Anatomy of the Orbit Flashcards
What bones make up the oribtal rim?
maxilla; zygoma; frontal
What additional bones make up the floor of the orbit?
ethmoid; lacrimal; sphenoid
What is found in the sphenoid in the floor of the orbit?
the superior and inferior orbital fissures and the optic canal
What are the bones most likeely to # in the orbit?
ethmoid and maxillary plate
What does the eyelid form that curves onto the eyeball?
inner conjunctiva
What is the tarsal plate?
slightly thickened area of connective tissue within the eyelid that contains tarsal glands
What is the longitudinal muscle of the eyelid?
levator palpebrae superious
What nerve supplies levator palpebrae superious
oculomotor
How do tears travel across the cornea?
from superolateral to inferomedial
What are the holes that tears flow into?
puncta lacrimalia
Where do tears go once through the puncta lacrimalia?
canaliculi into the lacrimal sac–lacrimal duct
What do tears drain into in the nose?
inferior meatus of the lateral wall
What are the CN with parasympathetic innervation?
III, VII, IX and X
What nerve supplies the lacrimal gland?
CNVII
What are the 3 layers of the eyeball?
outer fibrous; middle vascular pigmented; inner nervous
What makes up the outer fibrous layer of the eyeball?
sclera and cornea
What makes up the middle vascular pigmented layer of the eyeball?
choroid; ciliar body and iris
What makes up the inner nervous layer of the eyeball?
retina
What joins the ciliary body to the lens?
suspensory ligament of lens
What happens when the ciliary muscles are relaxed?
lens doesnt let much light in
What happens when the ciliary muscles are contracted?
the lend becomes fatter and lets more light in
What does the iris consist of?
smooth muscle fibres
What are the 2 muscles that the iris has?
sphincter pupillae and dilator pupillae
How are the sphincter pupillae muscle fibres arranged?
concentric
How are the dilator pupillae muscle fibres arranged?
radial
What is the innervation to the sphincter pupillae muscle?
CN III- parasympathetic
What is the innervation to dilator pupillae?
sympathetic supply- internal carotid plexus
What is the area of the retina that allows the most focused vision?
macula lutea with fovea centralis
What are the 6 extrinsic muscles of the eye?
superior and inferior obliques; superior, inferior, medial and lateral rectus muscles and lecator palpebrae supeiroris
What does the superior rectus do?
up and in
What does the inferior rectus do?
depresses and in
What does the lateral rectus do?
abducts the eye
Waht does the medial rectus do?
adducts the eye
What is the supply to most of the muscles of the eye?
CNIII
What nerve supplies lateral rectus?
abducens
What nerve supplies superior oblique?
trochlear nerve
What does the superior oblique pass around?
the trochlea (pulley)
What does inferior oblique do?
up and out
What does superior oblique do?
down and out
How is superior rectus tested?
up and out
How is inferior rectur tested?
down and out
How is superior oblique test?
down and in
How is inferior oblique tested?
up and in
What makes up the inferolateral oribtal margin?
zygoma
Waht is ptosis?
droopy eyelid
