Eye And Orbit Flashcards
Cornea
Transparent anterior 1/6 of outer coat of eyeball
Iris
Colored diaphragm seen cornea
Pupil
Aperture at center of iris
Sclera
Whitish opaque 5/6 of the outer coat of eyeball
Lavator palpebrae
Action and innervation
Elevates upper eyelid, CN III
Which nerve opens eye and which close it
3 opens 7 closes
Lacrimal glands
Innervated by which system and nerve
PNS- 7
SNS from superior cervical ganglion
Nasolacrimal duct
Does what
Conveys lacrimal fluid to nasal cavity
What covers sclera and anterior palpebral surface and keeps contacts from going back into orbit
Conjunctiva
Sphincter pupillae
Action
Stimulated by what
Role in which syndrome
Constricts or contracts pupil- miosis
PNS
Horners
Dilator pupillae
Stimulated by what
Action
SNS
Dilates pupil
Retina
Role in what
Light reception
Optic disc
What it transmits
Sensory fibers and vessels conveyed by CN II enter and radiate to eyeball
Macula
Role and what it has
Area of retina with specialized photoreceptor cone cells
Acuity of vision
Rod cells
Cone cells
Transmit light to brain
Visual acuity
Most refraction produced by what
Cornea
What fine tunes the focus of near or far objects on the retina
Convexity of the lens
___ muscle changes the shape of the lens (___)
Ciliary, shape
Ciliary is ___ in absence of nerve stim. ___ fibers under tension. Lens is ___ ___ to refract light for __ vision
Relaxed, zonular
Stretched thin, distant
PNS Stim causes ciliary muscle to ___. Zonular fibers ___. Lens becomes ___ to refract light for ___ vision.
Contract, relax
Thicker, near
All 3 extraocular muscles of orbit exit skull via
Superior orbital fissure
Nerve associated with lateral rectus
Abducens VI
Nerve assoc with superior oblique
Trochlear IV
Nerve assoc with superior rectus, medial rectus, inferior rectus, and inferior oblique
III oculomotor
Oculomotor controls which EOM
Sup rectus, med rectus, inf rectus, inf oblique.
Which nerve innervates levator palpebrae superioris
CN III
Rectus muscles have ___ attachment. Name 4
Anterior
Superior, inferior, lateral, medial
Oblique muscles have __ attachment
Posterior
Orbits are ___ in shape. Base is __ __. Apex is at __ __.
Pyramidal
Orbital margin
Optic canal
Eye movements: vertical axis: __ and __. Horizontal axis: ___, __ and __, __ and __. Anterior/posterior axis: __ __ and __ __
Left and right
Adductors, medial and lateral, elevators and depressors
Medial rotation and lateral rotation (intorsion and extorsion)
Muscles of extortion
Inferior oblique and inferior rectus
Muscles of intorsion
Superior oblique and superior rectus
Primary elevator
Superior rectus
Primary depressor
Inferior rectus
Ptosis caused by loss of what
Levator palpebrae superioris, CN III
Cause of pupil abducted and direction inferiorly (down and out)
CN III, unopposed actions of lateral rectus and superior oblique
What causes no pupillary reflex in affected eye
CN III, interruption of PNS fibers to sphincter of iris, leaves dilator pupillae unopposed
What causes no accommodation of lens
Cns III, interruption of PNS fibers causing paralysis of ciliary muscle
2 movements CN III doesnt do
Down and out and lateral movement
Lesion of CN III cant look ___ and ___, unopposed actions of what
Up and in, LR or SO
In CN IV lesion affected eye cant be directed ___, results in ___ when looking ___
Inferolaterally, diploplia, down
Diploplia: ___ ___ helps __ __ in the depressing eye. In the affected eye gaze directed ___ than unaffected eye
Inferior rectus, superior oblique
Differently
CN IV lesion can be partially corrected by tilting head __ and to __ of normal eye
Anteriorly and to side
CN VI palsy leads to paralysis of __ __ and produces __ deviation of eye
Lateral rectus, medial deviation
CN VI palsy: ___ present in all directions except when gazing to the __ __ the lesion
Diploplia, side opposite
At optic chiasm ___ fibers continue but __ fibers cross
Temporal, nasal
Fibers from __ half of each retina decussate in chiasm to join uncrossed fibers from __ half of retina to form __ __
Nasal, temporal, optic tract
Crossing over of fibers is required for ___ vision, allows for __ of field
Binocular, depth
Fibers from right half of both retinas form __ __ __
Right optic tract
Fibers from __ __ of both __ form left optic tract
Left half, retinas
4 visual fields
Left, right, nasal, temporal
Anopsia= \_\_\_\_ Bi= involves what
Blindness
Left and right visual fields
Involves which field when loss:
Nasal
Temporal
Nasal visual field
Temporal visual field
Involves which field when loss:
Hemi
Homonymous
Half of each visual field
Same field of vision in each eye (right/left)
Blindness of ipsilateral eye=
Right or left eye anopsia
Nasal hemianopsia caused by what
Calcification or aneurysm of internal carotid artery
Bitemporal hemianopsia caused by what and affects what
Commonly pituitary tumors, both eyes
Direct response to light
Ipsilateral pupil constricts
Consensual response to light
Contralateral pupil constricts
Pupillary light response:
Afferrent: cn __, __ eye
Efferent: cn ___, __ eye
II, ipsilateral
III, both eyes
Corneal reflex
Afferrent- cn __
Efferent- cn __
V1
VII
Preganglionic PNS fibers to eyeball are cn __. Postganglionic fibers emerge via __ __ __
III, short ciliary nerves
Pns innervation: \_\_\_ pupil (\_\_\_) and \_\_ lens of eye (\_\_)
Constricts, sphincter
Accommodates, ciliary
Pupillary light reflex: __ pathway by __ nerve. Efferent by CN __
Afferrent, optic
Efferent, III
Superior cervical ganglia is __ and is present in ___. Blood supply usually from __ __
Large, everyone
Internal carotid
Postganglionic sns fibers to eyeball are from __ ganglia via __ __ plexus
Cervical
Internal carotid
Sns innervation of eye __ pupil through __ __
Dilates, dilator pupillae
Horner syndrome: caused by __ of __ __
Manifestations: a sense of __ __ stim
Interruption of cervical sns trunk
Ipsilateral sympathetic
Signs of horner syndrome
Ptosis, anydrosis, Miosis, and vasodilation (heat and red skin)
If __ __ and __ __ muscles affected cant elevate eyelid
Superior tarsal and levator palpebrae
Most of blood supply to eye comes from __ artery. Supplies all of eyeball and branches to __ cavity (__ and __ __ arteries)
Ophthalmic, nasal, ant and post ethmoidal
Venous return of eye through __ vein mainly
__, __ __ veins have anastomoses
Facial
Supraorbital, inf ophthalmic
Cn II jobs: sensory __. __ limb of __ __ reflex
Vision. Afferrent, pupillary light
CN III func: motor to eye __ of __ ocular muscles and __ __ __
4 of 6, levator palpebrae superioris
Cn III: __ limb of __ __ reflex. Carries __ __ fibers to __ ganglion
Efferent, pupillary light
Preganglionic pns, ciliary
Trochlear nerve function: __ to __ __
Motor to superior oblique
Opthalmic nerve v1 func: __ to eye including what
Lacrimal gland, superior conjunctiva, external cutaneous structures, nasal cavity, and 3 sinuses (frontal, sphenoidal, ethmoid)
Opthalmic nerve V1: __ limb of __ reflex. Conveys __ fibers from __ ganglion to __
Afferrent, corneal
Autonomic, ciliary iris
Maxillary nerve V2: __ to __ __. Conveys __ fibers from __ ganglion to __ __
Sensory, inferior conjunctiva
Autonomic, pterygopalatine, lacrimal glands
Abducens nerve function: __ to __ __
Motor, lateral rectus
Facial nerve function: __ limb of __ reflex. Carries __ __ fibers to __ ganglion
Afferrent, corneal
Preganglionic pns, pterygopalatine
