Anatomy Flashcards
How many bones make up the orbit?
7
Name the bones that make up the orbit…
zygomatic frontal sphenoid ethmoid maxilla nasal lacrimal
What part of the orbit is most vulnerable to injury?
orbital floor
What bones make up the orbital floor?
maxilla
zygomatic
nasal
What are the contents of the superior orbital fissure?
CN III, IV, V1 and VI
Superior ophthalmic vein
What cranial nerve passes through the inferior orbital fissure?
CN V2
What is the function of muller’s muscle?
assists eyelid elevation
What is the nerve supply of mullers muscle?
sympathetic
What muscle closes eyelids? and what nerve innervates it?
orbicularis oculi
CN VII
Name the syndrome caused by sympathetic injury to mullers muscle?
Horners syndrome
Is tear production stimulated by sympathetics or parasympathetics?
parasympathetics
What prevents the reflux of tears (lacrimation)?
Valve of Hasner
between inferior meatus and nasolacrimal duct
What nerve supplies the conjunctiva?
CN V1
Where does the lymph drainage of the conjunctiva go to?
Preauricular and submandibular lymph nodes
name the 3 layers of the eye…
Fibrous layer
Vascular layer
Neural layer
What makes up the fibrous layer?
sclera and cornea
what is the purpose of the sclera?
attachment sites for recti muscles
How many layers is the cornea made from?
5
What makes up the vascular layer?
choroid
ciliary body
iris
What is the function of the choroid?
supplies retina
What is the function of the ciliary body?
produces aqueous humour
adjusts of lens
What is the function of the iris?
protects retina
What makes up the neural layer?
retina
What types of cells are in the retina?
rods and cones
What is the name of the part of macula with the most rods/cones?
fovea
what is the name given to the central part of the retina?
macula
What is the anterior chamber of the eye?
in front of lens
contains aqueous humour
What is the posterior chamber of the eye?
behind lens
What is in the posterior cavity?
vitreous body
What muscle increases pupil diameter? and what innervates it?
dilator pupillae
sympathetic
What muscle decreases pupil diameter? and what innervates it?
sphincter pupillae
parasympathetic, CN III
What is the function of the ciliary muscles?
increase refractive power by constricting ciliary body, relaxing zonules, making lens more spherical
Name the 6 extraocular muscles?
lateral rectus inferior rectus superior rectus medial rectus superior oblique inferior oblique (4 rectus, 2 oblique)
What do the recti muscles do?
adduct
what do the oblique muscles do?
abduct
How does CN III palsy present?
eyes are down and out
dilated pupil
How does CN IV palsy present?
restricted eye movement when looking down and in
How does CN VI palsy present?
unable to move gaze laterally
What nerves give sensory innervation to the eye?
CN II
CN V1
What nerves give motor innervation to the eye?
CN III, IV, VI (rectus muscles) CN VII (orbicularis oculi)
What is the principle vascular supply to the eye?
ophthalmic artery
What does the central retinal artery supply?
inner 2/3rds of retina
What supplies the outer 1/3rd of the retina?
choroidal circulation
what is another name for the vascular layer of the eyeball?
uvea
What is the origin of the rectus muscles?
common tendinous ring
What is the optic disc?
the raised disc on the retina at the point of entry of the optic nerve, lacking visual receptors and so creating a blind spot
Which part of the orbit is most susceptible to blow out fractures?
medial wall and orbital floor
What is the direction of lacrimal fluid?
produced at lacrimal gland washes over eye medially drains through lacrimal puncta into lacrimal sac into nasolacrimal duct
What does parasympathetic activity on the ciliary body allow for?
thickens lens for near vision
what is another name for mullers muscle?
superior tarsus
What attaches the superior tarsus to the skin of eyelid?
tendon of levator palpebrae superioris
What becomes more “jelly-like” as we age?
vitreous humour
What nerve supplies the lateral rectus muscle?
CN VI
What nerve supplies the superior oblique muscle?
CN IV
What is the pneumonic to remember the cranial nerve innervation of the extraocular muscles?
LR6 SO4 AO3
