Head and Neck review Flashcards
What is a fontanelle?
a large membranous, unossified gap that exists in the neonate and the newborn between the bones of the skull.
Anterior= where coronal and sagittal sutures will meet
Posterior= where sagittal and lambdoid sutures will meet
function of fontanelles?
allow movement of skull bone during birthing process so head can deform as it passes out through the birth canal, so moulding occurs
allow for post-natal growth
how is neonatal skull different from adult?
sutures between adjacent cranial bones open in newborn, closed in adult
2 frontal bones normally fuse, but occasionally persist in the adult (metopic suture)
Bony proportions different – facial skeleton small at birth
Alveolar processes and paranasal sinuses rudimentary at birth
When does the anterior fontanelle and posterior fontanelle close?
anterior- within 2 yrs
posterior- within 6-9mnths
Problem of small foetal mastoid process during childbirth?
forceps may damage facial nerve as will be relatively superficial so close to surface as it emerges from the stylomastoid foramina
what is the antrum in the facial skeleton?
maxillary sinus in body of maxilla
3 major divisions of trigeminal nerve before leaving middle cranial fossa?
opthalmic
maxillary
mandibular
where does the mandibular nerve exit the skull?
foramen ovale
why might a fracture of the mandible cause numbness of the lower lip?
damage to the inferior alveolar nerve, a branch of the mandibular nerve which is a branch of the trigeminal nerve, which hence causes a loss of function of the mental nerve which branches from the inferior alveolar nerve, passes through the mental formaina in the body of the mandible and innervates the oral mucosa of the inferior lip
What is the ligamentum nuchae?
It is a thickened fibroelastic tissue that attaches to the external occipital protuberance and the posterior border of the foramen magnum to the spinous processes of the cervical vertebrae.
What does the ligamentum nuchae help to do?
maintain normal curvature of cervical spine
why are cervical vertebrae prone to dislocation in whiplash injuries?
almost horizontal alignment of the articular facets between adjoining vertebrae.
problem of a posterior prolapse of IV disc between C2 and C3?
The prolapse may cause pressure on the spinal cord above the phrenic nerve outflow of C3, C4 and C5. If this happens suddenly, respiration will cease as phrenic nerve innervates the diaphragm which is necessary for inspiration (respons. for 70% of chest expansion in quiet respiration)
where does the middle meningeal artery enter the cranial cavity?
through foramen spinosum, and then lies just behind pterion
type of cranial fracture causing an epidural haematoma?
depressed fracture
what might a depressed fontanelle mean?
dehydration
what might a bulging fontanelle indicate?
increased intra-cranial pressure
where is the stylomastoid foramen located?
on lower surface of temporal bone, between the styloid and mastoid processes
how are the head and face positioned in congenital torticollis?
head tilts toward, and face turns away from, the affected side
how does the articular capsule of TMJ fit the mandibular fossa and articular tubercle?
upper surface of disc is concavo-convex (A-P)
why is an infection deep in the pterygoid region of danger to the eye?
pterygoid venous plexus located in the infratemporal fossa is connected with both the opthalmic and anterior facial veins, it drains into the cavernous sinus- receives blood from s and i opthalmic veins, so infection may cause a cavernous sinus thrombosis which can cause paralysis of extraocular muscles, or pus from infection may cause direct increased opthalmic venous pressure
what is the parotid duct and how can it be palapated?
route that saliva takes from parotid gland, into the mouth
when jaw clenched tight, it can be felt lying on the contracted masseter muscle
when does the parotid duct enter the mouth?
on piercing the buccinator muscle (CN XII), it opens into the mouth opposite the second upper molar tooth
function of occipitofrontalis
occipital belly: scalp retraction, increasing effectiveness of frontal belly, innervated by post auricular branch
frontal: protracts scalp, elevates eyebrows and wrinkles skin of forehead
function of orbicularis oculi
closes eyelids, palpebral part gently and orbital part tightly- winking
function of orbicularis oris
tonus closes oral fissure, phasic contraction compresses and protrudes lips (kissing) or resists distension (when blowing)
function of buccinator
presses cheek against molar teeth, works with tongue to keep food between occlusal surfaces and out of oral vestibule, resists distension (when blowing)
function of platysma
depresses mandible (against resistance), tenses skin of inferior neck and face- conveys stress and tension
causes of facial nerve palsy?
facial nerve palsy of newborn parotidectomy tumours or aneurysms inflammation near stylomastoid foramen e.g. due to viral infection fracture of temporal bone
difference between facial nerve palsy and bell’s palsy?
bell’s: unknown cause, tend to recover
facial: known cause, no recovery
how is facial nerve palsy differentiated from a stroke?*
forehead wrinkling spared in a stroke, but not in facial nerve palsy as bilateral innervation of facial nerve
what is a periorbital ecchymosis?
purplish/reddish discolouration of skin around orbit due to blood in SC tissue and skin that has been extravasated, can spread from scalp into eyes
where is the cavernous sinus located?
on the upper surface of the sphenoid bone
how do cavernous sinuses on each side communicate?
by intercavernous sinus
what does the cavernous sinus drain into?
the basilar and pterygoid venous plexuses via emissary veins
what is the pterygoid venous plexus?
situated between temporalis and lateral pterygoid muscles
receives venous drainage from venae comitantes of maxillary artery
anastomoses with facial vein via deep facial vein, cavernous sinus, and is drained by the maxillary vein
what branches does the facial nerve give rise to in the facial canal?
chorda tympani
greater petrosal nerve
nerve to stapedius
how is cauliflower ear produced?
trauma to external ear may cause a haematoma to form between the perichondrium and cartilage. Blood from perichondrium may then be unable to supply cartilage, so necrosis occurs as cartilage avascular, and subsequent fibrosis and deformity results.
why might a child with recurrent middle ear infections benefit from adenoidectomy?
adenoids probable blocking Eustachian tube, compromising equlibration of air pressures, causing -ve pressure in tympanic cavity with resultant air absorption and a concentrated mucus secretion predisposing to infection, and mucus secretion can be drained into nasopharynx if eustachian tube blockage removed
what causes shape of face to change when permanent teeth eruption and subsequent puberty?
growth of PN sinuses
why might otalgia be result of referred pain?
innervation of inner part of tympanic membrane in middle ear is via glossopharyngeal nerve, which also innervates the oropharynx, so something like tonsillitis of pharyngitis may present as otalgia
difference in presentation between an upper and a lower motor nerve palsy of the facial nerve?*
upper= forehead sparing, so can still wrinkle skin of forehead on affected side lower= no forehead sparing as lesion after bilateral innervation, so no innervation to occipitofrontalis
innervation of parotid gland?
glossopharyngeal nerve- synapses in otic ganglion
nerve which branches in parotid gland to give 5 terminal extracranial branches, and names of these branches?
facial nerve temporal zygomatic buccal marginal mandibular cervical
To Zanzibar By Motor Car
how would a patient with left hypoglossal nerve palsy present?
when asked to protrude tongue, it would deviate towards the left side
tongue would also show furrows on left side (grooves)
tongue would atrophy on L side in long term
which branch of the superior laryngeal nerve supplies the cricothyroid muscle?
external laryngeal nerve
function of cricothyroid?
It tenses vocal cords, increasing pitch. It also controls expiration of air in phonation.
what might happen if paralysis of cricothyroid?
difficult maintaining patent airways in breathing and swallowing as muscle
with which nerve do the glossopharyngeal post-ganglionic PNS fibres reach the parotid gland?
auriculotemporal from mandibular division of trigeminal
why might horner’s syndrome be associated with an arterial problem?
sympathetic nerve fibres hitch hike onto arteries of head and neck to supply their target structures:
from S cervical ganglion via ICA and ECA
from middle via I.thyroid
from inferior via vertebral
innervation loss to dilator pupillae and superior tarsal- ptosis and miosis of horners, and vasomotor function loss causes anhydrosis
how is the hyoid helped to be suspended by the pre-tracheal layer of deep cervical fascia?
fascia thickens superiorly to hyoid, forming a trochlea through which intermediate tendon of digastric passes (suprahyoid muscle)
where is the parapharyngeal space?
lateral to pharynx, close to carotid sheath structures, up to level of mediastinum. Tonsillitis may cause quinsy- peritonsillar abscess, or can enter space and spread into chest. May be drooling, won’t want to open mouth.
muscle comprising epicranial group of facial muscles?
occipitofrontalis
orbital group of facial muscles?
orbicularis oculi
corrugator supercilii- eyebrows drawn inferiorly and medially as concerned or worried
function of procerus and transverse part of nasalis?
Wrinkling skin over dorsum of nose-shows
Disdain or dislike
Flares nostril
dilators of mouth?
risorius, levator labii superioris, depressor labii inferioris
consequence of non-functioning orbicularis oris?
can’t close mouth, so uncontrollable drooling
smiling muscles?
levator anguli oris
zygomaticus major
saddness muscles?
depressor anguli oris
zygomaticus minor
undifferentiated tissues of what origin forms fascia?
mesenchyme
why is it useful to view neck as territories of triangles?
describe lumps in neck, provide clues as to where they have arisen from, as organised layout of neck anatomical structures
define muscular torticollis
dominant contraction of 1 SCM
how can a subdural haematoma be aspirated from a small baby?
use anterior fontanelle- larger, closes later
sensory innervation of neck?
cutaneous branches of cervical nerves from cervical plexus, extend upwards onto face- parotid region, area overlying angle of mandible
what is the neurocranium?
bony case of brain and cranial meninges, comprises calvaria and cranial base
what is the viscerocranium?
facial skeleton
b.supply to viscercranium?
ECA
blood supply to neurocranium?
ICA?
middle meningeal artery
if facial artery lacerated on 1 side of face, why is it necessary to compress both arteries to stop bleeding?
Because the artery has many anastomoses with other arteries of the face
major route of spread of infection from neck into thorax?
retropharyngeal space
contents of submandibular triangle of neck?
SM gland, LNs, hypoglossal and mylohyoid nerve, parts of facial artery and vein
contents of submental triangle of neck?
SM LNs, small veins which unite to form AJV
contents of carotid triangle?
Carotid sheath o Common carotid artery o Internal jugular vein o Vagus nerve o Deep Cervical Lymph Nodes Thyroid gland Larynx Pharynx External carotid artery and some of its branches Hypoglossal and Spinal accessory nerves Branches of cervical plexus
contents of muscular triangle of neck?
sternohyoid and sternothyroid infrahyoid muscles
thyroid and PT glands
what anstomosis supplies blood to brain and what is it formed by?
circle of Willis
R and L vertebral arteries from subclavian arteries, and ICA
which is the strongest cervical vertebra and why?
C2
as C1 carrying the skull rotates on it
infrahyoid muscle function?
depression hyoid and larynx in swallowing and speaking
work with suprahyoid to steady hyoid and so provide a firm base for tongue
4 infrahyoid muscles?
omohyoid
sternothyroid
thyrohyoid
sternohyoid
4 suprahyoid muscles?
digastric
mylohyoid
stylohyoid
geniohyoid
contents of large occipital triangle of posterior triangle?
accessory nerve, BP trunks, part of EJV, post branches of cervical plexus, cervical LNs, cervicodorsal trunk
contents of omoclavicular triangle of post triangle?
3rd part of SC artery, part of SC vein, suprascapular artery, supraclavicular LNs
borders of carotid triangle?
superiorly: P belly of digastric
medially: S belly of omohyoid
laterally: A border of SCM
overall function of hyoid muscles?
steady/move hyoid and larynx
scalp blood supply?
ECA: p auricular, occipital, superficial temporal
ICA: opthalmic- supra-orbital and supratrochlear
why would loss of scalp b supply not damage skull?
skull supplied by middle meningeal artery
why would involvement of epicranial aponeurosis in scalp laceration cause more profuse bleeding?
2 bellies of occipitofrontalis pull on aponeurosis in opp. directions to produce deeper cut
why might a parathyroid adenoma occur in the chest?
parathyroid tissue can be moved down with the thymus gland as the 3rd pharyngeal pouch gives rise to the PT glands and the thymus
why does the TMJ rarely dislocate posteriorly?
strengthened poster. by postglenoid tubercle poster. and intrinsic lateral ligament= extracapsular ligament
sphenomandibular ligament funtion? (from spine of sphenoid bone to mandible)
prevent inferior dislocation of TMJ
nerves that may be damaged in TMJ dislocation?
facial nerve
auriculotemporal nerve- from mand division of trigeminal, and carries post-gangl fibres of glossopharyngeal nerve to parotid gland from otic ganglion
where are the structures innervated by the opthalmic branch of trigeminal nerve derived from?
frontonasal prominence
where are the structures innervated by the maxillary branch of trigeminal nerve derived from?
maxillary prominence of 1st pharyngeal arch
where are the structures innervated by the sensory part of mandibular branch of trigeminal nerve derived from?
mandibular prominence of 1st pharyngeal arch
describe the course of the vagus nerve
arises from medulla, leaves by jugular foramen to run within carotid sheath to root of neck, then joins oesophageal plexus to enter into abdomen
describe course of accessory nerve
Arises from spinal cord, passes into cranial cavity via foramen magnum, then exits again via jugular foramen- IJV begins here as continuation of sigmoid sinus
which nerve innervates the middle ear?
tympanic branch of glossopharyngeal
complications of otitis media?
glue ear
mastoiditis
rupture of tympanic membrane
what is glue ear?
Glue ear is chronic otitis media with effusion
Negative ear pressure develops
Treated by drainage or grommets in membrane
4 components of pharyngeal arches?
cranial nerve
aortic arch
cartilage
mesenchyme
where does pharynx extend?
from base of skull to lower border of cricoid cartilage- derivative of 4th pharyngeal arch
what is a pharyngeal arch?
mesenchymal proliferations which form in lateral walls of embryonic pharynx
what is the facial skeleton derived from?
FN prominence and the 1st pharyngeal arch- maxillary and mandibular prominences
muscles of 4th pharyngeal arch?
cricothyroid
levator palatini
constrictors of pharynx
difference in composition between outer 1/3 and inner 2/3 of EAM derived from the 1st pharyngeal cleft?
outer 1/3= elastic cartilage
inner 2/3= tympanic plate of temporal bone
what is EAM lined throughout?
skin= stratified squam keratinized epithelium
composition of tympanic membrane?
outer part= strat squam keratiniz=sking
middle part= fibrous CT
inner part= low columnar epithelium continuation of middle ear cavity epithelium
what guards the EAM?
tragus
what may be the cause of sympathetic nerve damage causing ptosis?
blood vessel abnormalities e.g. aneurysm or atheroma as S nerve travel with arteries
Pancoast’s tumour- apical lung tumour
what side of fundus is blind spot found in normal eye?
medial (nasal) side
causes of a subdural haematoma?
Due to: - Torn cerebral veins
-Hypertension
- Trauma
These are particularly seen in the young and elderly as they are more likely to have cerebral atrophy/ underdeveloped cerebrum and therefore increased stress on cerebral veins. Also more likely in alcoholics (thrombocytopaenia) and patients with dementia.
what do the valveless dural venous sinuses mainly drain into?
IJV
oview of scalp venous drainage?
Superficial veins- occipital, P auricular and S.temporal which accompany the arteries supplying the scalp and drain into EJV
Supraorbital & Supratrochlear unite at the medial angle of the eye forming the Angular Vein, which drains into the Facial Vein and then into the IJV
S temporal and maxillary form retromandibular in parotid, which joints with P auricular to drain into EJV
oview of face venous drainage?
facial vein runs into IJV
Supraorbital and supratrochlear veins join to form the angular vein at the medial angle of the eye. The angular vein then drains into the facial vein
Superior and inferior labial veins drain into the facial vein
The facial vein is important because it receives venous drainage from the above veins draining the rest of the face.
It then travels down and joins the anterior branch of the retromandibular vein to form the common facial vein, which drains into the IJV
how does the retromandibular vein drain?
anterior branch joins facial vein to form common facial vein draining into IJV
posterior branch drains into EJV
occipital vein drainage?
sometime joins P auricular to drain into EJV
sometimes drains into IJV
why can thrombophlebitis of facial veins spread into interior of cranial cavity?
facial veins are valveless so despite normal drainage downwards into IJV, their connection with the cavernous sinus in upper portion of sphenoid bone via the superior opthalmic vein can allow a thrombus to pass into the sinus
why might blindness occur with opthalmic nerve lesion?
nerve provides sensory innervation to cornea so without this, the corneal reflex where protective blinking occurs won’t happen, so cornea vulneravle to forein particles that can cause ulceration, and scarring- which can lead to blindness.
blood supply to area of skin of forehead above eye?
supraorbital and supratrochlear arteries from opthalmic from ICA
S.temporal from ECA
why does blood and fluid collecting in the dense CT layer of the scalp- where b vessels located, not track into the subtemporal or occipital regions of skull but passes forward into orbital region?
subtemporal: as epicranial AN is continuous with temporal fascia which is attached to the zygomatic arch
occipital: as occipitalis attached to occipital bone and mastoid process
so therefore tracks into orbital region as frontalis inserts into skin, and SC tissue, and doesn’t attach to bone
why might a persistent lump of wax cause an unexplained cough?
vagus nerve: innervates EAM and middle ear via auricular branch, and is responsible for cough reflex (recrurrent laryngeal nerves from vagus innervate intrinsic laryngeal muscles which adduct VCs to close glottis)
how is glue ear caused?
Eustachian tube dysfunction: middle ear pressure unable to equalise with atmos pressure so -ve middle ear pressure occurs as resp epithelial cells absorb O2, fluid accumulates forming a sticky exudate where pathogens can grow which is unable to drain, so predisposes to ear infection
TM becomes adherent to ossicles so hearing defecit
referred pain in head and neck?
from cervical muscles- myofascial pain from cervical joints cardiac referred ear referred pain to TMJ referred pain to ear from pharyngitis- glossopharyngeal nerve, teeth, oesophagus
how can an infection of the middle ear cause mastoiditis and how can this subsequently spread?
mastoid air cells located posterior to middle ear cavity so infection can spread via intercommunciating air cells to lead to mastoiditis, producing and red and swollen area in the mastoid region behind the ear. This infection can then spread through the superior wall of the mastoid and into the cranial cavity, where meninges involvement causes meningitis, If the temporal lobe is involved, a brain abscess can result. Spread through the posterior wall can lead to a thrombosis in the sigmoid dural venous sinus that is continued as the IJV at the jugular foramen.
3 cell types of nasal mucosa?
pseudostratified ciliated columnar cells
goblet cells
basal cells
how can copious nasal discharges be produced?
inflammation of nasal cavity mucosa:
increased tissue fluid leakage=extravasation. In the nose,
extravasation of tissue fluids is also accompanied by increased mucous secretion
why do headaches and facial pain result from inflamed nasal mucosa?
Blocked nasal passages; discharge of secretions from
the PN sinuses interrupted- congested sinus= opacity on CT; stuffy feeling; irritation of
the mucosa;
Nerves supplying the nasal cavity & sinuses also supply
intracranial structures (the meninges, in patricular)
why could pressing a boil on the cheek lead to abducens nerve palsy?
There would be an increased risk of introducing pathogens from the boil into the cavernous sinus through venous channels of the
face that are devoid of valves. This could then lead to
cavernous sinus thrombosis Cranial nerves III, IV, V and VI are close relations of the cavernous sinus and could thus be damaged if there is thrombosis in their
vicinity of proximity to the cavernous sinus
how is the hypoglossal nerve related to the carotid artery?
passes between ICA and IJV lying on carotid sheath
how might a goitre affect blood vessel appearance in the neck?
superficial venous distension
most suitable explanation for mass in neck assoc with pain?
acute infection
what may cause a mass in the neck that changes with size as the patient eats?
a blocked salivary gland duct
worry of lateral masses in neck compared to midline?
frequently neoplastic
common cause of tension headaches?
neck stiffness= usually caused by spasm of cervical muscles
what do optic placodes give rise to?
lens
what is the retina derived from?
diencephalon- part of forebrain
how is growth of facial prominences stimulated?
neural crest cell migration which populate pharyngeal arches
where do external ears initially develop?
neck
how do ears come to lie in line with eyes?
growth of mandible- this also allows tongue to drop which allows palatal shelves from max prominences to grow towards each other and fuse in midline, giving us the secondary palate
why might a carotid artery dissection cause ptosis?
can damage sympathetic fibres from superior cervical ganglion which hitch hike onto the artery, and innervate the superior tarsal muscle responsible for elevating the upper eyelid alongside the LPS muscle innervate parasympathetically by the oculomotor nerve
result of damage to chorda tympani nerve?
reduced salivation
loss of taste on ipsilateral anterior 2/3 of tongue
result of damage to nerve to stapedius?
ipsilateral hyperacusis
result of damage to greater petrosal nerve?
ipsilateral reduced lacrimal fluid production
what function of facial nerve affected if extracranial lesion?
only motor as all PNS and sensory functions prior to nerve’s exit from cranium via SM foramen
why might a blow to the eyeball result in blood in maxillary sinus?
displacement of orbital contents in blowout fracture. inferior border of orbit is thin so can break resulting in blood in maxillary sinus
how does a lateral cleft lip occur?
failure of fusion of medial nasal prominence and maxillary prominence on that side
why might a TMJ dislocation compromise the parotid gland?
can damage auriculotemporal nerve which carries post-gangl fibres of glossopharyngeal nerve from otic ganglion to innervate the parotid gland
main primary targets of postganglionic sympathetic fibres innervating head and neck?
blood vessels
why might flushing occur with horner’s syndrome?
dilation of blood vessels on affected side due to loss of sympathetically mediated vasoconstriction
name given to the slow reduction in focusing capacity
in old age where lens becomes harder and more flattened?
presbyopia
what is mydriasis associated with?
sympathomimetic agents
glaucoma
dilating drops
when is miosis seen?
damage to sympathetic trunks
parasympathomimetic drugs
inflammation of iris
drug tment of glaucoma
sensation in eye of conjunctivitis?
gritty
why might eye appear bloodshit?
trauma
increased pressure in eye
infection
allergy
why might cavernous sinus thrombosis cause extraocular muscle damage?
nerves innervating muscles pass through sinus and located within lateral wall of sinus
most common cause of intracranial facial nerve damage?
middle ear infection, due to close proximity of facial nerve within facial canal
bulging of babies head after birth due to ventouse delivery, why??
positioning of suction cup relative to anterior and posterior fontanelles *
how is the epitympanic recess connected to the mastoid air cells?
recess opens into the mastoid antrum (space) via the aditus, and antrum communicates with mastoid air cells (via intercommunicating air cells?*), so this allows spread of middle ear infection e.g. due to S.pneumoniae or H.influenzae to cause mastoiditis- can then cause meningitis, brain abscess or sigmoid venous sinus thrombosis
what is an acoustic neuroma and what does it result in?
benign tumour which grows on the vestibulocochlear nerve so is a cause of neural hearing defecit
innervation to carotid body and carotid sinus?
sinus branch of glossopharyngeal nerve
so this allows sensory transmission to medulla oblongata, then can mediate vagal input to the heart?
how does the ICA enter the skull?
via the carotid canal in the temporal bone which then allows entry into middle cranial fossa
what arteries does the thyrocervical trunk give rise to?
ascending cervical
transverse cervical, both supplying neck
inferior thyroid- supplying inferior pole of thyroid
suprascapular- supplying shoulder
primary lymphoid organs?
bone marrow- haemopoiesis
thymus- T cells mature. thymus originates from ventral part of 3rd pharyngeal pouch.
secondary lymphoid organs?
tonsils
adenoids
spleen
MALT
where does the thoracic duct arise?
cisterna chyli on RIGHT
but drains into left SCV
what is intestinal lymph known as?
chyle
at what vertebral level does thoracic duct arise?
L2
at what vertebral level does thoracic duct cross midline?
T5
what does the R lymphatic duct drain?
R side of H and N
right arm
right side of upper trunk
components of lymph node and their location?
cortex: B cells
paracortex: T cells
medulla: macrophages, large blood vessels, medullary cords and sinuses
where are the anterior and posterior chains of superficial cervical LNs located?
along EJV
drainage of what structures is by the submental LNs of the regional group?
base of tongue
lower lip
chin
floor of mouth
drainage of what strucutres is by the submandibular LNs?
cheeks
gums
side of nose
upper lip
drainage of what structures is by pre auricular LNs?
lateral part of face/scalp
eyelids
ear
shape of orbit?
pyramid
difference between open and closed angle glaucoma?
how does glaucoma affect vision?
elevated IOP associated with increased risk of disease but not disease itself, disease= optic neuropathy- loss of optic nerve fibres, raised pressure may damage optic nerve
open= open angle between iris and cornea, but an increased resistance to aqueous outflow within the trabecular meshwork so causing a rise in IOP
closed= problem between iris and cornea so fluid can’t get to meshwork where reabsorption occurs as iris closes drainage angle
what are the surfaces of the middle ear?
anterior wall= carotid wall-ICA
posterior wall= mastoid wall- mastoid air cells
medial wall= outer plate of oval window
lateral wall= inner plate of tympanic membrane= low resp. columnar epithelium
roof= tegmen tympanum
floor= jugular wall- IJV runs underneath
when might a patient have difficulty swallowing both solids and liquids?
would this disease affect their ability to wrinkle the forehead and state why
stroke
no, as occipitofrontalis would still be intact due to bilateral innervation of the facial nerve as a stoke is an upper motor neuron lesion so only damages one of the 2 facial nerves and occipitofrontalis receives nerve fibres from both facial nerves. Facial nerves cross to supply opposite side of occipitofrontalis to part of brain they originate from but fibres from both nerves are given off to supply occiptiofrontalis so if one nerve is damaged before the bilateral innervation, the muscle still receives innervation from the other nerve whereas a lower motor lesion occurs after the bilateral innervation, damaging fibres from both nerves supplying muscle on affected side so muscle doesn’t function
blood supply to tympanic membrane?
maxillary artery branches
innervation to the philtrum and why?
opthalmic division of trigeminal
dervived from FNP
derivatives of reichert’s cartilage?
stapes
stylohyoid ligament
lesser cornu and part of body of hyoid
styloid process of temporal bone
nerves which may be damaged when performing a carotid arteriogram puncture?
sympathetic trunks- lie just outside carotid sheath on pre-vertebral fascia glossopharyngeal vagus accessory hypoglossal
thyroid gland originates where, and what is this site called?
base of tongue
foramen cecum
marked by an indentation on dorsum of tongue in adult
how could you determine if functioning thyroid tissue was responsible for a lump in the neck?
give radioactive iodine= radioisotope scanning, and then image the neck to see whether the iodine was taken up by the lump, if it was then functioning thyroid tissue is present
most likely cause of a patient’s hoarse voice following a thyroidectomy, and if laryngoscopy reveals left VC palsy?
damage to left recurrent laryngeal nerve on ligation of the inferior thyroid artery
how is the gag reflex elicited?
touching the soft palate with a non-food substance
via what structure does the L supraclavicular LN receive lymph drainage from most of the body?
the thoracic duct
originates at cisterna chyli
crosses over to L side of body at transverse thoracic plane which runs through IV disc between T4 and T5
which LN would you expect to be enlarged in tonsillitis?
jugulo-digastric located just below angle of mandible
what is a pharyngeal pouch and why might it occur?
a diverticulum of the pharyngeal mucosa through a weakening between cricopharyngeus and thyropharyngeus muscles forming upper oesophageal sphincter. pressure due to swallowing can cause an out-pouching through this weakness. 1 cause may be incoordination of swallowing reflex meaning more pressure builds up in upper oesophageal sphincter causing a diverticulum to form
why may the laynx appear as dense as bone on a radiograph?
larynx may ossify with age so imaging should be carried out in more than 1 plane in these cases
name 3 common causative organisms of otitis externa?
staph aureus
pseudomonas aeruginosa
aspergillus= mould= multicellular fungi, may cause aspergillosis in lungs of patient with CGD
2 management strategies for glue ear?
grommets
drainage
what might sinusitis of sphenoidal sinus cause if it spreads?
cavernous sinus thrombosis
what does glossopharyngeal nerve innervate?
motor: stylopharyngeus
general sensory: oropharynx, laryngopharynx, inner part of TM, middle ear, carotid body and sinus via sinus nerve branch
specific sensory: posterior 1/3 of tongue
PNS: parotid gland via auriculotemporal from mandibular division of trigeminal
expand on BAIL? hint: branches of mandibular division of trigeminal
buccal
auriculotemporal
inferior alveolar, which gives mental
lignual- chorda tympani travels with
how do fibres of glossopharyngeal reach otic ganglion?
via lesser petrosal nerve
how do sympathetics reach parotid gland?
travel from superior cervical ganglion to parotid along middle meningeal artery from maxillary from ECA
where are nerve fibres sent to from superior cervical ganglion?
upper 4 cervical nerves cardiac plexus dilator pupillae superior tarsal muscle nasal glands salivatory glands
where are nerve fibres sent to from middle cervical ganglion?
5th and 6th cervical nerves
cardiac plexus
lower larynx, trachea, laryngopharynx and oesophagus
where are nerve fibres sent to from inferior cervical ganglion?
7th and 8th cervical nerves
cardiac plexus
subclavian and vertebral arteries
give 2 reasons why excess lacrimal fluid may form?
corneal drying e.g. result of absent corneal reflex due to orbicularis oculi parlaysis
lacrimal drainage appartatus obstructed
3 components of middle vascular layer of eye?
choroid- red of eye, located between sclera and retina
ciliary body- connects choroid with iris, attaches and focuses lens via suspensory ligaments
iris- central aperture=pupil, and lies on anterior surface of lens, supplied by SNS and PNS
what is the fundus of the eyeball?
the interior part
why does light entering 1 eye cause both pupils to constrict?
as each retina sends fibres into optic tracts of both sides
define papilloedema
optic disc swelling viewed during opthalmoscopy due to increase CSF pressure which slows venous return from retina. pressure increase in extension of sub-arachnoid space around optic nerve
how might a small retinal vein from the central vein of the retina become blocked?
thrombophlebitis of cavernous sinus as central vein of retina enters cavernous sinus so a thrombus within sinus can pass into vein, with subsequent occlusion causing a slow and painless loss of vision
what forms roof of nasal cavities?
frontal bone
cribiform plate of ethmoid bone
sphenoid bone
how can sinusitis occur?
infection spread from nasal cavities through apertures that sinuses open through into cavities, producing inflammation and swelling of nasal mucosa
what forms floor of nasal cavities?
palatine processes of maxilla
horizontal plates of palatine bone
how can bell’s palsy be treated?
prednisolone- anti-inflammatory
aciclovir- varicella-zoster infection causing inflammation of nerve in facial canal
define rhinorrhea
runny nose
nasal cavity= well vascularised and glands present
main sensory innervation of laryngopharynx?
vagus nerve
describe the mechanism of swallowing
3 phases
1: voluntary- bolus of food moved into oropharynx from oral cavity
2: pharyngeal- pressure receptors in soft palatae and anter pharynx activated, afferent feedback to swallowing centre in medulla and efferent response via vagus nerve so VCs adducted to inhibit resp, hyoid bone and larynx raised by suprahyoid muscles and tongue, soft palate elevates to close off nasopharynx and superior constrictor contracts, epiglottis closes off larynx. middle and inferior constrictors innervated by superior laryngeal nerve aid movement into laryngopharynx. cricopharyngeus relaxes so UOS opened.
3: oesophageal- upper 1/3 striated so conscious control, rapid peristaltic wave to LOS.
what supplies blood to parotid gland?
transverse facial artery from s.temporal artery, and p.auricular artery, both from ECA
sensory innervation to partoid?
mandibular division of trigeminal
how does the bony labyrinth communicate with the subarachnoid space?
via the cochlear aqueduct
which nerves convey general sensation of tongue?
lingual from mandibular division of trigeminal and glossopharyngeal
4 functions of fascia in neck?
allow ease of movement both externally and internally e.g. in swallowing
determines spread of infection
creates natural cleavage planes for surgery
compartmentalises
what does the inferior thyroid vein drain into?
left brachiocephalic vein
S and M drain into IJV
where do regional and terminal LNs drain and what relation do these have to blood vessels?
regional drain into terminal lymph nodes (deep cervical)
these then drain into R short lymphatic duct and thoracic duct
regional related to EJV
deep related to IJV
complications of CSF rhinorrhoea?
meningitis
pneumocephalus- air in cranial cavity
which muscles elevate mandible?
temporalis, masseter, medial pterygoid
muscles depress mandible?
mainly gravity, lateral pterygoid, supra and infrahyoids
muscle protrude mandible?
lateral and medial pterygoid, massetter
muscles retrude mandible?
temporalis and masseter
muscles creating lateral movements of mandible?
temporalis same side, pterygoids opp side, masseter
