Ocular Anatomy 3 Eyelids

Question 1

Describe the orbital septum

Answer 1

Continuous witht he periosteum and the orbital margins
Centrally forms the palpbral fissure
Above and below the palpebral fissure suptum is thickened forming upper and lower tarsal plates

Question 2

What do the upper and lower tarsal plates measure centrally

Answer 2

Upper 10mm
Lower 5mm

Question 3

Where do the upper and lowertarsal plates connect and with what?

Answer 3

Connected to anterior lacrimal crest by the medial palpebral ligament
tO the marginal tubercle by the lateral palpebral ligament

Question 4

What is the lateral palpebral raphe

Answer 4

Interlacing fibres of the palpebral part of orbicularis oculi and lies anterior the the lateral palpebral ligament

Question 5

What are the layers of the eyelids from superficial to deep

Answer 5

Skin
Subcutaneous tissue
Striated muscle fibres of ocrbiularis oculi
Neurovascular bundle
Orbital septum tarsal plates
Conjunctiva

Question 6

Where are the Meibomian glands located? How many are there?

Answer 6

Embedded in thin tarsal plates
35 in upper lid, 25 in lower lid

Question 7

Where do the glands of the eyelid open?

Answer 7

Meibomian open behind the lash follicles
Glands of Zeis open into each follicle
Glnds of Moll open between follicles

Question 8

What are the types of gland?

Answer 8

MEibomian - sebaceous
Zeiss - sebaceous
Moll -modified sweat galnds

Question 9

Where does the conj become continuous with skin epithelium?

Answer 9

Along the posterior margins of the tarsal gland openings (posterior to grey line)

Question 10

What is the grey line?

Answer 10

Tissue plane along which the eyelid may be split into an anterior lamella (skin, subcut tissue and orbicularis), and posterior lamella (tarsal plate and conjunctiva)

Question 11

Describe the origin, path and insertion of the levator palpebrae superioris

Answer 11

Originates above the tendinous ring and passes forward above the superior rectus before fanning out into a broad aponeurosis.
Aponeurosis descends into the upper lid behind the orbital septum, which it pierces before attaching to the superior tarsal plate.
Some fibres pass forward between the the fibres or orbicularis oculi to from the primary lid crease

Question 12

What innervates the levator palpebrae superioris

Answer 12

Superior branche of the oculomotor nerve

Question 13

How high can the levator lift the upper lid?

Answer 13

15mm

Question 14

How else does the eyelid lift?

Answer 14

Mullers muscle - arises from the inferior aspect of the aponeurosis
Smooth muscle that inserts into the upper edge of the superior tarsal plate
Innfervated by sympathetic fibres
15-20mm wide

Question 15

Where is the orbicularis oculi derived from?

Answer 15

2nd branchial arch

Question 16

What innervates the orbicularis oculi?

Answer 16

Facial nerve - temporal and zygomatic branches

Question 17

Where does the orbicularis oculi lie?

Answer 17

Palpebral part of the muscle lies on eather side of the palpebral fissure extending from medial palpebral ligament to the lateral palpebral raphe.
Infront of the orbital septum

Question 18

What are the functions of the orbicularis oculi?

Answer 18

Palpebral potion - relfex blinking
Orbital postion - binding eyelids tightly together
Pumping action of tears from conjnctiva to the lacrimal sac

Question 19

What is the arterial supply to the eye lids?

Answer 19

Lateral palpebral arteries (from lacrimal artery)
Medial palpebral arteries (from ophthalmic artery)

Question 20

What is the venous drainage of the eyelids?

Answer 20

MEdially:
Ophthalmic and angular veins

LAteral:
Superficial temporal vein

Question 21

What is the lymphatic drainage of the eyelids?

Answer 21

Lateral two thirds of upper and lower lids:
Superficial parotid nodes

Medial:
Submandibular nodes

Question 22

What is the innervation of the eyelids?

Answer 22

Upper lid:
Lacrimal nerve V1
Supraorbital nerve
Supratrochlear nerve

Lower lid
Infraorbital division of maxillary nerve V2
Infratrochlear nerve (from ophthalmic nerve V1)