The eye and sight

Question 1

bones contributing to the orbit framework

Answer 1

Superior wall: Frontal bone; lesser wing of sphenoid bone
Medial wall: Maxilla; Lacrimal; Ethmoid; lesser wing of sphenoid bone
Inferior wall: Maxilla; Zygomatic and Palatine bones
Lateral wall: Zygomatic (anteriorly); Greater wing of sphenoid (posteriorly)

Question 2

2 groups of muscles within the orbit

Answer 2

Extrinsic / extra-ocular muscles - move eyeballs or raise upper eyelids

Intrinsic muscles - within eyeball - control shape of lens and size of pupil

Question 3

The muscle above the superior rectus

Answer 3

Levator Palpaberae Superioris

Question 4

Orbicularis Oculi

Answer 4

Not extrinsic muscle of eye
has two parts:
Orbital part - surrounds orbit, involved when eye tightly closed
Palpebral part - the eyelid, involve when eye gently closed

Question 5

Muscles supplied by oculomotor nerve (3)

Answer 5

Superior rectus, Inferior rectus, Medial rectus, Inferior Oblique
LPS (levator palpebrae superioris)

Question 6

Muscles supplied by abducens nerve (6)

Answer 6

Lateral rectus

Question 7

Muscles supplied by trochlear nerve (4)

Answer 7

Superior Oblique

Question 8

Eye movement caused by the: Lateral rectus

Answer 8

abduction

Question 9

Eye movement caused by the: Medial rectus

Answer 9

Adduction

Question 10

Eye movement caused by the: Superior rectus

Answer 10

Up and in (adduction)

Question 11

Eye movement caused by the: Inferior rectus

Answer 11

Down and in (adduction)

Question 12

Eye movement caused by the: Superior Oblique

Answer 12

Down and out (abduction)

Question 13

Eye movement caused by the: Inferior Oblique

Answer 13

Up and out (abduction)

Question 14

Clinical testing for: Lateral rectus

Answer 14

Ask to abduct eye

Question 15

Clinical testing for: Medial rectus

Answer 15

Ask to adduct eye

Question 16

Clinical testing for: Superior rectus

Answer 16

Ask to first abduct eye (out), then look down

Question 17

Clinical testing for: Inferior rectus

Answer 17

Ask to first abduct eye (out), then look up

Question 18

Clinical testing for: Superior oblique

Answer 18

Ask to first adduct eye (in), then look down

Question 19

Clinical testing for: Inferior oblique

Answer 19

Ask to first adduct eye (in), then look up

Question 20

Innervation of Levator Palpebrae Superioris

Answer 20

Oculomotor and sympathetic innervation

Question 21

Sympathetic loss to LPS and oculomotor loss

Answer 21

Sympathetic loss - ptosis

Oculomotor loss - closed eyelid

Question 22

Arterial supply to the orbit and eyeball

Answer 22

Ophthalmic artery - branch of the internal carotid artery immediately after it leaves the cavernous sinus

Question 23

Ophthalmic artery passes into the orbit via the…with….

Answer 23

via the optic canal with the optic nerve

Question 24

Name the nerves and vessels passing through the optic canal

Answer 24

Optic nerve

Ophthalmic artery

Question 25

Name the nerves and vessels passing through the superior orbital fissure

Answer 25

``` Oculomotor nerve (3) Trochlear nerve (4) Ophthalmic division of the trigeminal nerve (V1) Abducens nerve (6) Ophthalmic veins Sympathetic fibres ```

Question 26

Name the nerves and vessels passing through the inferior orbital fissure

Answer 26

Maxillary division of the trigeminal nerve (V2) Inferior ophthalmic vein Infraorbital vessels

Question 27

Explain the clinical significance of the close relationship between the superior orbital fissure and the cavernous sinus

Answer 27

The superior ophthalmic veins drain into the cavernous sinus through the superior orbital fissure Provides a potential route for infection from the orbit and nasal sinuses This can lead to a cavernous sinus thrombosis

Question 28

Describe the corneal/ pupillary reflex

Answer 28

1) Photoreceptors detect light. Optic nerve --> pretectal nucleus 2) --> the Edinger-Westphal nucleus 3) Motor signal --> oculomotor nerves --> ciliary ganglia 4) --> Parasympathetic innervation of the pupillary sphincter --> constriction of the pupil

Question 29

Testing reflex: shine light in 1 eye. Constriction in tested eye means: Contraction in other eye means:

Answer 29

Tested eye: Good optic nerve function | Other eye : Good oculomotor nerve function

Question 30

Branches of V1 (ophthalmic nerve of trigeminal)

Answer 30

Fine Looking Nipples Frontal Nerve Lacrimal Nerve Nasociliary Nerve

Question 31

What stimulation by what fibres causes fluid secretion from the lacrimal gland?

Answer 31

Parasympathetic stimulation by secretomotor fibres

Question 32

Ducts from the lacrimal gland open into the | which empties over the

Answer 32

Conjunctival sac which empties over the eyeball

Question 33

Tear drainage

Answer 33

Tears pass medially over the surface - -> puncta and lacrimal canaliculi - -> collect in the lacrimal sac - -> lacrimal duct - -> Internal meatus of nasal cavity