Orbit I Flashcards
7 bones make up the orbit. Name the one not listed
Palatine
Identify “a” and “b”
- a: superior orbital fissure
- b: inferior orbital fissure
Identify “c”
optic canal
Identify green and yellow arrows
Green: Infraorbital foramen
Yellow: Supraorbital foramen
Identify blue arrow
nasolacrimal groove
Identify “a” and “b”
- “a” Superior tarsal plate
- “b” Inferior tarsal plate
Identify c
c: orbital septum
Identify arrow
medial and lateral palpebral ligaments
Identify arrows
green: superior tarsal plate
red: orbital septum
Identify the green box and green arrows
- green box: Conjunctival sac
- green arrow: Conjunctival fornices
Identify red and blue arrows
red: bulbar conjunctiva
blue: palpebral conjunctiva
Where is the lacrimal gland located
superolateral region of the orbit
List where the fluid from the lacrimal gland goes once it is in the eyeball
- lacrimal puncta
- lacrimal canaliculi
- lacrimal sac
- nasolacrimal duct
Parasympathetic innervation to the lacrimal gland is
- initiated at what cranial nerve?
- where does it synapse?
- How does the information from the ganglion get to the lacrimal gland: New pathway
CN VII -> Greater petrosal n. -> N. to pterygoid canal -> Pterygopalatine galgion (SYNAPSE) -> branches to lacrimal gland
Sympathetic innervation to lacrimal gland
follows parasympathetic innervation
Former pathway of parasympathetic innervation to lacrimal gland
CN VII -> Greater petrosal n. -> N. to pterygoid canal -> Pterygopalatine plexus (SYNAPSE) -> zygomatic branch of (CN V2) -> communicating branch of ophthalmic nerve (CN V1) -> Lacrimal nerve to gland
identify purple and brown
purple: cornea
Brown: Sclera
Identify blue and red
blue: choroid
red: retina
identify orange
ciliary body
Identify green and yellow
green: Fovea: strongest acuity
yellow: optic disc: blind spot
What muscle is responsible for constricting the pupil? What innervation makes it contract?
Sphincter pupillae
- parasympathetic
What muscle dilates the pupil? What innervation makes muscle contract
Dilator pupillae
- sympathetic innervation
The cililary muscle contract under what innervation? What happens when it contracts?
paraympathetic
- When muscle contracts; it moves toward the lens and the suspensory ligaments of the lens relax, causing the lens to change shape (more spherical) allowing lens to refract light for near vision
- Accommodation: close focus
List Pathway of light
- cornea
- iris -> pupil
- lens
- fovea centralis
- optical axis
The medial aspect of the eye gains information from what field?
Lateral
Damage to the left optic tract would present with what vision loss
nerves of the orbit are supplied by what nerve
Ophthalmic nerve (CN V1)
Name the termianl branches of the ophthalmic nerve (CN V1)
- supraorbital
- supratrochlear
- Lacrimal
- external nasal
- Infratrochlear
Branches of the opthalmic artery (branch of the internal carotid)
- central artery of retina
- lacrimal artery
- ciliary arteries
- supraorbital artery
- ethmoidal arteries
- dorsal nasal artery
Venous drainage from eye leaves via what 2 main branches
superior ophthalmic vein
inferior ophthalmic vein
Sympathetic innervation to eye
preganglionic axons travel sympathetic chain -> superior cervical ganglion (synapse) -> Postganglion axons follow arteries (internal carotid plexus) -> joing ciliary nerves entering eyeball
Parasympathtics to eyeball
preganglionic axons begin on inferior division of oculomotor (CN III) -> Ciliary ganglion (synapse) -> Postganglionic axons hitchhike on the short ciliary branches of the ophthalmic (CN V1)
pupillary light reflex
increase in light in one eye will result in pupillary constriction of both eyes
- Sensory: CN II
- Motor: CN III
Accommodation reflex
focus on close objects (change in lens shape) causes pupillary contraction
- Sensory: CN II
- Motor CN III
Corneal blink reflex
Contract with the cornea causes blinking
- sensory: CN V1
- Motor: CN VII
