Lecture 12: Eye and Eye Movements Flashcards Preview

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Flashcards in Lecture 12: Eye and Eye Movements Deck (61)
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1

What structures exit the Optic Canal?

CN II

Opthalmic Artery

2

What structures pass through the Inferior Orbital Fissure?

Maxillary Nerve --> Infraorbital Nerve

Zygomatic Nerve (CN V2)

Infraorbital Artery

3

In comparision with the orbit, where are these sinuses located?

Frontal

Ethmoid 

Maxillary

Sphenoid

  • Frontal: superior and medial
  • Ethmoid: medial
  • Maxillary: inferior
  • Sphenoid: posterior 

4

What can cause optic neuritis?

Chronic infections in the ethmoid sinus that erodes into the orbit 

5

What bone of the orbit is normally involved in an orbital blowout fracture?

Maxillary Bone

-Inferior to orbit 

6

What are some consequences of an orbital blowout fracture?

  • Diplopia (eyes not aligned)
  • Globe ptosis (eyeball falling through orbit)
    • Eye prolapses into maxillary sinus (if inferior bone breaks)
    • Eye prolapses into ethmoid sinus (if medial wall breaks)
  • Exophthalmos (protrusion of eyeball) 

7

What is the movement of the eyeball around the vertical, horizontal, and AP axis?

Vertical Axis

  • Abduction
  • Adduction

Horizontal Axis

  • Elevation
  • Depression

AP Axis

  • Intorsion (medial rotation)
  • Extorsion (Lateral rotation)

8

What extra-ocular muscles abduct the eyeball?

Superior Oblique Muscle

Inferior Oblique Muscle

Lateral Rectus Muscle

9

What extra-ocular muscles adduct the eyeball?

Superior Rectus Muscle

Inferior Rectus Muscle

Medial Rectus Muscle

10

What extra-ocular muscles are involved in bilateral eyeball depression?

Superior Oblique Muscle

Inferior Rectus Muscle

11

What extra-ocular muscles are involved in bilateral eyeball elevation?

Superior Rectus Muscle

Inferior Oblique Muscle

12

How do you test exta-ocular eye muscles?

How do you test Superior Rectus, Inferior Rectus, Superior Oblique, and Inferior Oblique Muscles?

Trap an individual muscle and test its functional pair.

Basically do the opposite of its normal function

  • Superior Rectus: Trap Inferior Oblique
  • Inferior Rectus: Trap Superior Oblique
  • Superior Oblique: Trap Inferior Rectus
  • Inferior Oblique: Trap Superior Rectus

13

What structures go through the Cavernous Sinus?

  • Oculomotor Nerve
  • Trochlear Nerve
  • Trigeminal Nerve
    • Ophthalmic Nerve
    • Maxillary Nerve
  • Abducens Nerve
  • Internal Carotid ARtery

14

What are branches of the Ophthalmic Nerve?

  • Tentorial Nerve
  • Lacrimal Nerve
    • General sensation to lacrimal gland
    • Parasympathetic innervation via Greater Petrosal Nerve (from CN VII) 
  • Frontal Nerve
    • Supratrochlear Nerve (medial)
    • Supraorbital Nerve (lateral)
  • Nasociliary Nerve 

15

What are branches of the Nasociliary Nerve?

  • Anterior and Posterior Ethmoidal Nerve
    • Nasal Cavity
  • Long Ciliary Nerve (goes to cornea)
    • Sensory
    • Sympathetic
  • Short Ciliary Nerve (comes off ciliary ganglion)
    • Parasympathetic to iris and ciliary body
    • Sympathetic 
    • Infratrochlear Nerve

16

What does the superior and inferior branches of the Oculomotor Nerve innervate?

Superior

  • Levator Palpebrae Superioris Muscle
  • Superior Rectus Muscle

Inferior

  • Inferior Rectus Muscle
  • Inferior Oblique Muscle
  • Medial Rectus Muscle

17

What nerves pass through the superior orbital fissure?

  • CN II: Optic Nerve
  • CN III: Oculomotor Nerve
  • CN IV: Trochlear Nerve
  • CN V1: Ophthalmic Nerve
  • CN VI: Abducens Nerve

 

18

What nerves pass through the common tendinous ring of the orbit?

  • CN II: Optic Nerve
  • CN III: Superior/Inferior divisions of Oculomotor Nerve
  • CN V1: Nasociliary Nerve
  • CN VI: Abducens Nerve

Common Tendinous Ring is made up of Rectus muscles

19

How does sympathetic innveration work with the eye muscles?

What are its actions?

Postganglioninc Sympathetic fibers arise from Superior Cervical Ganglion

  • Will travel with Internal or External Carotid Plexus

Actions

  • Deep Petrosal Nerve: constrict blood vessels 
  • Innervates Levator Papebrae Suprerioris to open eye
    • Oculomotor Nerve
  • Innervates Tarsal Muscles to keep eye opens
  • Innverates Dilator Pupilae to dilate eye 
  • Carries sensory info to choroid, iris, and cornea
    • Ophthalmic Nerve 

Travels through ciliary ganglion but does not synapse there!

20

How does parasympathetic innveration work with the eye muscles?

What are its actions?

Preganglioninc Parasympathetic run with Oculomotor nerve and will synapse in ciliary ganglion and then travel with Short Ciliary Nerves 

Actions

  • Innervate Sphincter pupillae
    • Constrict eye 
  • Innervate ciliary muslce
    • Can see farther 
    • Muscle relaxed and flattened  

21

What are the 3 main symptoms of Horner Syndrome?

 

  • Ptosis: droopy eyelid
  • Anhidrosis: No sweat
  • Miosis: constricted pupil

(PAM Horner)

22

A patient who is unable to look laterally with the left eye but is still able to perform all other ocular movements most likely has what disorder? What muscle is affected?

Abducens CN VI

Lateral Rectus M.

23

In a patient with CN IV palsy, what muscle is affected?

How will the patient compensate?

Superior Oblique Muscle

Patient will turn head down and away from the affected side

24

When would a patient complain the most of diplopia if they have trochlear palsy?

When they have downward gaze (reading or walking downstairs)

25

A patient presents with L eye looking down and out, droopy eyelid, and pupil dilation, what cranial nerve has been affected?

Oculomotor Nerve

26

Aneursysm of the follow arteries can affect what autonomic division?

Posterior Cerebral Artery

Posterior Communicating Artery

Superior Cerebellar Artery

Parasympathetic

27

What are the steps of the pupillary light reflex?

  • Step 1: Light synapses at pretectal nucleus
    • Carried by Optic Nerve (sensory)
  • Step 2: Cells from pretectal nucleus will synapse at Edinger-Westphal Nuclues
  • Step 3: Preganglioninc parasympathetic neurons will synapse in ciliary ganglion
    • Carried by Oculomotor Nerve (motor)
  • Step 4: Postganglioninc parasympathetic neurons will synapse in pupillary constrictor muscle 
    • Constriction of Eye

28

How does an afferent lesion affect the pupillary light reflex?

Ipsilateral side will not perform a direct response but will still perform a consensual response because motor innervation is still intact

29

How does an efferent lesion affect the pupillary light reflex?

Ipsilateral side will not have pupillary muscle constriction but the contralateral side will still have a consensual response because afferents are still intact

30

What are the steps of the corneal light reflex?

  • Step 1: Receptors that sesne Touch/Irritation will synapses at trigeminal sensory nucleus.
    • Carried by Ophthalmic Nerve (sensory)
  • Step 2: Cells from trigeminal sensory nucleus will synapse at facial nuclues.
  • Step 3: Facial Nerve will cause blinking (motor)