Gregory Giles Flashcards
Where does the facial nerve arise
Between pons and medulla as motor root and sensory root which pass through internal auditory meatus into facial canal of petrous temporal bone
Where are upper motor neurones
Where are lower motor neurones
From cortex to brainstem
From brainstem to motor components
What is the pathway of motor route of facial nerve
7
Emerges between pons and medulla
Through internal auditory meatus into facial canal of petrous temporal bone
Travels laterally to medial wall of middle ear
Joins nervus intermedius to form facial nerve in petrous temporal bone
Sharp turn at geniculate ganglion
Greater petrosal nerve, nerve to stapedius and chorda tympani given off
Exits through stylomastoid foramen into infra temporal fossa where small sensory branch innervates skin over external auditory meatus, upon emerging nerve entirely motor
Are the upper motor neurones for upper 1/3 of the face contralateral, ipsilateral or bilateral
Bilateral
Are upper motor neurones for lower 2/3 of face contralateral, ipsilateral or bilateral
Controlateral
What innervates muscles of facial expression and where do the muscles originate and insert
Facial nerve
Surface of skull
Dermis of skin
What are the layers of the face
4
Skin
Subcutaneous fat
Musculoaponeuritic system
Deep fascia
What gives blood supply to muscles of facial expressions
Internal carotid artery and external carotid artery
What is the pathway of facial nerve in petrous temporal bone
5
Originate between pons and medulla
Through IAM then travel laterally to medial wall of middle ear
Sharp turn at geniculate ganglion to run horizontally across medial wall of middle ear
Nerve reaches posterior wall of petrous temporal bone
Sharp turn to exit through stylomastoid foramen into infra temporal fossa
Which branches of facial nerve carry fibres of nervus intermedius
4
What do they innervate
Lesser superficial petrosal- parasympathetic fibres to parotid gland
Greater superficial petrosal- sensory fibres to palate, parasympathetic fibres to lacrimal and mucous gland
Chorda tympani- sensory fibres to anterior 2/3, parasympathetic fibres to submandibular and sublingual gland
Which branches of facial nerve carry fibres of motor route
5
What do they innervate
Nerve to stapedius- stapedius muscle of inner ear
Nerve to digastric- digastric muscle posterior belly
Nerve to stylohyoid- stylohyoid muscle
Posterior auricular nerve- muscles around ear
Facial motor branches- muscles of facial expression
What is the pathway of greater superficial petrosal nerve
4
Arises from geniculate ganglion in facial canal
Passes through greater superficial petrosal foramen into middle cranial fossa
Joined by deep petrosal nerve from internal carotid plexus to form nerve of pterygoid canal
Nerve of pterygoid canal passes through foramen lacerum to pterygopalatine ganglion
What is the pathway of chorda tympani
Branches off in mastoid section of facial nerve
Passes across tympanic membrane
Pterygotympanic fissure into infra temporal fossa
Joins lingual nerve and passes to submandibular ganglion
What is the pathway of parasympathetic, sensory and sympathetic input through ganglia
Parasympathetic: relay and synapse in ganglion
Sensory: pass through
Sympathetic: pass through
What is the difference between the courses of parasympathetic and sympathetic fibres?
Parasympathetic has long pre ganglionic course and short post ganglionic coarse
Sympathetic has short pre ganglionic and long post ganglionic coarse
What does submandibular ganglion house
Parasympathetic secretomotor fibres to SM and SL glands, sensory fibres to anterior 2/3 tongue
What does otic ganglion house
Parasympathetic secretomotor fibres to parotid gland
What does meckels ganglion house
Secretomotor fibres to lacrimal glands, mucous and serous glands of palate, nose and paranasal sinuses
What does cilliary ganglion house
Fibres to sphincter pupillae and cillary muscle
What is Frey’s syndrome
What is it’s symptom
Regrowth of nerve supply to parotid gland resulting in nerve supply to sweat glands
Gustatory sweating
What is Ramsay hunt syndrome
What is it’s symptoms
Herpes zoster infection in geniculate ganglion
Facial nerve paralysis, ear pain, taste loss, dry mouth and eyes, vesicles in ear canal, tongue and hard palate
What is horners syndrome
What is it’s symptoms
Interuption of sympathetic nerve supply to eye
Miosis, partial ptosis, loss of hemifacial sweating
What is the physiology of hearing?
5
Vibrations captured by auricle and transmitted to external auditory meatus
Vibrations stimulate tympanic membrane and impulses transmitted through ossicles to cochlear
Vibrations pass through oval window to cochlea via Scala vestibuli
Impulses travel through cochlea stimulating organs of Corti which transduce vibrations to nerve impulses
Impulses travel to cerebrum by cochlear nerve you be analysed in auditory cortex
What are the components of external ear
3
Auricle
External auditory canal
Tympanic membrane
What is the thickness of tympanic membrane
0.1 mm
What are the components of middle ear
4
Eustacian tube
Ossicles
Oval window
Round window
What is the role of eustacian tube
Connect muliddle ear to nasopharynx to equalise pressure
What are the ossicles called
Malleus, incus, stapes
Where does oval window sit between
Middle ear and vestibule
Where is the inner ear located
Petrous temporal bone
What are the components of inner ear
3
Vestibule
Semicircular canals
Cochleae
What are the otolith organs
Where are they
What do they do
Utricle and saccule
Vestibule
Balance
What are the semicircular canals filled with
What do they do
Endolymph
Balance
What are the ducts of the cochlea called And what are they filled with
Scala vestibule: perilymph
Cochlea duct: endolymph
Scala tympani: perilymph
What is the tip of the cochlea called
Helicotrema
What is the membrane between Scala vestibuli and cochlea duct called
What is the membrane between Scala tympani and cochlea duct called
Reissners membrane
Basilar membrane
Which membrane houses organs of Corti
Basilar membrane
How are ions distributed in cochlea
Scala vestibuli and Scala tympani high in sodium
Cochlea duct high in potassium
How many hair cells in the organ of Corti and how are they arranged
15000 hair cells
4 parallel rows
What separates the stereocillia from the endolymph of the cochlea
Tectorial membrane
What is the process of mechanico neural transduction in the cochlear
6
Pressure waves begin at oval window and travel through Scala vestibuli
Parts of reissners membrane are displaced to create vibratory wave in potassium rich endolymph
Steriocillia of hair cells are displaced by vibratory wave which opens mechanically gated ion channels of hair cells
Potassium ions flow into hair cells leading to change in membrane potential, triggering the opening of vaultage gated calcium ion channels
Calcium enters which triggers neurotransmitter release
AP created in vestibulocochlear nerve afferents
What makes up the vestibular system
3
Semicircular canals
Utricule
Saccule
What are semi circular canals filled with
What structure sits at the base of each canal
What do the semi circular canals detect
Endolymph
Ampulla
Movement of the head in different planes and rotation
What does the utricle detect
What does it use to detect this
Linear acceleration and head tilts in the horizontal plane
Small stones, viscous fluid, hair cells
What does the saccule detect
What does it use to detect this
Movement in vertical plane
Small stones, viscous fluid, hair cells
What are the types of hearing loss
Conductive- sounds unable to pass freely to inner ear
Sensorineural- damage to hair cells in cochlea or damage to vestibulocochlear nerve
Prespycussis- age related hearing loss due to histological changes
Why is amalgam being faded out
8
Minimum intervention Material durability Aesthetics Patient preference Potential occlusal loading Mercury toxicity and the environment Time taken to complete restoration
What are the advantages of amalgam 5
Strong and durable Similar wear rate to enamel Seals at margins due to corrosion Doesn’t alter sub gingival plaque biofilm Reliable
What are the disadvantages of amalgam
4
Colour
Mechanical retention
Must remove healthy tissues
Waste management
When is amalgam used
2
Large class 2 restorations Deep sub gingival restorations
When is amalgam not used
5
Class 1 restorations Primary dentition Pregnant or breastfeeding women Those with impaired renal clearance Under 15s
How much mercury escapes amalgam fillings
3-17 micrograms of mercury vapour daily
How much mercury in the urine of those with amalgam restorations
5 micrograms per litre
How much mercury in the urine of dentists
Below 10 micrograms per litre
What level of mercury in urine can lead to mercury poisoning
25-50 micrograms per litre
What level of mercury in urine is seen during neurological symptoms of mercury poisoning
Above 500 micrograms per litre
When was minimata convention signed
How many countries signed
What was agreed
October 2013
128
Reduce mercury effect on environment in 4 years
Which nerve supplies skin of face
Trigeminal nerve
What are the trigeminal nuclei called
4
Menecephalic nucleus
Chief sensory nucleus
Motor nucleus
Spinal nucleus
Which fissure does V1 run through
Superior orbital fissure
Is the ophthalmic nerve sensory, motor or mixed
Sensory
After the trigeminal ganglion where does the ophthalmic nerve run
Lateral wall of cavernous sinus
What are the three main branches of ophthalmic nerve
Nasocilliary
Frontal
Lacrimal
What are the branches of nasocilliary branch of V1 and what do they do
5
Nerve to ciliary ganglion- sensory info from eyeballs via short cilliary nerves
Long cilliary nerve- sensory info from cilliary body, iris and cornea, innervate dilator papillae
Posterior ethmoidal- sensory fibres to posterior ethmoidal and sphenoidal sinuses
Anterior ethmoidal- sensory fibres to anterior ethmoidal cells, nasal mucosa, skin of nasal dorsum
Infratrochlear- sensory fibres to lacrimal sac, conjunctiva, eyelids, upper lateral aspect of nose
What are the branches of frontal branch of V1 and what do they do
2
Supra orbital nerve- supplies scalp up to lambdoidal suture, pericranium and upper eyelid
Supra trochlear nerve- skin of lower forehead conjunctiva and upper eyelid
What does the lacrimal branch do
What is a special feature of lacrimal branch
Supplies lacrimal gland, conjunctiva, upper eyelid
Communicating branch with zygomaticotemporal branch of maxillary nerve
Is the maxillary nerve motor sensory or mixed
Sensory
Which foramen does the maxillary nerve go through
Into which fossa
Foramen rotundum
Pterygopalatine fossa
What branch is given of V2 before foramen rotundum
Meningeal branch
What are the branches of pterygopalatine ganglion
5
Pharyngeal Lesser palatine nerve Greater palatine nerve Nasopalatine nerve Nasal branch
What branch leaves maxillary nerve before inferior orbital fissure
Posterior superior alveolar nerve
After foramen rotundum what does maxillary nerve pass through
Inferior orbital fissure
What does V2 branch into after inferior orbital fissure
Zygomatic nerve
Infra orbital nerve
What are the branches of zygomatic nerve of V2
Zygomaticofacial
Zygomaticotemporal
What are the branches of infra orbital nerve of V2
Middle and anterior superior alveolar nerves
Palpebral branch
Nasal branch
Superior labial branch
Where is pterygopalatine ganglion located
Pterygo palatine fossa
What innervates the pterygopalatine ganglion
Greater petrosal branch of facial nerve
What does the pterygopalatine ganglion supply parasympathetic innervation to
4
Lacrimal gland
Mucosal glands of oral cavity
Mucosal glands of nose
Mucosal glands of pharynx
What does the meningeal branch of V2 do
Supplies dura mater in middle cranial fossa with sensory fibres
What does zygomaticotemporal nerve supply
What does zygomaticofacial nerve supply
Skin around temples, lacrimal nerve
Skin of cheek
What does posterior superior alveolar nerve supply
Molars, gingivae, by cal bone and maxillary sinus
What does the anterior superior alveolar nerve supply
Incisors, canines, premolars, mesiobuccal route of 6, maxillary sinus, middle superior alveolar nerve
What does the palpebral branch supply
Skin of lower eyelid and conjunctiva
What does nasal branch supply
Skin of nose
What does superior labial branch supply
Skin of upper lip
What shape is the bony orbit
Pyramid shaped
Where in the orbit is the lacrimal fossa
Medial wall anteriorly
Where is the lamina papyracea
What is this
Paper thin plate of bone overlying ethmoid sinus on medial wall of orbit
What foramen are located on medial wall of orbit
3
Optic canal
Posterior ethmoidal foramen
Anterior ethmoidal foramen
Which bones form lateral wall of orbit
2
Zygomatic bone anteriorly and greater wing of sphenoid posteriorly
Where is the lateral tubercle located
Zygomatic bone in lateral wall of orbit
What nerve passes through zygomatico temporal foramen
Zygomaticotemporal nerve
What nerve passes through zygomaticofacial foramen
Zygomaticofacial nerve
Which bone forms roof of orbit
Frontal bone
What structures does the infra temporal fossa house
5
Temporalis Maxillary artery Maxillary vein Buccal fat pads Temporalis fat pads
What structures does the pterygopalatine fossa house
3
Pterygopalatine ganglion
Maxillary nerve
Infra orbital branch of maxillary artery
Where does superior orbital fissure lye
At orbital apex between greater and lesser wings of sphenoid
What is the annulus of zinn
A tight fibrous ring dividing superior orbita fissure into intra coronal and extra coronal spaces
Also acts as origin for rectus muscles
What is the acronym for nerves passing through superior orbital fissure
Luscious French Tarts Sitting Naked In Anticipation
Which nerves pass through superior orbital fissure outside annulus of zinn
Lacrimal nerve v1
Frontal nerve v1
Trochlear nerve CN 4
Which nerves pass through superior orbital fissure within annulus of zinn
Superior division oculomotor CN3
Nasocilliary nerve V1
Inferior division occulomotor CN3
Abducens CN 6
Where do the extra ocular muscles insert
Pierce fascial sheath to insert into sclera
What suspends the eye in place
Check ligaments
Suspensory ligament of Lockwood
What are the ocular muscles and what do they do
6
Lateral rectus- rotates eye laterally
Medial rectus- rotates eye medialy
Superior rectus- rotates eye superiorly
Inferior rectus- rotates eye inferiorly
Superior oblique- rotates downward and outward with medial rotation
Inferior oblique- rotates upwards and outwards with lateral rotation
Which nerve has fibres passing to cilliary ganglion to hitchhike with opthalmic nerve
Parasympathetic fibres of oculomotor nerve
What are fibres from cilliary ganglion responsible for
Miosis- constriction of pupil
Accommodation- change in focus
Where is the lacrimal gland and what type of gland is it
Lacrimal fossa
Exocrine gland
Where do tears produced by lacrimal gland flow
Lacrimal sac
Naso lacrimal duct to inferior meatus of nose
