Lecture 9- The Orbit

Question 1

What is the name for the small reddish body containing modified sebaceous and sweat glands at the medial corner of the eye?

Answer 1

Lacrimal canuncle

Question 2

What is the only eyelid muscle that is not under conscious control?

Answer 2

superior tarsal muscle

Question 3

What is the name for the opening of the lacrimal canal to which tears drain from the eye?

Answer 3

lacrimal puncta

Question 4

What is the name for the swelling/projection on the eyelid near the lacrimal puncta?

Answer 4

Lacrimal papilla

Question 5

What is the white part of the eye called?

Answer 5

sclera

Question 6

What is the opening between the eyelids called?

Answer 6

palpebral fissure

Question 7

What prevents the eyelids from sticking together?

Answer 7

tarsal glands-produce fluid

tarsal plates contain glands

Question 8

Which direction do tears move across the eye?

Answer 8

lateral to medial

Question 9

Name the four structures that tears pass through after they leave the lacrimal gland and travel across the eye?

Answer 9

• drain into superior & inferior lacrimal puncta
• into the superior & inferior lacrimal caniculi
• into the lacrimal sac
• into nasolactrimal duct

lacrimal puncta->lacrimal canicula->lacrimal sac-> nasolacrimal sac

Question 10

What muscle divides the lacrimal gland and thus movement of this muscle “milks” the lacrimal gland?

Answer 10

levator palpebrae superioris

Question 11

Name two ways that tear release is triggered from the lacrimal gland.

Answer 11

parasympathic innervation

milking by the tendon of the levator palpebrae superioris muscle

Question 12

Which nerve moderates tear production?

Answer 12

facial nerve (CN VII)

Question 13

Describe the pathway of the parasympathetic fibers to the lacrimal gland.

Answer 13

presynaptic fibers from greater petrosal nerve (VII)
become nerve to pterygoid canal
synapse in pterygopalatine ganglion
postsynaptic fibers run with branches of V (zygomatic->zygomaticotemporal->lacrimal)

Question 14

Where do parasympathetic of the lacrimal gland synapse?

Answer 14

pterygopalatine ganglion

Question 15

How does paralysis of CN VII affect the eyes?

Answer 15

inability of blinking

Question 16

What nerve controls levator palpebrae superioris?

Answer 16

oculomotor (CN III)

Question 17

What does damage to CN III cause?

Answer 17

ptosis

Question 18

What is the function of the superior tarsal muscle? How is it controlled?

Answer 18

elevates eyelid during sympathetic response

sympathetics

Question 19

Which nerves control the corneal (blink) reflex?

Answer 19

afferent- long & short ciliary (V1)

efferent- VII to orbicularis oculi

Question 20

What is the purpose of the corneal (blink) reflex?

Answer 20

prevent cornea from drying out

contact with foreign objects

Question 21

Name the 7 bones that make up the orbit.

Answer 21

Frontal
Zygomatic
Maxilla
Sphenoid
Ethmoid
Lacrimal
Palatine

Question 22

What is the name of the membrane that surrounds the inner surface of the orbit?

Answer 22

periorbita

Question 23

Name the 7 muscles that move the eye or eyelid.

Answer 23

Levator palpebrae superioris
Superior rectus
Inferior rectus
Lateral rectus
Medial rectus
Superior oblique
Inferior oblique

Question 24

Which muscle abducts the eye?

Answer 24

Lateral rectus

Question 25

Which muscle is innervated by the abducens nerve?

Answer 25

Lateral rectus (CN VI)

Question 26

Which muscle is innervated by the trochlear nerve (CN IV)?

Answer 26

Superior oblique muscle

Question 27

Which muscle opens the eye?

Answer 27

levator palpebrae superioris

Question 28

Which nerve controls opening of the eye?

Answer 28

oculomotor nerve (CN III)- levator palpebrae superioris

Question 29

What is the name for the clinical test used to test individual eye muscles?

Answer 29

H Test

Question 30

What is diploblia?

Answer 30

double vision

Question 31

What muscle is being tested when looking "laterally and upward"?

Answer 31

superior rectus

Question 32

What muscle is being tested when looking "laterally and downward"?

Answer 32

inferior rectus

Question 33

What muscle is being tested when looking "laterally"?

Answer 33

lateral rectus

Question 34

What muscle is being tested when looking "medially"?

Answer 34

medial rectus

Question 35

What muscle is being tested when looking "medially and upward"?

Answer 35

inferior oblique

Question 36

What muscle is being tested when looking "medially and downward"?

Answer 36

superior oblique

Question 37

What are the 4 functions of the eye that are mediated by autonomics?

Answer 37

Accomodation Constriction of pupil Dilation of pupil Involuntary elevation of eyelid

Question 38

What muscle controls accommodation (focusing)?

Answer 38

ciliary muscle

Question 39

What nerves control accommodation?

Answer 39

parasympathetic short ciliary nerves (V1) from ciliary ganglion (fibers originated in oculomotor III)

Question 40

What type of innervation controls constriction of the pupil?

Answer 40

parasympathetic

Question 41

What type of innervation controls dilation of the pupil?

Answer 41

sympathetic

Question 42

Which muscle causes involuntary elevation of the eyelid?

Answer 42

superior tarsal muscle (sysmpathetics)

Question 43

What is the colored part of the eye called?

Answer 43

iris

Question 44

What is the transparent covering over the iris?

Answer 44

cornea

Question 45

What is miosis?

Answer 45

maximum constriction

Question 46

What is mydriasis?

Answer 46

maximum dilation

Question 47

What is Horner's Syndrome?

Answer 47

compression of the sympathetic trunk

Question 48

How does Horner's Syndrome affect the eye?

Answer 48

miosis (constriction)

Question 49

What are four causes of miosis?

Answer 49

light fatigue horner's syndrome morphine

Question 50

What are four causes of mydriasis?

Answer 50

dark excitement, pain oculomotor palsy migraine

Question 51

Where do the sympathetic fibers to the eye synapse?

Answer 51

superior cervical ganglion

Question 52

Where do the parasympathetic fibers in the orbit originate from?

Answer 52

oculomotor (synapse in ciliary ganglion and travel with short ciliary of V1 to eye muscles)

Question 53

What are 3 symptoms of Horner's Syndrome?

Answer 53

ptosis of eyelids Miosis of pupil anhydrosis (lack of sweating)

Question 54

Which muscle of the eye has lost function in Horner's Syndrome?

Answer 54

Superior tarsal muscle

Question 55

Name 5 nerve branches that travel in the cavernous sinus.

Answer 55

``` III IV V1 V2 VI ```

Question 56

What are 5 symptoms of cavernous sinus thrombosis.

Answer 56

- Bulging eyeballs - Cannot move eye in certain direction - Drooping eyelids - Headaches - Vision loss