Week 1 Flashcards
what is mesenchyme?
- mesenchyme is embryonic connective tissue.
- it has the same properties as a connective tissue and develops into bone, cartilage, blood vessels etc.
what is the embryological origin of the neck?
branchial/pharyngeal arches
what is the embryological origin of the face?
develops from 5 mesenchymal processes/prominences.
what is the embryological origin of the skull?
develops from the mesenchyme in the head region of developing embryo.
how is the neural tube formed and what does it give rise to?
- some of the ectoderm in the midline of an embryo folds down o form neural tube > brain + spinal cord.
what is the role of somites in the future head region of an embryo?
they help in cranial skeleton development.
what are pharyngeal/branchial arches?
series of arches which develop around the future mouth and pharynx.
how many branchial arches develop in humans?
5
- 6 arches start to develop but number 5 disappears so we are left with 1,2,3,4 and 6.
when do branchial arches begin developing?
late week 4 of gestation
what embryological tissues make up branchial arches? give detail
- ectoderm lines the outside > also forms clefts in between the arches.
- mesoderm in the middle (+ neural crest cells) > cartilage, muscles.
- endoderm on the inside > also forms pouches between arches.
which nerve is derived from the 1st branchial arch?
mandibular branch of trigeminal nerve (V).
what nerve is derived from the 2nd branchial arch?
facial nerve (VII).
which nerve is derived from the 3rd branchial arch?
glossopharyngeal nerve (IX).
which nerve is derived from the 4th branchial arch?
superior laryngeal branch of vagus (X).
which nerve is derived from the 6th branchial arch (no 5th arch)?
recurrent laryngeal branch of vagus (X).
which nerve innervates the muscles of the face?
facial nerve (VII).
which branchial arch are the facial muscles derived from?
2nd branchial arch
- remember because facial nerve is derived from this arch and this nerve innervated the facial muscles.
the anterior belly of the digastric muscle is innervated by which nerve?
- mandibular division of trigeminar nerve (V3).
the posterior belly of the digastric muscle is innervated by which nerve?
- facial nerve (VII).
the anterior belly of the digastric muscle is derived from which branchial arch?
1st
the posterior belly of the digastric muscle is derived from which branchial arch?
2nd
label this
The Meckel’s cartilage, Malleus and Incus are derived from which branchial arch?
1st
The Stapes, Styloid process, Stylohyoid ligament and Lesser horn of hyoid bone are derived from which branchial arch?
2nd
The greater horn and body of the hyoid bone are derived fromk which branchial arch?
3rd
The thyroid cartilage is derived from which branchial arch?
4th
The cricoid cartilage is derived from which branchial arch?
6th
which other important structures develop from the branchial arches?
tongue
thyroid gland
parathyroid gland
part of the pituitary gland
list the 5 processes/prominences which the fave develops from?
- one frontonasal process (from mesenchyme superior to future mouth).
- two maxillary processes (from maxillary part of 1st branchial arch mesoderm).
- two mandibular processes (also 1st arch mesoderm).
how is the philtrum formed?
when the medial nasal process further grows down downwards and laterally to form a philtrum.
label this
describe the development of the palate
what causes a cleft lip/palate?
when the palatine shelves fail to meet in the midline to form the secondary palate.
describe the bones composing the cranial vault
flat, membranous bones formed by membranous ossification calvaria.
describe the bones composing the base of the skull
irregular bones formed by endochondrial ossification.
how are the viscerocranuim > bones forming skeleton of face, formed?
partly from branches, and partly from sensory (special sense) capsules.
at which age does the anterior fontanelle close?
1.5 years old
why is the skull/cranial vault not fully formed at birth?
- sutures between them soft > allow deformation during passage through birth canal.
what is craniosynostosis?
Craniosynostosis is a birth defect in which the bones in a baby’s skull join together too early. This happens before the baby’s brain is fully formed. As the baby’s brain grows, the skull can become more misshapen.
what are sensory capsules and what is their function?
- derived from mesoderm of somites in head and neck region.
- preform in cartilage and ossify to form bones around the sense organs i.e. nose, eye and ear.
- they form partly base of skull and partly viscerocranium.
what is treacher collins syndrome caused by?
1st pharyngeal/branchial arch abnormality.
how is an auricular/pinna haematoma managed?
- incision and drainage.
- pressure dressing.
- antibiotics.
what is a complication of auricular haematoma?
‘cauliflower ear’
what is the definition of otitis externa?
inflammation of external auditory meatus.
what is the management of otitis externa?
- antibiotic/steroid ear drops.
- +/- suction under microscope.
how can otitis externa be prevented?
no water or cotton buds in the ear
what is the definition of ‘malignant’ otitis externa?
- osteomyelitis of temporal bone.
what are the most common causative organisms in otitis externa?
- pseudomonas
- staphylococcus aureus
what is the usual presentation of ‘malignant’ otitis externa?
- elderly diabetic patient.
- severe pain.
- granulations in external auditory meatus.
- +/- cranial nerve palsies.
what is the management of ‘malignant’ otitis externa?
antibiotics for weeks or months
what is ‘glue ear’/otitis media with effusion?
Otitis media with effusion (OME) is a condition in which there is fluid in the middle ear but no signs of acute infection.
- sterile fluid.
what is the management of otitis media with effusion ‘glue ear’?
- observation for 3 months.
- otovent.
- Grommets are tiny tubes inserted into the eardrum. They allow air to pass through the eardrum, keeping the air pressure on either side equal.
what is the definition of acute supparitive otitis media?
pus in middle ear
presentation of acute suppurative otitis media?
otalgia +/- otorrhoea (pus coming out of ear due to perforation of eardrum).
management of acute supparitive otitis media
observation
paracetamol/ibuprofen
+/- antibiotics
what is the definition of tympanosclerosis?
calcification in tympanic membrane +/- middle ear.
what is the presentation of chronic suppurative otitis media?
- persistent purulent drainage through the perforated tympanic membrane.
or - A cholesteatoma is an abnormal collection of skin cells deep inside your ear. > skin in middle ear +/- mastoid bone.
what are complication of chronic suppurative otitis media?
‘dead ear’
facial palsy
meningitis
brain abscess
what is the management of a perforated tympanic membrane?
water precautions
+/- myringoplasty
what is the presentation of cholesteatoma?
- persistent offensive otorrohoea.
- headache.
- otalgia.
what is the management of cholesteatoma?
mastoidectomy
what is the definition of otosclerosis?
- abnormal bone growth occurs around the stapes bone in the middle ear, impeding its function as a piston onto the cochlea.
- this can result in progressive conductive hearing loss.
aetiology of otosclerosis?
- autosomal dominant condition, significant family history of disease.
management of otosclerosis?
hearing aid
stapedectomy
what are the differential diagnoses when presented with a facial nerve palsy?
- intratemporal e.g. cholesteatoma.
- extratemporal e.g. parotid tumour.
- idiopathic = Bell’s palsy.
what is the management of a facial nerve palsy?
- treat underlying cause (if possible).
- steroids.
- eye care.
what is the function of the middle ear?
- transforms acoustic energy from the medium of air to the medium of fluid.
- to do this it acts as a sound amplifier.
physiology of hearing
- sound waves > vibration of tympanic membrane.
- movement of ossicles > transmit vibration to oval window.
- waves travel through fluid of the cochlea > basilar membrane moves.
- movement of hair cells and their stereocilia on organ of Corti > opening of ion channels, release of neurotransmitters.
- propagation of signal to vestibulocochlear nerve > carries info to brain to be analysed and percievesd.
Describe the function of Weber and Rinne tuning fork tests
- Weber- a test of lateralisation.
- Rinne- a test that compares loudness of percieved air conduction to bone conduction in one ear at a time.
describe pure tone audiometry
- pure-tone air conduction hearing test determines the faintest tones a person can hear at selected pitches (frequencies), from low to high.
- earphones can be worn so that info can be obtained for each ear.
describe tympanometry and what does it measure
- tympanometry pushes air pressure into the ear canal, making the eardrum move back and forth.
- measures the pressure within the middle ear and the mobility of the eardrum.
what is tympanometry used to detect?
- assists in the detection of fluid in the middle ear, perforation of the eardrum, or wax blocking the ear canal.
when are bone anchored hearing aids (BAHAs) indicated?
- used by those whose anatomy makes use of the conventional aid difficult e.g. persistent otitis externa, external canal atresia.
describe a cochlear implant and when its used
- essentially a very strong hearing aid.
- electrode placed inside cochlea.
- for those with profound hearing loss.
what are the two otolith organs called? and what do they contain?
utricle and saccule
- each contains a sensory epithelium called the macula.
what is the orientation of the macula in the utricle?
horizontally oriented
what is the orientation of the macula in the saccule?
vertically oriented
describe the hair cells of the macula and otoliths
The macula in the utricle and saccule contains an array of hair cells whose stereocilia project into the otolithic membrane, a gelatinous mass that contains tiny crystals of calcium carbonate, called otoliths (literally, “ear stones”).
describe the ampullae of the middle ear, what they contain and their function?
- expanded areas at each end of the semiciruclar canals.
- they contain the sensory organ - the crista.
- movement of the crista is the stimulus for the vestibulo-ocular reflex.
describe the vestibulo-ocular reflex (VOR).
- the VOR stabilised gaze by moving eyes in order to compensate for head and body movement.
- this fixes image on retina for a clear sight.
which systems regulate body balance?
- visual.
- vestibular.
- proprioceptive.
what are three clinical conditions of the inner ear that affect balance?
- benign paroxysmal positional vertigo.
- vestibular neuritis.
- Meniere’s disease.
what is the aetiology of benign paroxysmal positional vertigo (BPPV)?
BPPV arises due to detachment of otoliths from the utricle of the inner ear.
- these detached particles can migrate into the semicircular canals , where they stimulate hair cells and lead to symptoms of vertigo.
what is the primary diagnostic test for BPPV?
Dix-Hallpike manoeuvre.
- involves a series of specific head movements that provoke the characteristic vertigo and nystagmus associated with BPPV.
what is the mainstay of BPPV management?
Epley manoeuvre
- aims to move detached otoliths out of the semicircular canal and back to the utricle where they originate.
what is vestibular neuritis?
inflammation of the vestibular nerve.
what is the initial clinical presentation of vestibular neuritis?
- acute onset of vertigo > nausea and vomiting.
- rarely hearing loss(if present, then can be truly called labyrinthitis).
- nystagmus present if seen early enough.
what is Meniere’s disease?
- inner ear disorder caused by increased fluid pressure in the endolympahtic spaces of the membranous labyrinth.
- This results in recurrent episodes of vertigo, hearing loss, and tinnitus.
what is the name of the ear drops that can be used in acute otitis externa?
sofradex
gentisone
- these are combined antibiotic/steroid drops.
- if tympanic membrane peforated or not visible use cilodex.
when are oral antibiotics indicated in acute otitis externa?
- cellulitis extending beyond the external ear canal.
- when the ear canal is occluded by swelling and debris and wick cannot be inserted.
- people with diabetes or compromised immunity with severe infection or high risk of severe infection.
what is the treatment for fungal otitis externa?
- topical clotrimazole or nystatin ear drops for two weeks.
what is the management of necrotising otitis externa?
- immediate referral.
- systemic anti-pseudomonas antibiotics.
- surgical debridement.
- control of diabetes.
what is an exostosis?
An exostosis is a benign (noncancerous) bone tumor.
what are osteomas?
Osteomas are benign head tumors made of bone.
what are the functions of the nose?
- nasal airway; humidifies and warms inspired air, removes noxious particles from the air.
- olfaction; smell and taste.
- immune; mucus contains IgA and IgE.
- speech; nasal airflow modifies speech and produces nasal clicks or click consonants.
what is choanal atresia?
- failed recanalisation of the nasal fossae during foetal development.
what is the management of choanal atresia?
- neonates are obligate nasal breathers > emergency as neonate will be unable to breathe.
- requires surgical repair.
at which part of the nasal cavity does air flow change from laminar to turbulent?
nasal valve, the narrowest site of upper respiratory tract
what are some possible functions of the paranasal sinuses?
- reduce skull weight
- physical buffer/crumple zone.
- vocal resonance
- humidification
- heat insulation
- immune barrier
label this nose
discuss the arterial supply of the external nose
- skin of external nose receives arterial supply from supratrochlear and dorsal nasal arteries (branches of opthalamic artery) and infraorbital artery (branch of maxillary artery).
- septum and alar cartilages recieve supply from the angular artery and lateral nasal artery (both branches of the facial artery).
discuss the venous drainage of the external nose
- venous drainage into the facial vein, then into the internal jugular vein.
why is this considered the danger triangle of face?
- highly anastomotic venous system of nose allows retrograde spread of infection to cavernous sinus via opthalamic veins- life and sight threatening!
discuss the sensory innervation of the external nose
Sensory innervation of the external nose is derived from branches of V1 and V2
the internal nose/nasal cavity is divided into which 3 parts? what is each part lined by?
- Vestibule - entrance to cavity, lined hair bearing skin.
- Respiratory region - lines by a ciliated pseudostratified epithelium, with mucus secreting cells.
- Olfactory region - at the apex of the nasal cavity, lined by olfacotry cells with olfacotry receptors.
discuss the vasculature of the internal nose
supply from branches of both internal and external carotid arteries:
- internal: anterior and posterior ethmoidal.
- external: Sphenopalatine artery, Greater palatine artery, Superior labial artery, Lateral nasal arteries.
what is the medical term for a nosebleed?
epistaxis
where is the most common site of epistaxis?
Little’s area (Kiesselback plexus) on anterior septum > easy to access and cauterise under local anaesthesia.
where does posterior epistaxis typically occur?
typically from Woodruff plexus > more likely to require nasal packing
What causes orbital cellulitis? and how is it managed?
- acute spread of infection from ethmoid or frontal sinuses
- requires IV antibiotics, nasal decongestants, CT scan +/- surgical drainage.
what is sinusitis? what determines whether it is acute or chronic?
Inflammation of lining of sinuses.
Acute (<3 months)- usually viral.
Chronic (>3 months)- with or without polyposis.
what is the presentation of chronic sinusitis?
+/- polyposis
nasal obstruction
chronic nasal discharge
affect on smell
what are the contents of the post nasal space/nasopharynx?
- adenoids and tubal tonsils- lymphoid tissue, make-up part of Waldayer’s ring.
- eustachian tube opening.
what can an enlarged adenoid cause?
- obstructs airway and eustachian tube.
- can cause glue ear > may require adenoidectomy and insertion of grommets.
what are common presenting symptoms in rhinology cases?
- nasal obstruction
- nasal discharge
- epistaxis
- facial pain
- nasal deformity
- anosmia (loss of smell)
- sneezing
what tool is used to examine the internal nose?
a nasal speculum with a light
what are the most common causative organisms in acute bacterial rhinosinusitis?
s. pneumoniae
H. influenza
which antibiotics can be used to treat acute rhinosinusitis?
beta-lactams: penicillins, cephalosporins.
macrolides: erythromycin, clarithromycin
investigations for nasal polyps?
- sweat test.
- RAST/skin testing.
- nasal smear.
- CT scan.
- MRI scan.
- nasendoscopy.
What is the treatment for nasal polyps?
- oral and nasal steroids.
- immunotherapy.
- traditional polypectomy.
- endoscopic sinus surgery.
outline the stepwise approach in managing epistaxis
- direct compression of nasal alae.
- cautery- can either be chemical or electrical.
- nasal packing.
- aggresive therapies; nasal balloon catheter and transnasal endoscopy with direct cautery/arterial ligation.
allergic rhinitis investigations
While allergic rhinitis can often be diagnosed based on clinical features and patient history, further investigations may be required in certain cases. These may include skin prick tests or blood tests for specific IgE antibodies to identify the allergen.
allergic rhinitis management
- Avoiding triggers
- Nasal irrigation with saline
- Intra-nasal or oral anti-histamines
- Regular intranasal steroids if initial measures are - ineffective
- Oral steroids for severe cases affecting quality of life
what are the main arteries that can undergo ligation in severe epistaxis?
- shenopalatine.
- anterior/posterior ethmoidal.
- external carotid artery.
what vertebral levels does the larynx extend from?
C3-6
what is the function of the larynx?
- flow of air between trachea and mouth > movement of vocal cords produce voice (phonation) and alter pitch and volume.
- protect the airway from aspiration > epiglottic closure, cough relfex.
discuss the motor innervation of the larynx
- all muscles of larynx = recurrent laryngeal nerve.
- except for cricothyroid muscle = superior laryngeal nerve.
discuss the sensory innervation of the larynx
Sensation via vagus nerve:
- above vocal cords = superior laryngeal nerve.
- below vocal cords = recurrent laryngeal branch.
What are the three principles of voice production?
Must have three main things to produce recognisable voice:
1. air flow into the larynx (generated by the lungs and diaphragm).
2. vibration/mucosal wave (e.g. on the vocal fold in the larynx during vocal cord adduction).
3. resonance in the upper aerodigestive tract and use of the pahrynx, mouth, tongue and lips to manipulate the sound produced by the larynx into words and sounds.
describe the sensory and motor innervation of the pharynx.
- sensory innervation via glossopharyngeal (CN IX) and vagus (CN X) nerves.
- motor innervation via vagus nerve (CN X).
describe the motor innervation of the tongue
- palatoglossus muscle: vagus nerve (CN X).
- all other muscles: hypoglossal nerve (CN XII).
describe the sensory innervation of tongue
- glossopharyngeal nerve, CN IX (general and special sense (taste)).
- lingual nerve, CN V (general sensory).
- chorda tympani, CN VII (special sensory).
what are the boundaries of the anterior triangle of the neck?
superiorly - inferior border of the mandible (jawbone).
laterally - anterior border of sternocleidomastoid.
medially- sagittal line down the midline on neck.
Investing fascia covers the roof of the triangle, while visceral fascia covers the floor.
label these muscles and state which area of the neck they are from
- anterior triangle of the neck.
what is the collective action of the suprahyoid muscles?
- they all act to elevate the hyoid bone- an action involved in swallowing.
label these muscles and state which area of the neck they are from
anterior triangle
label these muscles and state which area of the neck they are from
anterior triangle
label these muscles and state which area of the neck they are from
anterior triangle
Which arteries supply the anterior triangle of the neck?
- common carotid: external and internal carotid arteries.
- superior thyroid (ECA).
- inferior thyroid artery (thyrocervical trunk).
which veins drain the anterior triangle of the neck?
- anterior jugular veins.
- internal jugular veins.
- superior thyroid veins.
- middle thyroid veins.
which nerves innervate the anterior triangle of the neck?
- vagus nerve (CN X).
- hypoglossal nerve (CN XII).
- part of sympathetic trunk.
what are the branches of the external carotid artery? (HINT: Some Anatomists Like Freaking Out Poor Medical Students)
- superior thyroid artery
- ascending pharyngeal artery
- lingual artery
- facial artery
- occipital artery
- posterior auricular artery
- maxillary artery
- superficial temporal artery
which structures form the borders of the posterior triangle of the neck?
anterior- posterior border of sternocleidomastoid.
posterior- anterior border of the trapezius muscle.
inferior- middle 1/3 of the clavicle.
roof- investing layer of fascia.
floor- paravertebral fascia
which artery supplies the posterior triangle of the neck?
subclavian artery (third part)
which vein drains the posterior triangle of the neck?
external jugular vein (inferior aspect)
which nerves innervate the posterior triangle of the neck?
- accessory nerve (CN XI).
- branches of cervical plexus.
- upper brachial plexus.
del
list the superficial lymph nodes of the head and neck
- occipital
- pre and post auricular
- parotid
- submental
- submandibular
del
describe Waldeyer’s ring
- oropharyngeal mucosa covering a bed of lymphatic tissue.
- first line of defense agains microbes that enter the body via nasal and oral routes:
- lingual tonsils.
- palatine tonsils.
- tubal tonsils.
- pharyngeal tonsil.
describe the thyroid gland
- butterfly shaped, vascular, red-brown endocrine gland situated in the midline of the anterior neck.
- composed of two lobes and an isthmus that joins the lobes > pyramidal lobe may be found at times.
- the largest of the endocrine glands.
which vertebral levels does the thyroid gland extend from?
C5-T1
describe the parathyroid glands
- small, brown coloured, oval glands situated in the posterior aspect of the thyroid.
- usually four glands; superior x2, inferior x2.
what is the arterial supply of the thyroid gland?
- superior thyroid artery.
- inferior thyroid artery.
- thyroid ima.
what is the venous drainage of the thyroid gland?
superior, middle and inferior thyroid veins
what is the arterial supply of the parathyroid glands?
inferior thyroid artery
what is the venous supply of the parathyroid glands?
superior, middle and inferior thyroid veins.
is a negative Rinne’s test normal or abnormal?
abnormal > means bone conduction is greater than air.
list the suprahyoid muscles
Stylohyoid
Digastric
Mylohyoid
Geniohyoid
list the infrahyoid muscles
Omohyoid
Sternohyoid
Thyrohyoid
Sternothyroid
