Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Anatomy - Head, neck and spine > Eye and orbit > Flashcards

Eye and orbit Flashcards

1
Q

Which bone forms the roof of the orbit?

A

orbital plate of the frontal bone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Which bone forms the floor of the orbit?

A

orbital plate of the maxilla

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Which bones form the lateral wall of the orbit?

A

zygoma and greater wing of sphenoid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Which bones form the medial wall of the orbit?

A
  • front process of maxilla
  • lacrimal bone
  • orbital plate of ethmoid
  • lesser wing of sphenoid
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the 3 orbital foramina?

A
  • optic canal
  • inferior orbital fissure
  • superior orbital fissure
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What exits through the optic canal?

A

Optic nerve (II) and ophthalmic artery

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What exits through the inferior orbital fissure?

A

Maxillary division of the trigeminal nerve (V2) and the infraorbital vessels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What exits through the superior orbital fissure?

A
  • Ophthalmic division of the trigeminal nerve
  • Oculomotor nerve
  • Trochlear nerve
  • Abducens nerve (VI)
  • Ophthalmic vessels and Sympathetic fibres
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How many extrinsic eye muscles are there and how are they divided?

A

6:
4 recti
2 obliques

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the 4 recti muscles?

A

Inferior, superior, medial and lateral

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Where do the recti muscle originate and insert?

A
  • Originate at the back of the obit, in the common tendinous ring
  • Insert into the sclera, 5mm behind the corneal margin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the nerve supply to the recti muscles?

A
  • Inferior, superior and medial recti supplied by oculomotor
  • Lateral rectus supplied by abducens
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the two oblique muscles?

A

inferior and superior

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Where does the superior oblique originate, insert and what is its nerve supply?

A
  • Originates in the body of the sphenoid
  • Insert the globe in the posterior/superior quadrant, via the trochlear
  • Nerve supply: trochlear
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Where does the inferior oblique originate, insert and what is its nerve supply?

A
  • Originates in the orbital surface of maxilla
  • Insert the globe in the posterior/inferior quadrant
  • Nerve supply: oculomotor
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are some symptoms of Horner’s syndrome?

A

Ptosis (drooping upper eyelid), myosis (constriction) , aanhidrosis (inability to sweat)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the levator palpebrae superiosis?

A

muscle of the upper eyelid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Where does the levator palpebrae superiosis originate, insert and what is its nerve supply?

A
  • Originates in the lesser wing of the sphenoid
  • Inserts at the superior tarsal plate and skin of the eyelid
  • Nerve supply: oculomotor (III) and sympathetic innervation to smooth muscle
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

If the muscles of the eye were working in isolation what would each of them do?

A

Lateral rectus: purely abduction action

Medial rectus: adducts towards midline

Superior oblique: depressor and abductor

Inferior oblique: elevator and abductor

Superior rectus: elevator and adductor

Inferior rectus: depressor and adductor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How can the eye muscles be tested (LR, MR)?

A

The lateral rectus: abducts in right eye, adducts in left

The medial rectus: adducts in left eye, adducts in right

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

How can IR and SO be tested for?

A

IR, SO are involved in depressing the eye. Therefore, asking a patient to look down will not test the function of any one muscle in isolation. To test function, you adduct or abduct the eye, before asking the patient to look down.

  • When the eye adducts towards the midline, the only muscle contributing to depression then is the SO
  • When the eye abducts away from the midline, the only muscle contributing to depression is the IR
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What makes up the optic nerve?

A

The axons from the ganglion cells in the retina

23
Q

What does the oculomotor nerve do?

A

Motor fibres to MR, SR, IR, IO & LPS and parasympathetic fibres

24
Q

What does the trochlear nerve do?

A

Motor fibres to SO

25
Q

What does the abducens nerve do?

A

Motor fibres to LR

26
Q

What are the nerves of the orbit?

A
  • optic
  • oculomotor
  • trochlear
  • opthalmic
  • abducens
27
Q

Describe the pathway of the opthalmic nerve

A

It travels laterally to the cavernous sinus and gives rise to the recurrent tentorial branch (which supplies the tentorium cerebelli).
It then exits the cranium via the superior orbital fissure, where it divides into its 3 branches.

28
Q

What are the three branches of the opthalmic division of the trigeminal?
What do they do

A
  • Frontal nerve, lacrimal nerve and nasociliary nerve

- Provide sensory innervation to the skin and mucous membranes of the structures derived from the frontonasal prominenc

29
Q

Which nerves pass through the carvernous sinus (sits either side of the sphenoid)?

A
  • trochlear
  • oculomotor
  • abducens
  • maxillary division of trigeminal
  • opthalmic division of trigeminal
30
Q

Which artery passes through the sinus?

A

internal carotid

31
Q

What is the clinical significance of these nerves being in the sinus?

A

If you get an infection in the carotid sinus, it can directly affect all of the cranial nerves listed

32
Q

What does the lacrimal nerve do?

A

Goes out to the lacrimal gland area

33
Q

What does the frontal nerve (branch of opthalmic) divide into and what do they do?

A
  • Divides into the supratrochlear and supraorbital nerves

- Sensory innervation of skin

34
Q

What does the nasociliary branch of the opthalmic divide into?

A

branch to ciliary ganglion, ethmoidal branch, infratrochlear branch

35
Q

Where is the ciliary ganglion?

A

behind the eye

36
Q

What is the ciliary ganglion?

A
  • Has parasympathetic fibres
  • Preganglionic fibres are in the inferior ramus of the oculomotor nerve
  • he postganglionic fibres are in the short ciliary nerves
  • They supply the sphincter pupillae muscle and ciliary muscles of the eye
37
Q

What does the opthalmic artery supply blood to?

A
  • Central artery of the retina
  • Muscular branches
  • Ciliary branch
  • Lacrimal branch
  • Supratrochlear branch
  • Supraorbital branch
38
Q

What are the opthalmic veins called and where do they drain?

A
  • Superior ophthalmic vein drains back into the cavernous sinus
  • Inferior ophthalmic vein drains back into the pterygoid plexus
39
Q

What is the clinical significance of the drainage pathways of the opthalmic veins?

A
  • Superior drains back into the cavernous sinus – potential route of infection
  • Inferior into the pterygoid plexus – no passage into cranial cavity
40
Q

Where is the lacrimal gland located and where does it get innervation from?

A
  • In the anterolateral superior orbit
  • Tucked in just beneath the LPS
  • Parasympathetic secretomotor fibres come from the facial nerve from the pterygopalatine ganglion via zygomaticotemporal and finally lacrimal nerves
41
Q

Describe the branching and joining of nerve to form the lacrimal nerve going to the gland

A
  • Parasympathetic stimulation by secretomotor fibres stimulate fluid secretion from the lacrimal gland
  • The pterygo-palatine ganglion contains parasympathetic post-ganglionic secretomotor fibres, sending branches out from the maxillary division of the trigeminal nerve
  • These join with parasympathetic secretomotor fibres from the facial nerve to form the lacrimal nerve (via zygomaticotemporal nerves)
  • The lacrimal nerve passes to the lacrimal gland
42
Q

Where is the lacrimal sac?

How does it drain?

A
  • medial canthus of the eye

- drains into the nose via the nasolacrimal duct into the inferior meatus of the nose

43
Q

What does the lacrimal gland do?

A

secretes tears, which wash across the cornea

44
Q

What is the function of tears and the drainage pathway?

A
  • Protective function, and keep the eye lubricated
  • Tears go throught the lacrimal canaliculi into the lacrimal sac, and drain through the nasolacrimal duct, into the nose
45
Q

What can happen if you lose lacrimation and what may this be a sign of?

A

Eyes become dry and this is painful

May be a parasympathetic issue

46
Q

Describe the autonomic pathway in the eye (PNS)

A

Optic nerve and tract -> pretectum -> Edinger-Westphal nucleus (parasympathetic) -> oculomotor nerve -> ciliary ganglion -> sphincter pupillae and ciliary muscles for miosis and lens thickening

47
Q

Describe the autonomic pathway in the eye (SNS)

A

T1 -> superior cervical ganglion -> carotid plexus -> branches of ophthalmic artery -> dilator pupillae, tarsal muscle (part of levator palpebrae superioris) and blood vessels

48
Q

Orbicularis Occuli

A
  • Surrounds eye
  • Innervation: Facial nerve VII
  • Lesion to VII: Inability to shut eyes tightly - tear
    spillage and dry eye
49
Q

How to test CN 3?

A

Motor functions: Move the eyeball

Parasympathetic functions - light reflex, accommodation reflex

50
Q

What happens if CN 3 is damaged?

A

Loss of movement of ocular muscles except LR and SO
- Eye in ‘down and out’ position

Loss of innervation to the levator palpabrae superioris
- Complete ptosis

Loss of parasympathetic function:
Dilated pupil (mydriasis)
51
Q

How to test for orbicularis oculi

A
  • Screw eyes shut
52
Q

What happens if there is impaired sympathetic innervation?

A

Horner’s syndrome – lesion to the upper sympathetic trunk
Usually caused by an apex lung tumour (Pancoast’s tumour)

  • Partial ptosis as only the superior tarsal muscle is affected, not the levator palpebrae superioris)
  • Miosis (constricted pupil)
  • Anhydrosis (reduced sweating)
  • Lesion to the entire oculomotor -> complete ptosis
53
Q

Relevant Afferent Pupillary defect

A
  • When the pretectal nucleus receives an afferent input, it communicates with both Edinger-Westphal nuclei such that there is an efferent response in the
    ipsilateral (direct response) and contralateral (consensual response) eyes.
  • If there is damage in the afferent pathway, then the following phenomenon is seen (relevant afferent pupillary defect).
  • When light is shined on the undamaged eye, both pupils constrict, as there is a direct and consensual response.
  • When light is immediately switched to the damaged eye, then, as there is no afferent response, there is no efferent response, and so the eyes stop constricting and instead they dilate back to neutral.
54
Q

Corneal Reflex

A

Afferent: Sensation to touch is conducted via the ophthalmic Nerve (V1)

Efferent: Facial motor nucleus (VII) 🡪 along facial nerve to orbicularis oculi (snaps the eye shut)

Anatomy - Head, neck and spine (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions