Lecture 6 (head pt 3) Flashcards
What sinuses make up the paranasal sinuses? List each and whether they’re paired or unpaired
Frontal: Paired
Ethmoid: midline/paired
Sphenoid: midline
Maxillary: paired
1) Where does the frontal sinus run through/ go?
2) What innervates it?
1) Frontal nasal duct into ethmoidal infundibulum of middle meatus
2) Innervated by CN 6
Where do the 3 groups of cells of the ethmoid sinuses open to?
1) Anterior cells: drain into infundibulum of middle meatus
2) Middle cells: open directly into middle meatus
3) Posterior cells: form the bulla, open directly into superior meatus
1) Where are the sphenoid sinuses?
2) Do they open into the nasal cavity?
1) Occupy the cavity in delicate sphenoid bone, drain into. 2) No real opening into the nasal cavity.
What drains the maxillary sinuses, and where do they drain into?
Maxillary ostium; into the middle meatus
What is the rich plexus where all the arteries supplying the septum anastomose? What is the clinical significance of this area?
Keisselbach; profuse epistaxis (nosebleeds)
Where do the veins that drain the septum go?
Into sphenopalatine, facial, and ophthalmic veins
What nerves innervate the nose? (2)
1) Posterio-inferior ½ to 2/3 of cavity is primarily: CN V2 (maxillary n.)
2) Anterior superior cavity (both septum & lateral wall) is primarily: anterior ethmoidal nerves from CN V1 (ophthalmic n.)
True or false: Mucosa of the oral cavity is continuous with the gingiva
True
Where can you find gingiva?
Around the neck of teeth
What structure will you find on the buccal side of the mandibular second molar?
Opening of the parotid duct
True or false: There’s both ipsilateral and contralateral drainage of cheeks, lips, and chin lymphatics
True
True or false: infections don’t easily spread from one side of the face to another
False; infections and cancers can spread easily because there’s both ipsilateral and contralateral lymphatic drainage
What covers the roots of teeth?
Cementin
Describe the path of V3 through the lower face
Into mandible at mandibular foramen; provides alveolar nerves
Then comes out mental foramen for skin
Where is lidocaine placed to numb an entire side of the bottom teeth?
V3
1) What does the hard palate separate?
2) What does the soft palate separate?
1) Oral cavity from nasal cavity
2) Oral cavity from nasopharynx
Where are the lingual tonsils found?
Posterior 1/3 of tongue
1) What is the soft palate?
2) What is it made of?
3) How is it attached?
1) Movable posterior 1/3rd of the palate
2) Mainly muscular
3) Palatine aponeurosis; attached to hard palate anteriorly
What does the soft palate do?
Assists in swallowing and prevents bolus entering nasal cavity (by moving/ closing while swallowing)
1) What provides sensory innervation for the gag reflex?
2) What provides motor innervation for the gag reflex?
1) CN IX afferent
2) CN X efferent
What provides motor innervation for tongue protrusion?
CN XII (12)
What nerve provides taste sensation?
CN VII chordae tympani
What nerve provides somatic sensory innervation to the oral cavity?
CN V3 (lingual n.)
Name 3 muscles of the soft palate
1) Palatoglossus
2) Palatopharyngeus
3) Uvula
What does the palatoglossus muscle do?
Forms palatoglossal arch
What does the palatopharyngeal muscle do?
Forms palatopharyngeal arch
What is the uvula?
A muscle of the soft palate
How are the palates innervated with sensory nerve fibers?
Branches of CN V2 (maxillary n; foramen rotundum) (that pass through pterygopalatine ganglia)
What two nerves supply the palates with motor fibers?
1) CN V3: Tensor veli palatini (forms palatine aponeurosis)
2) Pharyngeal plexus from vagus n. CN X: All other (motor) muscles of soft palate (& much of oral pharynx)
1) What nerve does the pharyngeal plexus of nerves come from?
2) What does this nerve do?
1) Vagus n.
2) Acts as motor arm of GAG reflex
True or false: Only way CNV conveys motor is via V3, mandibular n., (foramen ovale)
True
What are two types of tonsil inflammation?
Tonsillitis and peritonsillar abscess
What are the 3 parts of the ear?
External, middle, and internal
1) What term do you use to refer to both ears?
2) What term do you use to refer to the left ear?
3) What term do you use to refer to the right ear?
1) AU(bilateral)
2) AS (left)
3) AD(right)
What are the 3 parts of the external ear?
1) Auricle (Pinna)
2) External acoustic meatus of Auditory Canal (EAC)
3) Tympanic membrane (TM) (separates outer and middle)
What two nerves provide primary innervation to skin of auricle?
1) Great auricular n.
2) Auriculotemporal n. (CN V3)
What two nerves have a minor contribution to innervation of skin of auricle?
1) CN7
2) CN10
What two nerves innervate the auditory canal and external TM?
CN V3 & CN X
What does it mean if the tympanic membrane is in a neutral position?
The pressure is equal between the middle ear and outside
1) Where do PE tubes go?
2) What do they do?
1) Through anterior inferior aspect of TM near cone of light
2) Allows pressure equalization until Eustachian tube heals itself.
True or false: air conduction is usually more efficient than bone conduction
True
Do you usually hear through air conduction, bone conduction, or both?
Both
What are the two openings of the middle ear?
1) Posterosuperior with mastoid antrum (i.e. to mastoid air cells)
2) Pharyngotympanic tube (aka Eustachian tube)
What is found within the middle ear/ tympanic cavity? (4 things)
1) Auditory ossicles
2) Tendons of stapedius and tensor tympani m.
3) Chorda tympani n. (br. of CN VII )
4) Tympanic plexus of nerves
Is the carotid plexus sympathetic or parasympathetic?
Sympathetic
1) What is the malleolus (mallet) attached to and what does it articulate with?
2) What does the incus (anvil) articulate with?
1) Attached to TM, articulates with Incus
2) Articulates with malleolus and stapes
1) What is the stapes (stirrup)?
2) How are sound waves converted from air to mechanical force?
1) Base or footplate occupies the oval window
2) At TM through ossicles
What allows for 10x vibratory amplification in the middle ear?
Base of stapes is considerably smaller than TM
Two muscles of middle ear slide 43
1) What do the two muscles of the middle ear collectively do?
2A&B) Name the two muscles of the ear, describe what each does, and what each is innervated by
1) Resist or dampen movement of auditory ossicles
2a) Tensor tympani: Inserts into handle of malleolus
-CN V3
2b) Stapedius: Pyramidal eminence that inserts onto stapes
-CN VII (nerve to stapedius)
What equalizes pressure between the middle ear cavity and external atmosphere?
Eustachian tube; opens into nasopharynx
Describe the Pharyngotympanic tube/ Auditory canal/ Eustachian tube; what is it made of and what does it open to?
1) Bony and cartilaginous parts
2) Into nasopharynx
What does the vestibulocochlear organ do? (2 things)
Sound and balance
Where is the vestibulocochlear organ?
Embedded in petrous part of temporal bone
What is the otic capsule?
The boney skeleton in the internal ear
What are the two labyrinths of the inner ear? Describe each
1) Boney labyrinth: fluid filled space of the surrounded by otic capsule
2) Membranous labyrinth: sacs and ducts suspended in the boney labyrinth
What are the two parts of the membranous labyrinth? What does each contain?
1) Cochlear labyrinth
-Cochlear duct
2) Vestibular labyrinth
-Utricle and saccule
1) What is the cochlea? Where is it and what does it contain?
2) What does the vestibule of the boney labyrinth contain?
1) The cavity of the boney labyrinth that contains the cochlear duct (hearing)
2) Contains the utricle and saccule for balance
What nerve is Meniere’s disease associated with?
CN7
What are the 3 symptoms of Meniere’s disease (CN7)? Are these bilateral or ipsilateral?
1) Tinnitus
2) Vertigo
3) Hearing loss
-Often unilateral symptoms
What is an acoustic neuroma? Are its symptoms bilateral or ipsilateral?
1) Peripheral lesion (cerebellopontine angle) of CN7
2) Ipsilateral symptoms
The small area between cornea and iris is the _______________
anterior chamber
The area between the lens and retina is the __________________
posterior chamber
Where do styes usually occur?
1) The ciliary glands of the eyelashes
2) Tarsal glands (points towards cornea)
What muscle closes the eyelids? What innervates it?
1) Orbicularis oculi
2) CN VII (facial expression)
1) What two muscles open the eyelid?
2) What innervates these?
1) Levator palpebrae superioris and superior tarsal mm. opens lid
2) CN 3 somatic and visceral motor
When the sclera of someone’s eye becomes red, what is occurring?
Subconjunctival hemorrhage
True or false: the lacrimal gland is above the rim of the orbit and can’t usually be palpated
True
1) What do the lacrimal canaliculi terminate as? What do they lead to?
2) What do they do?
1) The lacrimal punctum (openings of canaliculi); lead to lacrimal lake w papillae [elevation in eyelids].
2) Convey fluid to nasolacrimal duct [then goes to nasal cavity]
1) What leads to the nasolacrimal duct?
2) Where does it drain?
1) Lacrimal sac
2) Into nasal cavity into inferior meatus (lateral to the inferior concha)
What can look similar to a stye?
Inflammation of lacrimal sac
1) What makes up the superior walls of the orbit? (1)
2) What makes up the medial wall of the orbit? (4)
1) Frontal bone
2) Ethmoid, frontal, lacrimal, and sphenoid (optic canal)
1) What makes up the lateral walls of the orbit? (2)
2) What makes up the inferior wall of the orbit? (3)
1) Frontal process of zygomatic, greater wing of sphenoid
2) Maxillary, zygomatic, palatine
What does the greater wing of the sphenoid separate?
Orbit from middle cranial fossa and temporal lobes
Where is the apex of the orbit?
Optic canal in the lesser wing of sphenoid
What is the orbit lined with?
Periorbita (periosteum)
What is the periorbita of the orbital cavity continuous with? (5 things)
1) Periosteal layer of dura at optic foramen and superior orbital fissure
2) Periosteum covering the external surface of the cranium at margin of orbits and inferior orbital fissure
3) Orbital septa at orbital margins
4) Fascial sheaths of the extra ocular m.
5) Orbital facia covering eyeball
What is the orbital septa at orbital margins continuous with?
Periorbita (periosteum) of the orbit
What produces aqueous humor?
Ciliary body
1) What can happen if the aqueous humor isn’t drained? 2) What can this cause?
1) Can increase pressure in eye if aqueous humor isn’t drained
2) Pressure increase can cause glaucoma (which is nerve damage b/c of pressure)
1) What is periorbital (pre-septal) cellulitis?
2) Where does venous blood here flow?
1) A skin and soft tissue infection around that eye that is anterior to the orbital septum
2) Into the cavernous sinus
1) What is orbital cellulitis?
2) What can cause it?
3) How is it diagnosed?
4) What are some complications it can cause?
1) Infection of the orbital tissue posterior to the orbital septum.
2) An external focus of infection (e.g., a wound), infection that extends from the nasal sinuses or teeth, or metastatic spread from infection elsewhere.
3) CT/MRI
4) Can become an orbital abscess, which can easily become a subperiosteal abscess, which can become cavernous sinus thrombosis
What bones of the orbit are very thin?
Medial and inferior bones
Describe the properties of the sclera
Fibrous, shape, relatively avascular, has attachments of external and internal m.
1) What is the limbus?
2) How large is it, what color, and what does it contain?
1) Angle formed at junction of sclera and cornea
2) 1mm, grey, with numerous capillary loops to nourish the cornea
1) Name 2 attributes of the cornea.
2) What two things keep it moist?
1) Transparent, avascular
2) Bathed in lacrimal fluid and aqueous humor on surface
What are the 3 parts of the fibrous layer of the eyeball?
Sclera, limbus, and cornea
1) What nerve provides sensory innervation for the corneal touch reflex?
2) What provides motor innervation for the corneal reflex?
1) CN V1 (afferent)
2) CN 7 (efferent)
What are the 3 parts of the vascular layer of eyeball?
1) Choroid (uveal tract)
2) Ciliary body/processes (involved w aqueous humor and fibers)
3) Iris/pupil
1) What is the choroid?
2) What does it do? Where is it attached?
3) What is it continuous with?
4) What does it cause? [hint: red]
1) Vascular bed between sclera and retina
2) Nourishes retina; attached to retina’s pigmented layer
3) Continuous anterior with ciliary body and iris
4) Red reflex in infant
What part of the eye causes ‘red eye’ in flash photography?
The choroid
1) What part of the ciliary body is constricted? By sympathetic or parasympathetic?
2) What part of the ciliary body is dilated ? By sympathetic or parasympathetic?
1) Parasympathetic constricts sphincter papillae m,
2) Sympathetic dilates pupil dilator pupillae
1) What does ciliary body provide attachment for? How? What does this allow for?
2) What does it fold on? What does this form and what does that do?
3) Where does it get its innervation from?
1) The lens via zonular fibers; allows for fine focus & accommodation
2) On internal surface of body; ciliary process, secretes aqueous humor
3) Parasympathetic from ciliary ganglia (from CNIII)
Are ciliary ganglia sympathetic or parasympathetic and motor or sensory? What do they do?
Parasympathetic motor ganglia; allow for constriction of the iris, pupil, and accommodation
1) What does the iris control?
2) What innervation causes it to constrict the pupil?
3) What innervation causes it to dilate the pupil?
1) Aperture (pupil) for light regulation
2) Parasympathetic via ciliary ganglia to sphincter pupillae
3) Sympathetic to dilator pupillae
1) Sympathomimetic drugs act like ____________ stimulation to dilate the eye
2) Parasympatholytic drugs do what two things?
1) Sympathetic
2) Antagonize parasympathetic receptors to dilate the eyes AND inhibits accommodation
What cranial nerve parasympathetically stimulates the iris? How?
CN III; postsynaptic fibers from ciliary ganglia
What two nerves are involved in pupillary response?
1) CN II (afferent/ sensory)
2) CN III (efferent/ motor)
Describe pupillary response in terms of what it tests and the innervation involved
1) Tests retina (sensory light receptors) and Optic n., CN II, (afferent limb) on ipsilateral side
2) Tests sphincter pupillae muscle on ipsilateral (direct pupillary constriction) and contralateral side (consensual pupillary constriction)
2) Oculomotor n., CN III, parasympathetic post ganglionic nerve fibers via ciliary ganglia and ciliary n. (efferent limb)
What are the two parts of the retina?
1) Optic part
2) Nonvisual part
What are the two parts of the optic part of the retina? What does each do?
1) Neural layer: sensitive to visual light
2) Pigment layer: absorbs light, reduce scatter
1) What is the nonvisual part of the retina?
2) What does it extend anteriorly over?
1) Anterior extension of pigmented layer of retina
2) Ciliary body and iris
What is the ocular fundus?
Part of eye light strikes when entering eye; what you can visualize during fundoscopic exam
1) What happens at the optic disc/papilla?
2) Why is this location unique?
1) Optic n. enters and radiates to periphery
2) No receptors; our vision’s blind spot
What is lateral to the optic disc? What does it do?
Macula/fovea; specialized for acuity vision
1) What is at the center of the macula? What is this in our vision?
2) What is unique about the center of the macula?
1) Fovea centralis; area of most acute vision
2) Fovea lacks capillary network visible elsewhere deep to retina
True or false: the macula and fovea are difficult to appreciate with handheld ophthalmoscope
True
What are the important parts of the ocular fundus?
1) Optic disc/papilla
2) Macula/fovea
Where does most refraction of the eye occur?
Cornea
What 5 parts of the eye are reflective?
1) Tear film
2) Cornea
3) Aqueous humor
4) Lens (accommodation)
5) Vitreous humor
What is the pathway of light from the environment to the retina? (8 steps)
1) Environment
2) Cornea
3) AC (aqueous humor)
4) Through pupil
5) PC (aqueous humor)
6) Lens
7) Vitreous
8) Retina/optic nerve
1) What does the pathway of light typically cause?
2) What can change this?
1) Normal red reflection (RR)
2) Pathology of any of the media can distort or block/change RR
What are cataracts?
Clouding of the lens (clear fibers become clouded)
Aqueous humor:
1) Where is it produced
2) Where does it flow through?
3) What does it do?
1) By ciliary process in posterior chamber
2) Flows thru pupil into anterior chamber
3) Nourishes lens and cornea
1) What drains the aqueous humor? Where does it go?
2) What removes it?
3) What is this similar to?
1) Drains thru trabecular meshwork at iridocorneal angle into scleral venous sinus (canal of Schlemm)
2) Removed by limbal plexus
3) Like CSF: production – flow – absorption
Why don’t PCPs dilate the iris?
Because they usually don’t have the tools to check intraocular pressure before or after dilation, and dilation is a risk if intraocular pressure is high
1) What are the types of glaucoma?
2) What is it a common cause of?
3) What typically accompanies it?
4) What causes it?
1) Chronic or acute
2) Blindness
3) Increased IOP
4) Compression of retina and retinal arteries causing damage to optic nerve
What extraocular muscles of the eye does CN 3 innervate?
All except lateral rectus (LR) and superior oblique (SO)
1) What are the two oblique extraocular muscles?
2) What are they innervated by?
1) Superior oblique (SO): CN 4 (Trochlear n.)
2) Inferior oblique (IO): CN 3 (Oculomotor n.)
What are the 4 recti extraocular muscles of the eye? Name what each is innervated by
1) Superior rectus (SR): CN 3
2) Inferior rectus (IR): CN 3
3) Medial rectus (MR): CN 3
4) Lateral rectus (LR): CN 6 (Abducens n.)
What does absence of the tarsal muscle cause?
Ptosis or droopy upper lid
What are the categories of extraocular muscles?
1) Two obliques
2) Four recti
True or false: The orbital axis is different from the visual axis
True
1) How would you test the lateral rectus muscle of the right eye?
2) How would you test the superior oblique muscles of both eyes?
1) Look to the right for lateral rectus (CN6 abducens) of right eye
2) Look down and to test your superior obliques (CN4)
If someone had complete CN III palsy (an injury due to increased intracranial pressure from bleed), what would this cause? Why? (5 things)
1) Ptosis: unopposed orbicularis oculi
2) No pupillary light reflex
3) Dilated pupil (“blown pupil”): unopposed dilator pupillae m. due to loss of parasympathetic input
4) No accommodation
5) Eyeball (pupil) fully abducted and depressed: unopposed LR and SO
What would a CN 6 (Abducent n.) injury cause? (2 things)
1) Affected abduct pupil on ipsilateral side
2) Space occupying lesion, increased intercranial pressure
What 3 nerves traverse the superior orbital fissure?
1) CN 3, Oculomotor n. (AO)
2) CN 4, Trochlear n. (SO)
3) CN 6, Abducens n. (LR)
1) What does the superior branch of CNIII (oculomotor) innervate?
2) What do the inferior branches of CNIII (oculomotor) innervate?
1) SR and levator palpebrae superioris m
2) MR, IR, IO, and presynaptic parasympathetic fibers to ciliary ganglion
What two arteries supply the orbit? What are these branches of?
1) Ophthalmic artery
-Br of internal carotid
-Central retinal artery (to neuronal layer of retina)
2) Infra-orbital artery
-Br of external carotid; contributes to orbital floor
1) What kind of vision loss does central retinal artery occlusion (CRAO) cause? Is it abrupt? Is it painful?
2) What usually causes it?
1) Acute, painless, vision loss, ipsilateral lesion
2) Temporal arteritis (autoimmune d/o); emboli from carotid stenosis
1) What kind of vision loss does central retinal venous occlusion (CRVO) cause? Is it abrupt? Is it painful?
2) What usually causes it?
3) Where can it extend to?
1) Less abrupt, painless, vision loss ipsilateral
2) Emboli or infection
3) Cavernous sinus
1) What is the primary blood supply to the eye?
2) What is the only supply to the neuronal layer of the retina?
3) What do the choroid vessels supply blood to?
4) Where do the veins of the eye drain?
1) Internal carotid via ophthalmic artery
2) Central artery of retina
3) External aspect of retina
4) Cavernous and pterygoid sinuses
1) When you look directly up, what muscles are being used? What cranial nerve(s)?
2) When you look directly down, what muscles are being used? What cranial nerve(s)?
1) Up: Superior rectus (CN3), inferior oblique (CN3) (both eyes)
2) Down: Inferior rectus (CN3), superior oblique (CN4) (both eyes)
Name an afferent pupillary light defect
“Marcus Gunn” pupil
Define presbyopia
Loss of accommodation
Define accommodation and what innervation is involved
Active process of changing shape of lens for near vision; CN III, parasympathetic postganglionic fibers
What are cataracts?
Clouding of the lens
