Eye and Eye Movements Flashcards
What bone is usually involved in a blow out fracture?
Maxillary bone part of the orbital wall (medially/inferiorly)
What movements of the pupil happen around the vertical axis, horizontal axis, and AP axis?
Vertical - ABduction/ADduction
Horizontal - Elevation/Depression
AP - Intorsion (medial rotation)/Extorsion (lateral rotation)
Where does the levator palpebrae superioris m attach?
Sphenoid bone to upper eyelid
What is the action and innervation of levator palpebrae superioris m?
Elevates eyelid and innervated by CN III
What muscle/nerve closes eye? What muscle/nerve opens eye?
Closes - orbicularis oculi m (CN VII)
Opens - levator palpebrae superioris m (CN III)
What innervates the superior oblique m?
CN IV (Trochlear n)
What innervates the lateral rectus m?
CN VI (Abducens n)
What muscles are elevators of the eye?
Inferior oblique m and superior rectus m
What muscles are depressors of the eye?
Superior oblique m and inferior rectus m
What is the tendinous ring?
Tendons of the rectus muscles
What nerves go through JUST the superior orbital fissure?
Frontal n, lacrimal n, trochlear n
What nerves go through the superior orbital fissure AND the tendinous ring?
Oculomotor n (superior and inferior divisions), nasociliary n, abducent n
What does the optic nerve travel through?
The optic canal AND the tendinous ring
What do sympathetic nerves that jump on the external carotid plexus do?
Salivary glands (dry/mucous secretions), sweat glands, constrict blood vessels
What do sympathetic nerves that jump on the internal carotid plexus do?
Dilate pupil and aid in keeping eyelid open (tarsus m)
What nerves make up the nerve of the pterygoid canal? What does this nerve do?
Deep petrosal n (sympathetic n) and greater petrosal n (parasympathetic n). Nerve goes to pterygopalatine ganglion and to blood vessels
What is Horner’s syndrome?
Damage to the superior cervical ganglion. Ptosis, anhydrosis, constricted pupil, flushing of skin (dilated blood vessels)
What do presynaptic parasympathetic nerves travel with? Where do they synapse?
Oculomotor n, ciliary ganglion
What do parasympathetic nerves do?
Constrict the pupil
What is trochlear n palsy?
Superior oblique m no longer works, lateral rotators don’t work so head tilts away from affected side. Also usually depresses eye so when looking down, one eye doesn’t move down and one does so you get diplopia
What is abducens palsy?
Cannot look laterally/abduct eye
What is oculomotor palsy?
Eye is down and out (only muscles left are superior oblique m and lateral rectus m), complete ptosis due to loss of levator palpebrae superioris m, pupil dilation due to loss of parasympathetic innervation to pupil
What two components does any reflex have?
A sensory and motor component
What is the pupillary light reflex?
A 4-neuron arch. Sensory component - optic n.
Motor component - parasympathetics traveling with CN III
What is the corneal reflex?
Sensory component - trigeminal V1
Motor component - facial n (closes eye with orbicularis oculi m)
What are the layers of the eyeball?
Fibrous layer - sclera and cornea
Vascular layer - choroid, ciliary body, iris
Inner layer - retina
What is the optic n surrounded by and what is contained within the nerve?
Dura mater, arachnoid mater, pia mater.
Central retinal v and a
What are the two conjunctiiva and where are they?
Palpebral conjunctiva lines innermost part of eyelid
Bulbar conjuncitva lines outermost part of eyeball
Where do the two types of conjunctiva come together
Superior conjunctional fornix
What is the difference between levator palpebrae superioris m and superior tarsal m?
LPS pulls eyelid up and is innervated by CN III
Superior tarsal m keeps eyelid up and is innervated by sympathetic nervous fibers
What is a subconjuncival hemorrhage?
Rupture of blood vessel between sclera and bulbar conjunctiva when abdominal pressure increases
What is complete vs partial ptosis?
Complete - LPS or CN III damage
Partial - tarsal m problem
What is papilledema?
Bulging optic disc caused by increased intracranial pressure
What are the anastamoses around the eye?
Supratrochlear a and angular a
Supraorbital a and superficial temporal a
Ethmoidal a and sphenopalatine a
Lacrimal a and middle meningeal a
Which important artery of the eye does not anastomose with anything?
Central retinal a
What is the clinical presentation of a central retinal vein occlusion?
Ketchup splotches on retina. Caused by hardening of central retinal a or hemorrhages
What is the clinical presentation of a central retinal artery occlusion?
Pale and red spot. Pale due to occluded artery, red spot is macula taht is supplied by the choroid. Can be caused by an embolism
What makes up the lacrimal apparatus?
Lacrimal gland (makes tears) Lacrimal canaliculi (two small straws that wick tears) Lacrimal sac (collects tears from lacrimal canaliculi) Nasolacrimal duct (drains lacrimal sac)
What is the pathway the facial nerve takes to get to the lacrimal gland?
Internal auditory meatus to petrous part of temporal bone
Through geniculate ganglion without synapsing
Exit through hiatus for greater petrosal n
Becomes greater petrosal n
Meets up w/ deep petrosal n (postsynaptic sympathetic)
Goes through pterygoid canal and becomes n of pterygoid canal
Synapses at pterygopalatine ganglion
Jumps onto zygomatic branch of V2
Jumps onto lacrimal n of V1 via communicating branch
Where is the anterior chamber?
Between cornea and iris
Where is the posterior chamber?
Between iris and lens/ciliary body
Where is the vitreous chamber?
Behind lens
What is the ciliary body?
Composed of ciliary m and ciliary processes. Innervated by parasymp of oculomotor n.
What are ciliary processes?
Secrete aqueous humor that fills anterior and posterior chambers
How does the aqueous humor flow?
From posterior chamber to pupil and around iris to anterior chamber, drains through Schlemm’s canal
What happens if Schlemm’s canal is blocked?
Increased intra-ocular pressure due to continued secretion of aqueous humor = glaucoma, can compress optic n
What is a hyphema?
Rupture of vessel in anterior chamber
What does the ciliary body do to the lens when it contracts?
Relaxes suspensory ligaments (zonular fibers) which allows lens to get rounder instead of flat (to see closer)
What makes up accommodation?
Convergence of eyes, pupil constriction, rounding of lens
