eyelids & eyebrows

Question 1

function of eyelids

Answer 1

• protect the eye from foreign bodies and excess light
• blinking spreads tears, keeps the cornea moist → essential for good refraction
• blinking moves tears medially (towards middle) for drainage
• eyelids also produce part of the tear film

Question 2

function of eyebrows

Answer 2

• trap sweat, debris, moisture and keep them away from the eyes
• facial expression

Question 3

muscles that produce eyebrow movements

Answer 3

• orbicularis oculi
• occipitofrontalis
• procures

Question 4

what is the orbicularis oculi muscle responsible for, where is it located?

Answer 4

• lowers brow
• around the whole eye
• closing lids
• fibres in circles

Question 5

what is the occipitofrontalis muscle responsible for, where is it located?

Answer 5

• raises brow
• makes you look surprised
• at the top

Question 6

what is the procerus muscle responsible for, where is it located?

Answer 6

• pulls medial brow downwards/ inferiorly
• aggression
• toward inner corner of eye, but the second muscle not first

Question 7

what is the corrugator superciliaris muscle responsible for, where is it located?

Answer 7

• pulls brow medially
• creates vertical glabella lines
• Expression: concentration
• the one closest to inner corner of eye

Question 8

what are muscles that produce eyebrow movements innervated by?

Answer 8

CN VII

Question 9

what are the eyelids?

Answer 9

modified folds of skin that protect of eye from injury

Question 10

gap between upper and lower lid of eyelids

Answer 10

Palpebral fissure

Question 11

where the eyelids meet medially

Answer 11

medial canthus (inner corner of eye)

Question 12

where eyelids meet laterally

Answer 12

lateral canthus (outer corner of eye)

Question 13

features of medial canthus

Answer 13

• lacrimal lake
• plica semilunaris
• caruncle
• lacrimal puncta
• apilla

Question 14

lacrimal lake

Answer 14

collects tears

Question 15

pilica semilunaris

Answer 15

fold of conjunctiva allowing full lateral eye movement without tissue having to stretch

Question 16

caruncle

Answer 16

mound of modified skin

Question 17

lacrimal punch of lid margin

Answer 17

• sits on top of lacrimal papilla
• drainage hole for tears

Question 18

lacrimal papilla of lid margin

Answer 18

• divided lid margin into a ciliary portion and lacrimal portion
• but carrying the the punch

Question 19

ciliary portion of lacrimal papilla

Answer 19

lashes and glands

Question 20

lacrimal portion of lacrimal papilla

Answer 20

no lashes

Question 21

Sagittal Section of the Eyelid (Superficial → Deep)

Answer 21

1. Skin
2. Subcutaneous tissue
3. Orbicularis oculi muscle
4. Tarsal plate
5. Superior tarsal muscle (Müller’s)
6. Palpebral conjunctiva

Question 22

Orbicularis oculi muscle

Answer 22

• sphincter muscle that closes eyelids
• innervated by facial nerve

Question 23

4 muscles of the eyelids

Answer 23

1. Orbicularis oculi
2. Levator palpebrae superioris (LPS)
3. Superior tarsal muscle (Müller’s muscle)
4. Inferior tarsal muscle

Question 24

Levator palpebrae superioris (LPS)

Answer 24

• elevates upper eyelid
• origin: lesser wing of sphenoid
• inserts into superior tarsal plate
• has a broad, flat aponeurosis with:
• lateral horn – supports lacrimal gland
• innervation: Oculomotor nerve (CN III)
• damage → ptosis

Question 25

Superior tarsal muscle (Müller's muscle)

Answer 25

- smooth muscle - additional 2 mm elevation - sympathetic innervation - originates from LPS (Levator palpebrae superioris)

Question 26

glands of eye

Answer 26

1. Glands of Moll 2. Glands of Zeis 3. Tarsal glands / Meibomian glands

Question 27

Inferior tarsal muscle

Answer 27

- small - depresses (moves it down) lower lid slightly - sympathetic innervation

Question 28

Glands of Moll

Answer 28

- modified sweat glands near lash base - protect lash & ocular surface - empty into hair follicle

Question 29

Glands of Zeis

Answer 29

- sebaceous glands - secrete sebum - lubricate eyelashes - blockages → styes

Question 30

tarsal / meibomian glands

Answer 30

- located in tarsal plates (30–40 per lid) - oily secretion forms part of tear film - prevents tear evaporation

Question 31

Tarsal Plates

Answer 31

- strengthened bands of connective tissue - provides structure and shape - dense connective tissue plates - superior plate larger than inferior - contain Meibomian glands - held by medial and lateral palpebral ligaments - medial is stronger

Question 32

what does the medial palpebral ligament attach to?

Answer 32

lacrimal crest

Question 33

what does the lateral palpebral ligament attach onto?

Answer 33

zygomatic bone

Question 34

orbital septum

Answer 34

- dense connective tissue sheet - acts as barrier to infection - extends across orbit and inserts into tarsal plates

Question 35

neurovascular (blood) supply of eyelids

Answer 35

- arterial arcades from: - Medial palpebral artery - Lateral palpebral artery (both from ophthalmic artery) - veins similarly named → drain into ophthalmic vein

Question 36

nerve supply to upper eyelid

Answer 36

supraorbital nerve (branch of CN V1)

Question 37

nerve supply to lower eyelid

Answer 37

infraorbital nerve (branch of CN V2)

Question 38

Lymphatic Drainage

Answer 38

- Medial half drains into submandibular nodes - Lateral half drains into parotid (superficial + deep) nodes