you increase volume of voice
project air over vocal cords at a faster rate
innervation of the vocal cords
recurrent laryngeal nerve - because of this nerves location problems with the larynx may indicate problems in the L lung which is near the L recurrent laryngeal - would cause a change in voice (hoarseness and cough)
nerve suseptible too damage by bronchial or oesophageal tumour/swollen mediastinal lymph nodes - and surgery in respnse to this
illustrate the laryngeal cartilages from a lateral view, and describe relations between the cricoid cartilage and thyroid cartilage *
small gap between thyroid cartilage and cricoid cartilage
thyroid cartilage rocks back and forwards on the larger posterior section of cricoid around the cricothyroid joint - partly how tension in vocal folds is altered - move anterior attachment and posterior attachment of the vocal folds further apart
describe the laryngeal cartilages from a posterior view
describe the arytenoid cartilages *
arytenoid cartilages swivel from side to side - elements of the vocal folds are attached to the anterior of these so when they swivel they open and close the airway
describe the anatomy of the vocal folds *
there are ligaments from posterior to anteroir
mucosal tissue draped over whole thing - folds out to form a vestibule, then folds back in over another ligament
describe the view of the vocal folds down the endoscope
hole betwene vocal chords is the rima glottidis - seen when airway is open
when phonation is taking place the vocal folds are aducted in order to vibrate
illstrate a closed airway *
image
describe the intrinsic muscles of the larynx *
change the tension in the vocal chords - open and clsoe airway for phonation
cricothyroid muscle (from cricoid to thyroid catilage) - when contract thyroid cartilage rocks forwards.this puts tension on vocal chords
lateral crico-arytenoid - contract andd spin the arytenoid cartilages inwards bringing the vocal folds closer together (aducting the vocal folds)
posterior crico-arytenoid, oblique arytenoid and transverse arytenoid - open up vocal folds and so the airway
vocalis muscle - reduces the tension in the folds by bringing the thyroid cartilage to the cricoid
thyro-arytenoid muscle - broad flat muscles, act asa sphincter for the vestibule by pushing soft tissues medial, they also narrow the inlet by pulling the arytenoid cartilage forward and epiglottis to the arytenoid cartilages - innervated by the recurrent laryngeal nerve
describe the nerve supply of the larynx *
vagus nerve has 2 branches - superior laryngeal nerve and recurrant laryngeal nerve
recurrent laryngeal - longer on the L than R because L loops around the ligamentum arteriosum near lung, R goes around R subclavian artery - travel with the inferior thyroid artey
superior laryngeal nerve branches into the internal laryngeal nerve and external laryngeal nerve - they travel with the superior thyroid artery
internal - sensation and muscles
external - smaller involvement (just rocks the thyroid cartilage)
describe the effects of lesions of the vagus nerve *
lesion before branching = complete paralysis
lesion of internal laryngeal = loss of sensation above vocal folds - problem because coughing wont be initiated (loss of protective mech)
of external = paralysis of cricothyroid
of recurrent = paralysis of all muscles of larynx except cricothyroid, and loss of sensation below the vocal folds
consequence of the vagus branches travelling with thyroid arteries
removal of thyroid can be associated with damage of these nerves
what are teh rpotectove mechanisms for the airway
swallowing - have to close airway and protect airway
gag reflex - stop things going down airway
sneezing and coughing - remove things irritating the airway
describe the differences between coughing and sneezing
relates to the soft palate
if raised to block of nasal cavity - air will come out of mouth = coughing - afferent innervation CN 10, efferent = CN10 and V3
if soft palate closed down = air directed posteriorly to the soft palate into nasal cavity = sneezing - afferent innervation V2, efferent = CN10
describe how you can intubate someonw
chin lift/jaw thrust so you can see the airway
either via the oropharynx or nasopharynx
endotracheal intubation/cicothyroidotomy/tracheostomy
locate features of the auditory apparatus
what is a possible consequence of an ear infection
infection of the mastoid air cells = damage to mastoid air cells = errode through bone into cranial cavity
routes of infection into the cranial cavity
from root of upper teeth into the maxillary sinus
from nasal cavity into frontal or sphenoid sinus
mastoid air cells to cranial cavity
venous drainage
describe what the facial nerve innervates
motor - muscles of facial expression, stapedius, digastric (posterior belly), stylohyoid
sensory - taste for ant 2/3 tongue, PNS (lacrimal glands, mucous glands of nasal cavity, hard and soft palates, sublingual and submandibular glands) and general sensation from the external acousitic meatus and deeper parts of the auricle
where on the brainstem does the facial nerve emerge from
the lateral surface between the pons and the medulla
describe the path of the facial nerve through the skull
through internal accoustic meatus to the stylomastoid foramen then through the parotid gland for the muscles of facial expression
smaller branch leave throigh teh petrotympanic fissure - join the lingual nerve and carry efferent fibres to submandibular and sublingual, bring back taste from anterior 2/3 tongue
what does the pharyngotympanic tube connect
the middle ear and the nasal cavity
what is the clinical relevance of the relationship between the sphenoid sinus and the pituitary gland
there is only a thin bone shelf between the sinus and the hypophysial fossa
also only a thin shelf between sinus and nasal cavity
the pit gland can be surgically approached through nasal cavity, passing through the anteroinferior aspect of the sphenoid bone - into the sphenoid sinus and then through the top of the bone into the hypophyseal fossa
describe the external ear
made of the auricle, external and auditory meatus - it collects sound and directs it ot tympanic membrane
auricle formed from fibrocartilage skeleton covered by adherent skin - has a lobule without fibrocartilage skeleton inferiorly and a tragus anteriorly that overlaps the opening of the external meatus. the meatus leaves from the concha of the auricle which is the hollow centre of teh auricle. It assists in capturing sound
medial 2/3 meatus are in the temporal bone
skin lining the external meatus contains ceruminous glands and outer part is hairy
innervated by the auriculo-temporal nerve anteriorly and the vagus nerve posteriorly
describe the middle ear
irregular air space in the temporal bone
tympanic cavity extends posteriorly into base of mastoid process as the tympanic antrum and anteriorly it communicates with the nasopharynx via the pharyngotympanic tube
the tympanic cavity is traversed by the chain of ossicles that transmits vibrations to inner ear through the oval window in the medial wall of the middle ear
describe the internal ear
lies in the petrous temporal bone medial to middle ear
has the cochlea, vestibule and 3 semicircular canals
describe the laryngeal surface anatomy
feel laryngeal prominance (thyroid cartilage) - palpate the notch, and the 2 laminae of the thyroid cartilage
follow anterior border of the cartilage down until you feel a depression due to cricothyroid membrane
then the concave anterior part of cricoid cartilage
below this you can feel the first 2 rings of teh trachea
the hyoid bone lies above the thyroid cartilage - palpate the body and 2 horns laterally
describe how you would explore the external auditory meatus and tympanic membrane using an otoscope
straighten ear by pulling pinna upwards and outwards (in paeds - down and back)
hold the otoscope like a pen and use little finger to hold at the cheek of pt to avoid trauma to the inner ear
rotate the otoscope
list the cartilages of the nose and the function*
they provide support for the nose, anterior and on each side of the nose
lateral processes of the septal cartilage
septal cartilage
superior margin of the septal cartilage
major alar cartilage
3/4 minor alar cartilages
describe how the laryngeal cartilages are involved in increasing the intra-thoracic pressure *
they close the rima glottidis
the arytenoid cartilages pull the vocal folds closer together - closing the airway = increase in intrathoracic pressure
teh arytenoid cartilages are moved by the lateral cricoarytenoid muscles
describe how the laryngeal cartilages are involved in phonation *
vocal cords adducted, they make sound by rubbing together - arytenoid cartilages swiveled
air is forced through the closed rima glottidis - cause vocal chords to rub against each other and produce sound
the tension in the vocal chords is adjusted by the vocalis and cricothyroid muscles
action of the laryngeal cartilages in the cough sneeze reflex *
there is sudden abduction of the vocal folds ie becasue the arytenoid ligaments have swiveled in the other direction - releasing intrathoracic pressure = sneezing
posterior cricothyroid muscles involved
what is the tympanic memrane *
it separates the external acoustic meatus from the middle ear
at an angle sloping medially from top to bottom, anteriorly to posteriorly
has a connective tissue core and lined with skin on the outside and mucous membrane on the inside
around the periphery is a fibrocartilaginous ring attaching it to the tympanic part of the temporal bone
describe the anatomy of the auditory ossicles *
bones of the middle ear, consisting of the malleus, incus and stapes
they form an osseous chain across the middle ear from the tympanic membrane to the oval window of the middle ear
malleus - head of malleus is rounded upper part (articulates with the incus), below this is teh constricted head of the malleus, below this are anterior and lateral proesses, below these is the handle of the malleus whhich attaches to the tympanic membrane
incus - body articulates with the malleus, long limb travels parallel to handle of malleus but bends and articulaees with stapes. short limb extends posteriorly and is attached by a ligament to upper posterio wall of middle ear
stapes - head articulates with the incus, anterior and posterior limb attach to the oval base, the base fits into the oval window on the labyrinth wall of the middle ear
describe the anatomy of the external acoustic meatus *
extends from the concha to the tympanic membrane (1 inch)
consits of cartilage and bone - lateral 1/3 from cartilaginous extensions from the auricle, medial 2/3 is a bony tunnel in the temporal bone
throughout its length it is covered in skin, some contains hair and modified sweat glands producing cerumen (ear wax)
doesnt follow a straight course
describe the anatomy of the pharyngotympanic tube *
connects the middle ear to the nasopharynx
equalises pressure on both sides of the membrane
opening on the middle ear is on the anterior wall and from here it extends forward, medially and downward to meet the nasopharynx
1/3 nearest middle ear is the bony part - clearly visible on inferior surface of the skull at the junction of the squamous and petrous part of the temporal bone, immediately posterior to the foramen ovale and foramen spinosum
cartilaginous part - remaining 2/3
what separates the upper and lower airway
the vocal chords
how do you stop the tongue blocking the oropharynx *
head tilt chin lift
jaw thrust - doenst move the neck, preferable if spinal chord injury
describe the relationship of the paranasal sinuses with the nasal cavity *
they develop as outgrowths from the nasal cavities and erode into the surrounding bones
all the sinues drain into the nasal cavity
what are the 4 paranasal air sinuses *
ethmoidal cells
sphenoidal sinus
maxillary sinus
frontal sinus
nerve supply of the frontal sinus *`
supra-orbital nerve from the opthalmic nerve (V1) which is a division of the trigeminal nerve
nerve supply of the ethmoidal cells *
the anterior and posterior ethmoidal branches of the nasocillary nerve from teh opthalmic nerve V1
the maxillary nerve V2 via orbital branches from the pterygopalatine ganglion
what is the nerve supply of the sphenoidal sinus *
posterior ethmoidal branch of the opthalmic nerve V1
maxillary nerve V2 via orbital branches from the pteryogopalatine ganglion
what are the membranes of the larynx and are the intrinsic or extrinsic *
thyrohyoid membrane - extrinsic
hyo-epiglottic ligament - extrinsic
cricotracheal ligament - extrinsic
fibro-elastic membrane - intrinsic
cricothyroid ligament (cricovocal membrane, cricothyroid membrane) - intrinsic
quadrangular membrane - intrinsic
describe the thyrohyoid membrane *`
spans between superior margin of thyroid cartilage and teh hyoid bone
it is attached to superior margin of thyroid laminae and adjacent anterior margins of the superior horns
ascends medial to the greater horns and posterior to body of hhyoid bone to attach to superior margin of these structures
posterior borders are thickened to form lateral tyrohyoid ligaments
also thickened anterior in the midline forming median thyrohyoid ligament
describe the hyo-epiglottic ligament *`
extend from body of epiglottis anterosuperiorly to body of teh hyoid bone
describe the cricotracheal ligament *`
runs from lower border of the cricoid cartilage to adjacent upper border of first tracheal cartilage
describe the fibroelastic membrane of the larynx *
links together with the laryngeal cartilages and completes architectural framework
composed of lower cricothyroid ligament and upper quadrangular membrane
describe the cricothyroid ligament *
attached to arch of cricoid cartilage
extends superiorly to end in a free margin which attaches to the thyroid cartilage and the vocal processes of the arytenoid cartilages
between these points the free margin is thickened to from the vocal ligament
anteriorly te cricothyroid ligament is thickened to form median cricothyroid ligament
describe the quadrangular membrane
*
runs between the lateral margin of the epiglottis and anterolateral margin of epiglottis on the same side
also attaches to corniculate cartilage
has a free upper and lower margin
free lower margin thickened to form vestibular ligament under the vestibular fold
what are the extrinsic muscles of the larynx *
the infrahyoid and suprahyoid muscles of the larynx
