Exam3Lec4/5EyeandEar Flashcards by Daniella Andre

What is the orbit?

“eye socket” made up of 6 bones

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What are the 6 bones of the orbit?

Frontal
Sphenoud
Zygomatic
Maxillary
Lacrimal
Ethmoid

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What are the eyelid structures?

orbiularis oculi m.
Levator palpabrae superioris (LPS) m.
Inferior tarsal plate (tarsus)
Tarsal gland
Lacrimal grand

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What does the orbicularis oculi m. do?

closes eyelid

impt

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What does the levator palpabrae superioris (LPS) m. do and what is its innervation?

open eyelid
inn: oculomoter n. (CNIII=3)

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What does the inferior tarsal plate (tarsus) do?

gives eyelid strength

not high yield

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What does the tarsal gland do?

helps keep the eye moist

low yield

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What does the lacrimal gland do? What is its location and its release pathway?

secretes the fluid swept across the eye
Location: supero-lateral
Pathway: Punctum, lacrimal canaliculi, lacrimal sac, lacromcal duct

high yield

helps produce tears

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What are the external structures of the eye?

Sclera: whites of the eyes, continues w/ cornea
Cornea: transparent part of the eye, covers iris + pupil
Iris: eye color
Pupil: black hole w/in iris
Conjunctiva: internal lining of the eyelid, covers sclera

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What are the interal structures of they eye?

choroid: middle eye (vascular) layer
Retina: inner eye layer
Fovea (macula): area of greatest visual acuity
contains only cones, giving us color vision
Optic disk: blind spot (where optic n. enters)

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What can be seen on the “anterior” aspect of the eye?

Covered by the orbicularis oculi m (eyelid)
Contains the** trochlea**=cartilage on the frontal bone of the orbit (eye socket)
location: supero-medial
fxn: attachment site for the superior oblique m

contains brs from trigeminal n. (CNV-5)–> supraorbiral n. (V1) +supratrochelar n. (V1) + infraorbital n (V2)

-trochlea fxn and cadaver image is high yield
-note for the nerves, these are just housed in socket, and provied innervation to the orbit, not the muscles
-V1=opthalmic br
-V2: maxillary br

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What can be seen on the “superior” aspect of the eye?

Levator palpebrae superioris (LPS) m.: most sup.
Superior rectus m.: deep to LPS
Medial + Lateral rectus m.: inferior to the superior rectus
Superior Oblique m.: deep to superior rectus–> runs throough the trochlea

all the rectus muscles connect to a common tendinous ring
these are just to give us idea where they are so we can identify in the cadaver image

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What is the arterial suppy for the eye?

Internal carotid artery—> opthalmic artery (has 6 branches)

very low yield

only the scalp+ eye have arterial supply from the internal carotid artery, everything else is either external carotid or subclavian artery

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What are the 6 branches of the opthalmic artery?

1. Supraorbital art.
2. Supratrochlear art.
3. Lacrimal art.
4. Ethmoidal art.
5. Anterior + Posterior Ciliary art.
6. Doral Nasal art.

only 1 and 2 we talked about

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What innervates the eye?

Optic n. (CN II=2)
Oculomotor n. (CN III=3)
Trochlear n. (CN IV=4)
Abducens n. (CN VI =6)
Ciliary ganglia–>short ciliary n.
Long ciliary n.

the trigeminal n. (CN=5) gives off the opthalmic br (V1) which inn the eye orbit and NOT the actual eye muscles

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Optic n. (CN II=2)

sensory (sight)

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Oculomotor n. (CN III=3)

innervation to
superior eye=LPS +superior rectus m.
Inferior eye= medial rectus + inferior rectus + inferior oblique m

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Trochlear n. (CN IV=4)

innervation to superior oblique m.

note that damage to this (trochlear nerve palsy) can cause torticollis

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Abducens n. (CN VI =6)

innervation to lateral rectus m.

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Ciliary ganglia–>short ciliary n.

innervation to Ciliary body + iris
Provides sympathetic + parasympatheic inn

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Long ciliary n.

innervates cornea, iris, dilator pupillae
* provides symp inn to pupil
* provides sensory inn to cornea + iris

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What are the eye muscles?

Levator palpabrae superioris (LPS)
Superior oblique
Inferior oblique
Inferior rectus
Medial rectus
Lateral rectus

know all muscles, innervation, and action

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What is the innervation and action of LPS?

Inn: oculmotor n. (CN3=3) superior division
actions: elevation of superior eyelid

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What is the innervation and action of superior oblique?

Inn: trochelar n. (CN4)
actions: abduction + depression

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What is the innervation and action of inferior oblique?

Inn: oculomotor n. (CN 3) inferior division actions: **ab**duction + **elevation**

What is the innervation and action of superior rectus?

Inn: oculomotor n. (CN 3) superior division actions: **add**uction + **elevation**

What is the innervation and action of inferior rectus?

Inn: oculomotor n. (CN 3) inferior division actions: **add**uction + **depression**

What is the innervation and action of medial rectus?

Inn: oculomotor n. (CN 3) actions: **add**uction

What is the innervation and action of lateral rectus?

Inn: abducens n. (CN 6) actions: **abd**uction ## Footnote only rectus that abducts

The ear is separated into what three parts?

external ear, middle ear, inner ear

What is contained in the external ear?

auricle + external acoustic meatus ## Footnote no cadaver photos

How does the external ear send vibrations?

Send it to the tympanic mem, malleus, incus, stapes, oval window, cochlea

What is contained in the middle ear?

1. malleus (hammer)-> incus (anvil)-> stapes (stirrup) -bones of the middle ear magnify virbration (sound) 2. tympanic membrane: ear drum -splits into 2-> pars flaccida + pars tensa 3. Oval window: receives vibrations from stapes 4. Round window: stops vibrations from rebounding 5. Tensor Tympani m.: reduces/dampens vibration -inn: mandibular br. (trigeminal n. CN V-3) Location: petrous part of the temporal bone **has br of facial n. CN VII =7)--> chorda tympani** ## Footnote number 5, is a low yield muscle, most likely no cadaver photo facial nerve point is high yield, but no cadaver photo

What is contained in the inner ear?

* **Bony labyrinth** (w/ perilymph) & **Membranous** (w/ endolymoh) * Cochlea: hearing * Semicircular canals: motion + rotational sense | first point is high yield

What innervates the ear?

CN VII (7): facial n CNVIII(8): vestibulocochlear n ## Footnote both nerves travel in the internal acoustis meatus ( of the post cranial fossa)

What does CN VII (7): facial n. branch off to and travel?

brs, into chorda tympani--> travels through the tympanic membrane (ear drum)

What are the division of CN VIII (8): vestibulocochlear n?

* Vestibular division: for balance, gaze & acceleration * Cochlear division: for hearing ## Footnote very high yield

What is this arrow pointing to?