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Ophthalmology > Anatomy > Flashcards

Flashcards in Anatomy Deck (81)
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1
Q

What bones are involved in the orbit of the eye?

A
Orbital plate of frontal bone
Orbital plate of ethmoid bone
Lacrimal 
Maxilla
Zygoma
Sphenoid
2
Q

What protects the eye from trauma?

A

orbital margins / orbital rim

3
Q

What parts of the orbit are thinnest and affected by orbital blowout fractures?

A

Medial wall and orbital floor

4
Q

What are the two parts of the orbicularis oculi muscle?

A

Orbital part

Palpebral part

5
Q

What is the function of levator palpebrae superioris?

A

retracting the upper eyelid

6
Q

What does the conjunctiva cover in the eye?

A

Lower eyelid and upper eyelid

Also covers sclera and cornea

7
Q

What part of the eye does the cornea cover?

A

iris and pupil

8
Q

What is the function of the conjunctiva?

A

defensive barrier to foreign bodies penetrating deep to it into the orbit

9
Q

What apparatus is used in the production of tears?

A

Lacrimal Apparatus

10
Q

Explain how tears are produced and collected in the eye

A

Lacrimal gland produces lacrimal fluid (tears)

Pushed over eye towards medial angle by eyelashes

Drains through lacrimal puncta

11
Q

What are the 2 parts which make up the fibrous outer layer of the eye?

A

sclera

cornea

12
Q

What is the name of the vascular layer in the eye?

A

UVEA

13
Q

What are the 3 components of the uvea (vascular layer in the eye)?

A

3 part:

  • iris
  • ciliary body
  • choroid
14
Q

What is the main function of the choroid in the vascular layer?

A

nutrition and gas exchange

15
Q

What type of fluid is found in the anterior segment?

A

Aqueous humour

16
Q

What type of fluid is found in the posterior segment?

A

Vitreous Humour

17
Q

Where are the anterior or posterior segments found?

A

Anterior segment = in front of lens

Posterior segment = behind lens

18
Q

What is the main artery which supplies the eye?

A

Ophthalmic artery

19
Q

The ophthalmic artery branches from the external carotid. TRUE/FALSE?

A

FALSE

Internal Carotid

20
Q

What artery supplies the retina and where can it be found?

A

The central artery of the retina (end artery found within optic nerve)

21
Q

What is the danger triangle?

A

Area of the face where infection can potentially track back up venous system to the eye

22
Q

What is the area of most acute vision called and where is it located in the eye?

A

Fovea

found in the centre of the macula

23
Q

Why is the optic disc thought of as the blind spot?

A

There are no photoreceptors in the disc

24
Q

How many extraocular muscles do we have and what type of muscle fibre are they made up of?

A

7 skeletal muscles

4x Rectus, 2x Obliques, Levator Palpebrae Superioris

25
Q

Name the 4 rectus extraocular muscles?

A

superior rectus
inferior rectus
medial rectus
lateral rectus

26
Q

Where do the rectus muscles originate and insert?

A

origin = common tendinous ring

insertion = sclera

27
Q

What are the two oblique extraocular muscles?

A

superior oblique

inferior oblique

28
Q

What cranial nerve supplies the lateral rectus muscle?

A

Lateral Rectus ABDUCTS eye

=> CN VI ABDUCENS

29
Q

What cranial nerve supplies the superior oblique muscle?

A

Superior oblique passes through TROCHLEAR pullley before inserting onto sclera
=> CN IV TROCHLEAR

30
Q

What cranial nerve supplies the rest of the extraocular muscles?

A

CN III

Oculomotor

31
Q

What parts of the face have sensory innervation from CN V1?

A

upper eyelid
cornea
conjunctiva
skin of middle of nose

32
Q

Where does the maxillary division of the trigeminal nerve give sensory innervation?

A

skin of the lower eyelid
skin over the maxilla
skin over nostrils
skin/mucosa of the upper lip

33
Q

The skin over the mandible and temporomandibular joint are innervated by what cranial nerve?

A

CN V3

Mandibular division of the trigeminal nerve

34
Q

What are the 3 main parts of every reflex?

A

Sensory
Central CNS Connections
Motor

35
Q

Explain the pathway of the Blink (Corneal) Reflex?

A

Sensory:

  • from cornea via CN V1 branches
  • To trigeminal ganglion
  • Along CN V to pons

Central CNS connections between CN V and CN VII (facial nerve)

Motor:

  • CN VII
  • To eyelid part of orbicularis oculi
  • Makes eyelid close (=> Blink)
36
Q

Where do pre-synaptic sympathetic fibres exit the spinal cord to travel to the eye?

A

T1 level

then travel up sympathetic chain

37
Q

Where do sympathetic signals synapse on their course to the eye?

A

Superior cervical ganglion

38
Q

What arteries are responsible for transporting post-synaptic sympathetic fibres to the eye?

A

Surface of the internal & external carotid arteries

Ophthalmic artery carries sympathetic axons into the orbit

39
Q

What cranial nerves are involved in parasympathetic outflow?

A

CN III Oculomotor
CN VII Facial
CN IX Hypoglossal
CN X Vagus

40
Q

What are the two ganglions in which parasympathetic signals synapse on route to the eye ?

A

Ciliary Ganglion

Pterygopalatine Ganglion

41
Q

What extraocular muscles are innervated by CN III?

A

Superior, Medial and Inferior Rectus
inferior oblique
Levator palpebrae superioris

42
Q

CN III supplies the extraocular muscles in a superior and inferior division. Which division supplies which muscle?

A

Superior division:
Superior Rectus and Levator Palpebrae Superioris

Inferior division:
Medial Rectus, Inferior Rectus, Inferior Oblique

43
Q

Long ciliary nerve contains both sympathetic and parasympathetic parts. TRUE/FALSE?

A

FALSE
Only has sympathetic and somatic sensory
Short ciliary nerve contains both

44
Q

What do sympathetic signals cause the eye to do?

A

open eyes wider
get more light into eyes
focus on far objects
emotion

45
Q

What are the parasympathetic effects on the eye?

A

allow orbicularis oculi to work (closes eye)
get less light into eyes (protect retina from bright light or when asleep)
focus on near objects
reflex lacrimation

46
Q

Leavtor palpebrae superioris is made up of skeletal muscle. TRUE/FALSE?

A

FALSE

Contains both skeletal and smooth muscle

47
Q

What is the name given to drugs which will dilate the pupil?

A

mydriatic drugs

48
Q

Where do the dilator pupillae fibres originate and insert in order to dilate the pupil?

A
origin = external circumference of iris – fixed
insertion = internal circumference of iris - mobile
49
Q

What muscle is in charge of constricting the pupil?

A

sphincter pupillae fibres encircle pupil

50
Q

What does a pin point pupil indicate?

A

Opiate drug use

51
Q

What does a fixed dilated pupil indicate?

A

CN III pathology

52
Q

Describe the pupillary lihttps://www.brainscape.com/packsght reflex?

A

Sensory
ipsilateral CN II

CNS connections in midbrain

motor
bilateral response via CNs III
(therefore both eyes respond to light being shone in one eye)

53
Q

The pupillary light reflex is named differently depending on which eye the light is shone into. Describe the two types of this reflex?

A

direct light reflex occurs in the stimulated eye

consensual light reflex occurs in the non-stimulated eye

54
Q

What structures are responsible for controlling the lens?

A

ciliary body

suspensory ligament of lens

55
Q

How is the shape of the lens controlled by the ciliary body to use “far vision”?

A

Ciliary muscle relaxes in far vision
=> Ligament tightens and flattens lens
NO parasympathetics involved

56
Q

What shape is the lens when “near vision” is being used?

A

Spherical as ligaments are relaxed due to muscle contraction

This is controlled by parasympathetics

57
Q

What are the 3 parts of the accommodation reflex?

A

Reflex = Bringing objects from far to near

bilateral pupil constriction (CN III)
bilateral convergence - medial rotation of both eyes
bilateral relaxation of the lens

58
Q

What are the 3 types of tears which can be produced?

A

basal tears (clean/nourish and hydrate)

reflex tears (response to mechanical or chemical stimulation)

emotional tears
happy, sad or frightened tears

59
Q

What can cause raised intracranial pressure?

A
Head injury
space occupying lesion/tumour/abscess 
haemorrhage
hydrocephalus
meningitis
60
Q

What are the 3 layers of meninges?

A

Dura Mater
Arachnoid Mater
Pia Mater

61
Q

How does hydrocephalus appear clinically?

A

Head almost transparent
vessels visible
Sunset sign (white of eyes visible above iris)

62
Q

The endosteal and meningeal layers make up what structure in the brain?

A

The dura mater

63
Q

What lies between the arachnoid and pia mater and what is found here?

A

Sub arachnoid space

CSF found here

64
Q

The pia mater is in close contact with the brain. TRUE/FALSE?

A

TRUE

single cell layer that lies in sulci => direct contact

65
Q

Veins which arise between the two layers of dura mater are knwon as what?

A

Dural venous sinuses

not veins as they have no vessel wall, they are contained by the two layers of dura mater

66
Q

The meninges form a double layer at the longitudinal fissure between the two cerebral hemispheres. What is this called?

A

Falx Cerebrae

67
Q

What is the horizontal layer of meninges in the brain called?

A

Tentorium Cerebelli

68
Q

The brainstem passes through the tentorium notch. TRUE/FALSE?

A

TRUE

69
Q

How does CSF flow between the lateral and third ventricles?

A

Intra-ventricular foramen

70
Q

What connects the third and fourth ventricles?

A

Cerebral aquaduct

71
Q

After leaving the fourth ventricle, what are the possible pathways for the CSF?

A

Either:
Central canal of the spinal cord
OR through the lateral/median apertures

(After the apertures CSF flows to:

  • subarachnoid space
  • arachnoid villi
  • superior sagittal sinus
  • drains into venous system
72
Q

What eye symptoms usually present with raised Intracranial pressure?

A
transient blurred vision
double vision (diplopia)
loss of vision
papilloedema (swelling of optic disc)
pupillary changes
73
Q

What veins are at risk if a patient suffers a head injury?

A

cerebral veins

74
Q

Why are the optic nerves thought to be a extension of the brain rather than a true cranial nerve?

A

They are covered by the 3 layers of meninges

75
Q

Where does the subarachnoid space extend to in the eye?

A

The back of the eyeball

76
Q

A swollen optic disc can compromise what other structures?

A

Compress central artery and vein of the retina

77
Q

If raised intracranial pressure is present behind the eye, what symptoms can patients experience?

A

transient visual obscurations/ flickering
blurring of vision
constriction of the visual field
decreased colour perception

78
Q

Where does the eye move to if there is a CN III palsy?

A

Down and out

Due to Superior Oblique and Lacteral Rectus still working

79
Q

Where does the eye move to if there is a problem with the trochlear nerve?

A

Moves up when asked to look medially
Due to non-functioning superior oblique
=> inferior oblique is unopposed

80
Q

Loss of function in the abducens nerve causes the eye to sit where?

A

Medially

as lacteral rectus cant abduct the eye

81
Q

How is papilloedema graded?

A
Grade 1 - C shaped Halo and blurred vision
Grade 2 - closed halo
Grade 3 - Peripheral vessels disappear
Grade 4 - Central vessels disappear
Grade 5 - All vessels disappear