Orbit Flashcards
___ bones make up the orbit
7
Describe the orbital margin
- Widest aspect of orbit
- On frontal aspect
- Bounded by frontal bone superiorly, zygomatic bone laterally & inferiorly, & maxilla inferiorly & medially
- Made of 3 bones
Describe the apex of the orbit
Tip & posterior aspect of orbit
Fat under your eye is called
Periorbital fat
Label
- Frontal
- Zygomatic
- Maxilla
- Ethmoid
- Sphenoid
- Lacrimal
- Palatine
Label
- Zygomatic
- Periorbita
- Nasal Cavity
4, Ethmoid - Sphenoid
Label
- Superior orbital foramen
- Optic canal
- Superior orbital fissure
- Inferior orbital fissure
- Infraorbital foramen
What runs through the optic canal?
Optic nerve (CN II)
Ophthalmic artery
What runs through the superior orbital fissure?
Oculomotor (CN III)
Trochlear (CN IV)
Ophthalmic branch of trigeminal (CN V1)
Abducens (CN VI)
Ophthalmic vein, sympathetic fibers
What runs through the inferior orbital fissure?
Infraorbital nerve (CN V2)
Infraorbital artery
How many extraocular muscles do we have?
6
Label
- Superior rectus m
- superior oblique m
- superior levator palpebrae m
- Inferior rectus m
- medial rectus m
- lateral rectus m
- inferior oblique m
Label
- Trochlea
- Superior oblique
- Medial rectus
- Inferior rectus
- Inferior oblique
- Lateral rectus
- superior rectus
Function of the tarsal muscle
- Helps keep the eye open
- Helps lubricate eyes
- Provides sympathetic innervation via oculomotor n. In cavernous sinus & superior orbital fissure
- Helps maintain position of the eyeball
Define lacrimation
process of producing tears
Describe the lacrimal canaliculi
Allows excess fluid to move in, down the lacrimal sac, to nasolacrimal duct & drain under inferior nasal concha
What makes up the lacrimal apparatus
Lacrimal canaliculi
nasolacrimal duct
lacrimal gland
inferior nasal concha
nasal cavity
lacrimal sac
Label
- Lacrimal gland
- Inferior nasal concha
- Nasal cavity
- Lacrimal canaliculi
- Lacrimal sac
- Nasolacrimal duct
Special sensory for the orbit is by
Optic nerve (CN II)
General sensory for the orbit is by the Ophthalmic branch of trigeminal. What are the branches?
Lacrimal n., frontal n., nasociliary n.
Motor innervation for the orbit is provided by what 3 CN
CN III, IV, & VI
What does the Oculomotor (CN III) innervate
Levator palpebrae superioris
Superior rectus
Medial rectus
Inferior rectus
Inferior oblique
What does the trochlear n innervate?
Superior oblique
What does abducens n innervate?
Lateral rectus
Label
- supraorbital n
- lacrimal n
- ophthalmic n
- Trigeminal ganglion
- cavernous sinus
- trochlear n
- frontal n
- infratrochlear n
Label
- long ciliary n
- short ciliary n
- ciliary ganglion
- abducens n
- oculomotor n
- maxillary n (CN V2)
- trigeminal ganglion
- nasociliary n
- posterior ethmoid n
- anterior ethmoid n
- infratrochlear n
Label
- lacrimal n
- opthalmic n
- maxillary n
- rotundum opening
- pterygopalatine ganglion
- zygomatic n
- zygomaticotemporal n
- communicating branch
- lacrimal gland
Parasympathetic innervation to the orbit. What’s their function & muscle involved?
Ciliary ganglion
Preganglionic via CN III
Postganglionic in short ciliary
pupil constriction
Contains the sphincter papillae muscle
Sympathetic innervation to the orbit. What’s their function & muscle involved?
Superior cervical ganglion
Internal carotid plexus
It comes in along CN V1 & its branches
pupil dilation
contains dilator papillae muscle & tarsal muscle
the lacrimal gland provides secretomotor innervation via
CN VII
Label
- supratrochlear a
- anterior ethmoidal a
- posterior ethmoidal a
- central retinal a
- ophthalmic a
- ciliary a
- lacrimal a
- supraorbital a
Label
- Ciliary body
- iris
- pupil
- cornea
- lens
- suspensory ligament
- optic nerve
- optic disc
- fovea centralis
- retina
- choroid
- sclera
retina has a lot of
photoreceptors
Describe rod & cone cells
Rod cells: light sensitive, no color, seen in peripheral retina
Cone cells: color sensitive, minor light, concentrated in fovea centralis
Describe the fovea
center of the retina
- highest area of visual acuity
What are the intraocular muscles. do they provide parasympathetic or sympathetic?
Sphincter pupillae muscle (parasympathetic)
Dilator pupillae muscle (sympathetic)
Ciliary muscles (parasympathetic)
Define hypotropia, hypertropia, exotropia & esotropia
Hypotropia - 1 eye turns down
Hypertropia - 1 eye turns up
Exotropia - 1 eye turns out
Esotropia - 1 eye turns in
Define cataracts
problems w/ light focus due to cell growth, deposits, or protein changes in the lens
Define glaucoma
if the vitreous pressure is too high, optic nerve becomes damaged
Define aged-related macular degeneration
if the retina fails
Define astigmatism
if the cornea is abnormally curved
Horner’s syndrome is damage to the ___. What 4 things need to be damaged & define them
Sympathetic trunk
Ptosis - eyelid drooping
Myosis - constricted pupil
Anhidrosis - poor sweating
Enophthalmos - sunken eye
