Ophth Anatomy Flashcards
uvea = __+__+__
choroid
ciliary body
iris
CNs associated with the eye =
II III IV V VI VII
hypermetropia =
need a __ lens to correct otherwise beams meet ___ relative to retina
long sighted
() = convex lens
posterior
myopia =
need __ lens to correct otherwise beams meet ___ relative to retina
short-sighted
)( = concave lens
anterior
astigmatism =
lens/cornea is rugby ball shaped rather than spherical
can cause blurred/distorted vision
presbyopia is due to ___
lens proteins stiffen and lose accomodation ability
red reflex can be reduced by __/___
retinoblastoma
cataracts
causes of ethmoid orbital plate # are usually ___ and cause a ___ # of the medial orbital wall
indirect
blow out #
3 bones that make up the orbital rim
maxillary (inf medial)
zygomatic (inf lateral)
frontal (sup)
palpebrae =
components =
eyelids outer skin conjunctiva trasal plate meibomian glands orbicularis oculi levator palpebrae superioris
thickened CT that maintains shape of eyelid
tarsal plate
gland in eyelid that secrete oily substance
meibomian glands
tears go __>___ across the cornea
drain to ___ > canaliculi > lacrimal sac > ____ > ___ of lateral nasal cavity wall
superolateral inferomedial puncta lacrimalia nasolacrimal duct inferior meatus
innervation of lacrimal gland =
CNVII
orbicularis nerve supply =
CNVII
Levator palpebrae superioris innervation =
CNIII
3 layers of the eyeball and their components =
outer fibrous (sclera and cornea) middle vascular pigmented (choroid, ciliary body, iris) inner nervous (retina)
two smooth muscles of the iris
sphincter pupillae
dilator pupillae
sphincter pupillae is arranged ____
used in ___
nerve control =
concentrically
bright light and accomodation to constrict the pupil
parasympathetic CNIII
dilator pupillae is arranged ___
used in __+__
nerve control =
radially
dim light and fright to dilate pupil
sympathetics from internal carotid plexus
point of best visual acutiy = ____
is a depression in the retina
fovea centralis in macula lutea
aqueous space in front of pupil =
anterior chamber
posterior chamber of aqueous humour lies between
pupil and lens
function of the superior rectus =
innervation =
test =
look up and in
CNIII
test = look out and then up
medial rectus function =
innervation =
test =
adduct eye
CNIII
adduct eye
inferior rectus function =
innervation =
test =
look down and in
CNIII
test = look out then down
lateral rectus function =
innervation =
test =
abduct the eye
CNVI
test = abduct eye
superior oblique function =
innervation =
test =
look down and out
CNIV
test = look in then down
inferior oblique function =
innervation =
test =
look up and out
CNIII
test = look in then up
CN_+++_ have parasympathetic fibres and so can supply glands
CN III, VII, IX, X
supraorbital nerve = a branch of ___
passes through the ____ of the ___ bone
CNV1
supraorbital foramen/notch of frontal bone
infraorbital nerve = a branch of ___
passes through ___ of __ bone
CNV2
infraorbital foramen of maxilla
site of lacrimal gland
superior and lateral to eyeball
Supports both eyes in the same vertical plane =
Suspensory ligament
Suspensory ligament is attached to ___ + ____
Zygoma
Lacrimal bone
If zygoma fracture then eye tends to ____ leading to diplopia
Rotate medially towards the orbital floor
General sensory areas of the face supplied by V1 (ophthalmic) =
Upper eyelid
Cornea
Conjunctivae
Root bridge. And tip of nose
General sensory areas of the face supplied by V2 (maxillary)
Lower eyelid
Maxillary skin
Nose ala
Upper lip
General sensory areas of the face supplied by V3 (mandibular)
Mandible and TMJ skin
General sensory to angle of mandible is supplied by
C2+3
Corneal/blink reflex:
Touch cornea>CN__>___ganglion>CN___>pons>CN__motor to ___ part of _____ >blink
V1 Trigeminal V VII Palpebral part of orbicularis oculi
Eyepatch is needed if have a ___ palsy as cant do motor part of blink reflex
CNVII
Sympathetics to head:
Presynaptic synapse at. ____ (releasing___) then post synaptic axon travels along ___ and release ___ at target organs
Superior cervical ganglion
ACh
I/ECA
NA
Presynaptic sympathetics of the head exit spinal cord at ____ spinal nerve
T1
Inferior cervical and 1st thoracic ganglion often fuse to form ____
Stellate ganglion
_____ from ____ carries the orbital sympathetics
Ophthalmic artery
ICA
CNIII passes through____ in the base of the skull
Superior orbital fissure
CN III synapses at ____ in the orbit to supply the eye
Ciliary ganglion
Superior branch of CNIII supplies ____ to which structures?
Somatic motor
Superior rectus
Levator palpebrae superioris
Inferior branch of CNIII supplies ____ to which structures?
Somatic motor
Medial inferior and lateral rectus
Parasympathetics to the eye come from which nerves
CNIII (inferior branch) VII IX X Sacral Spinal nerves Short ciliary nerve
CNVII parasympathetics synapse at ____ to supply the lacrimal gland and ____ to supply submandibular and sublingual glands
Pterygopalatine
Submandibular
Parasympathetics of CNIX synapse at ____ to supply the ___ salivary gland
Otic ganglion
Parotid
Types of fibres in the long ciliary nerve and its function
Sympathetic
Somatic sensory
First part of afferent limb of corneal reflex
Short ciliary nerve contains ___+__+___ fibres
Somatic sensory, parasymp and symp
Long and short ciliary nerves supply autonomic axons to control __+___
Pupil size
Refractive shape of the lens
Autonomic reflexes of the eye (6)
Maximum eyelid elevation (flight/fight) Pupillary light reflex Accomodation reflex Lacrimation Vestibulo-ocular Oculocardiac reflex
Vestibulo-ocular reflex involves which CNs
8
3
4
6
Oculocardiac reflex =
Which nerves?
Reflex bradycardia if tension of extraocular muscles or increased eye pressure
CNV1 + X
Effects of sympathetics on the eye = (4)
Emotional lacrimation
Eyes open wider
Pupils dilate
Focus on far objects
Parasympathetic effects on the eye = (4)
Reflex/cleaning lacrimation
Orbicularis oculi
Pupils constrict
Focus on near objects
In opening the eyes wider sympathetic post synaptic fibres reach the LPS from (4)
Superior cervical symp ganglion
Internal carotid nerve
Internal carotid plexus
Axons on ophthalmic artery and its branches
LPS type of muscle
Smooth and skeletal
Fixed and mobile insertions of the dilator pupillae =
Fixed - external edge of iris
Mobile - internal edge of iris
Non physiologically dilated pupil aka
Mydriatic pupil
Sphincter pupillae. Is around the ___ of the iris
Internal cicumference
Non physiologically constricted pupil aka
Component of ___ (pathology)
Miotic
Horners
Opiates cause a ___ pupil
Fixed pinpoint
Fixed dilated pupil (aka?) is a sign of _____
Blown pupil
CNIII palsy
Pupillary light reflex:
Special sensory afferent limb of reflex = ____ >____>bilateral _____
Ipsilateral CNII
Thalamus
CNIII motor limb
Pupillary light reflex causes a ___ and ____ reflex
Direct (stimulated eye)
Consensual
Pupillary light reflex involves___ neurons
____ pass via ipsilateral optic nerve to decussate at ____
Then synapse at _____
Next synapse is at ______ then to ___ who’s inferior division synapses at the _____ to ___ to sphincter pupillae
4 Retinal ganglion cells Optic chiasm Pretectal nucleus in midbrain Edinger Westphal nucleus CNIII Ciliary ganglion Short ciliary nerves
____ acts like a sphincter around circumference of ciliary body
Is responsible for____
Smooth ciliary muscle
Accomodation
____ connects lens to ciliary body
Suspensory ligament of the lens
Ciliary muscle:
____ in near vision (para/symp) ligament ____ and lens shape =
Contract
Parasympathetics
Relax
Spherical
Ciliary muscle:
___ nerve supply causes it to ____ in far vision, ligament ___ and lens shape =
Sympathetic
Relax
Tighten
Flattens
3 components to accomodation reflex to near
Nerve involved =
Bilateral pupil constriction
Bilateral convergence (medial rotation) of eyes
Bilateral lens relaxation
CNIII
Afferent for reflex tears and also the efferent
Afferent V1
Efferent VII parasympathetics
Parasympathetics to lacrimal:
___ nerve from CN VII>___ganglion > axons carried on ___ then ____
Greater petrosal nerve
Pterygopalatine
V2
V1
If the drainage of aqueous humour is blocked or it is overproduced =>___
Glaucoma
Causes of raised ICP
Head trauma Hydrocephalus Space occupying lesion Abscess Meningitis Haemorrhage
Monro-Kellie hypothesis
Total volume of blood, brain and CSF in cranial cavity is constant
Therefore if one increases the other two/one must decrease
Sunset sign -
Sign of -
Can see whites of the eyes above iris
Hydrocephalus
Thick and fibrous meninges
Outer/inner
Names of the two layers
Dura mater
Outer
Endosteal and meningeal
Outer to inner meninges
Dura mater
Arachnoid mater
Pia mater
Pia mater is how thick
Unicellularly
The different dura maters in the skull = (5)
Falx cerebri Diaphragma sellae Tentorium cerebelli Tentorial notch Falx cerebelli
Dura mater that splits two cerebrum hemispheres
Falx cerebri
Dura mater that splits to cerebellar hemispheres
Falx cerebelli
Dura mater superior to pituitary
Diaphragma sellae
Dura mater separating cerebrum from cerebellum
Tentorium cerebelli
If ICP is raised the brain may be forced into these two spaces
Foramen magnum
Tentorial notch in dura mater
Parts of the lateral ventricles (4)
Body
Ant/frontal horns
Occipital/posterior horns
Temporal/inferior horns
Visual problems associated with raised ICP
Transient blurred vision Diplopia Loss of vision Papilloedema Fixed dilated pupil
Why is a fixed dilated pupil an early sign of raised ICP?
CNIII para fibres that supply sphincter pupillae lie on the outside of the nerve and so are compressed first => unopposed action of dilator pupillae
Symptoms of papilloedema
Transient visual obscurations (greying out) Transient flickering Blurry Constriction of visual field Decreased colour perception
Grade 1 papilloedema =
C shaped halo blurring disc edge
Stage 2 papilloedema
Circumferential halo with blurred edges
Stage 3 papilloedema
Vessels on edge of disc disappear
Stage 4 papilloedema
Loss of major blood vessels on the disc
Stage 5 papilloedema
Extremely blurred disc and total/partial obscuration of vessels on disc
Sensory supply of dura mater =
CNV
Level a lumbar puncture is taken at
IV disc L3/4 or L4/5
Subarachnoid space ends here in spinal column
S2
Signs of CNIII damage
Lose pupillary light reflex
Ptosis
Eye turns inferolaterally
Signs of CNIV damage
Inferior oblique unopposed so cant move eye inferomedially
Diplopia on down gaze
Signs of CNVI damage
Cant move eye laterally in horizontal plane
3 cardinal signs of Horners syndrome
Ptosis
Miosis
Anhydrosis
Causes of follicles on lower eyelid -
Viral
Chlamydia
Down and out eye with ptosis =
Complete CNIII palsy
3 things to consider when describing the appearance of an optic disc
Cup colour contour
Rough diameter of the iris
11-12mm
Eye rough diameter
24mm
Where the eye meets the medial epithelium =
Plica semilunaris
2 muscles involved in the eye opening
Lps
Mullers muscle
In horners if this muscle is affected (as it has sympathetic control) it causes ptosis
Mullers muscle
Orbitsl septum originates from ___, blends with ___ superiorly and inserts into ___ inferiorly
Orbital periosteum
LPS tendon
Tarsal plate
Cellulitis in front and behind orbital septum are called?
Preseptal
Orbital (sight threatening)
Layers of cornea deep to superficial
Endothelium Descemet's membrane Stroma Bowmans membrane Epithelium
Part of cornea that contains regularly spaced collagen fibres
Stroma
Function of the endothelium in the cornea
Maintains transparency by pumping fluid out of the stroma
Lens is attached to ciliary body by ___
Zonules
___ in tension of zonules allows for near focus
Decrease
Contraction of ciliary muscle causes the tension of the zonules to ___
Decrease
CNIII is vulnerable to ____ aneurysms at it lies close to it
Posterior communicating artery
Why does a lesion of the CNIV cause a palsy on the contralateral side muscle?
Attaches to brain at pons and crosses over
Position of the trochlear nucleus of CNIV
Inferior to cerebral aqueduct
CNIv enters eye via __
Superior orbital fissure
Palsies of CNVI are usually caused by ___
Raised ICP stretching it
CNVI passes through the middle of ____
Nucleus is in the ____
Cavernous sinus
Pons
Rectus muscles all arise from the ____ which is also attached to the ____ therefore optic neuritis often causes____
Common tendinous ring
Optic nerve sheath
Pain on eye movements
Strongest and thickest rectus muscle
Medial
Blowout fracture typically entraps the____
Inferior rectus
Epithelium that makes up the retina
Pigmented cuboidal
Blind spot lies ____ in the visual field
15degrees temporally
Vascular tunic that supplies the outer retinal layer -
Choroid
Superior ophthalmic vein leaves eye via ___ and drains to ____
Superior orbital fissure
Cavernous sinus
Long and short ciliary nerves become part of _____
CNVs nasociliary nerve
Retina has no ___ sensation
Pain
Thinnest orbital wall
Medial
Orbital wall most vulnerable to blunt trauma
Inferior
Supraorbital nerve and vessels pass through the ___
Supraorbital notch
Blowout fractures usually cause pain on ___
Upgaze