Eye Anatomy Flashcards
What cranial nerve innervates the superior oblique muscle?
Trochlear nerve- CN IV
What is the action of the medial rectus on the eyeball?
When contracting, each medial rectus muscle adducts the eyeball
How many muscles does the abducens nerve innervate and what are/is their/its name
Lateral rectus muscle
Define diplopia
Double vision
How many of the extraocular muscles insert onto the sclera?
6
Why are the rectus muscles called the rectus muscles?
Because they are very straight and rectus means straight in old language
What is the mnemonic to remember the innervation of the extraocular muscles
LR6 SO4 AO3
How many muscles are involved in raising the upper eyelid? Can you name them?
2 muscles, the Levator Palpebrae Superiorus and superior tarsal muscle (but the superior tarsal muscle can just be seen as a part of the LPS)
Which extraocular muscle’s tendon passes through the trochlea?
Superior Oblique
What nerve innervates the LPS
Oculomotor CN III
Which nervous system controls Muller’s muscle?
Sympathetic
Which muscle closes the eyelid? And what nerve innervates this muscle?
Orbicularis oculi
CN VII
Explain accomodation:
what are the respective fissures that CN III, CN IV and CNVI pass through
CN III= Superior Orbital fissure
CN IV= Superior orbital fissure
CN VI= Superior orbital fissure
Which nerves do all parasympathetic axons leave the CNS via
CN III, CN VI, CN IX, CN X
Which artery carries sympathetic axons into the orbit
Internal carotid
What muscle controls the shape of the lens?
Orbicularis oculi
Which nerve innervates the orbicularis oculi?
CN VII (facial nerve) because it is a muscle of facial expression
What is another name for the superior tarsal muscle?
Muller’s muscle
Which 2 muscles control the iris size?
Sphinctor pupillae- decreases pupil size, CN III
Dilator Pupillae- increases pupil size, sympathetic nervous system
What type of vision occurs when the ciliary muscles contract?
Close vision
Because when these contract this loosens the zonular fibers increasing the convexity of the lens
