Orbit Flashcards
What is the most superficial muscle of the orbit? What is its nerve supply?
- Orbicularis Oculi
- CN VII
What are the two portions of the Orbicularis Oculi?
- palbebral portion (inner)
- Outer orbital portion (outer)
What are the layers of the eyelid starting with the skin?
- skin
- orbicularis oculi (palpebral)
- Tarsal plate
- Glands
- Palpebral Conjunctiva
What is Ptosis?
- drooping of the eyelid
- from loss of sympathetic innervation to the eyelid
Complete closure of the eye = damage to somatic fibers
What is mydriasis?
-dilation of the pupil
What nerve innervates the superior oblique?
Trochlear nerve
What nerve innervates the lateral rectus?
Abducens
What nerve innervates all of the eye muscles except for the superior oblique and lateral rectus?
-Occulomotor
Which cranial nerves contain parasympathetics?
3, 7, 9, 10
What is the function of the lacrimal branch of V1?
sensory to the lateral orbit
Which artery supplies the retina?
- central artery of the retina (inner 2/3)
- choroidal vaculature (outer 1/3)
What movement does orbicularis oculi perform?
-light blinking closure of the eye
What happens to the eyelid on the side of a facial nerve lesion?
-can’t close eye
What does the levator palpebrae superioris attach to in the eye lid?
-the superior tarsal plate
What is the innervation to levator palpebrae supeiroris?
- CN III (striated muscle)
- sympathetics from superior cervical ganglion (smooth muscle)
What are the symptoms of a lesion to CN III?
- completely closed eyelid
- mydriasis
- lateral rotation of the globe
Where is the lacrimal gland located in relation to the eye?
-superior and lateral of the globe
What fibers are contained within the short ciliary nerve?
- general sensory fibers from V1
- postsynaptic parasympathetic from ciliary ganglion (CNIII) = pupil constriction & accomodation
- postsynaptic sympathetic fibers from carotid plexus
What fibers are contained within the long ciliary nerve?
- General sensory from V1
- postsynaptic fibers from superior cervical ganglion via carotid plexus
What’s the first thing to think about when glen mentions the short ciliary nerve?
-parasympathetics from ciliary ganglion that control pupil constriction & accomodation
On which sides of the optic nerve do the long and short ciliary nerves run?
Long = medial side
Short = lateral side
