ORBIT & OCULAR ADNEXAE - Eyelids

Question 1

What is the grey line of the eyelid? What does it divide?

Answer 1

Gray line divides the eyelid margin into the anterior lamina and posterior lamina

Anterior to tarsal plate
Posterior to lash line.

Question 2

What is the difference between the gland of zeiss and the gland of moll in terms of
1. Location
2. Lobularity
3. Function

Answer 2

1. Zeiss : at the margin of the eyelid,
   Moll: between cilia (eyelash) and anterior lid margin
2. Zeiss: unilobular
   Moll: unbranched spiral shape
3. Zeiss: modified sebaceous gland that produces sebum to prevent eyelashes from becoming dry and brittle
   Moll: apocrine sweat gland

Question 3

What is the horizontal and vertical measurement of the palpebral fissure?

Answer 3

horizontal - 30mm
vertical - 10mm

Question 4

What is a mongoloid slant? Which strabismus pattern does it exhibit

Answer 4

Elevation of lateral canthus > 2mm
Pseudo A pattern strabismus

Question 5

What conditions have mongoloid slant?

Answer 5

Down’s syndrome
Noonan’s syndrome

Question 6

What conditions have Anti-mongoloid slant? What strabismus pattern?

Answer 6

Treacher collin syndrome
Coffin lowry syndrome
Zygomatic maxillary complex fracture
Pseudo V pattern strabismus

Question 7

What are the 9 layers of the eyelid from outside to inside?

Answer 7

1. Skin - v thin loosely adhered to muscle
2. Subcutaneous areolar tissue - only fat
3. Striated muscle layer (orbicularis)
4. Submuscular areolar tissue
5. Fibrous layer (tarsal plate and orbital septum)
6. Orbital Fat
7. Levator Aponeurosis
8. Non-striated muscle layer - Muller’s muscle
9. Conjunctiva

Question 8

What are the two parts of the orbicularis muscle? What is their function?

Answer 8

1. Orbital part - forced closure of eyelid
2. Palpebral part - gentle closure of eyelid

Question 9

Which layer consists of the nerves and vessels of the eyelid? What does this layer connect with?

Answer 9

Submuscular areolar tissue

Communicates with striatum of scalp - dangerous area of scalp and can act as communication for pus/blood between two areas

Question 9

What is the tarsal plate?

Answer 9

Dense fibrous tissue of the eyelid giving strength and firmness, has meibomian glands embedded within it

Question 10

What is the upper and lower tarsal height?

Answer 10

Upper : 10mm
Lower: 5mm

Question 11

How many meibomian glands are there?

Answer 11

20-30 on each lid

Question 12

What do meibomian glands produce?

Answer 12

Sebaceous glands (like Zeiss glands) Produce lipids (meibum) that forms the outer layer of tear film to stop evaporation

Question 13

What is attached to the superior tarsal border? (2)
What structure is attached below the superior tarsal border?

Answer 13

1.Orbital septum and muller’s muscle
2. LPS aponeurosis attaches 3-4mm below,

Question 14

What is attached to the inferior tarsal border? (3)

Answer 14

Orbital septum
capsulopalpebral fascia
inferior palpebral/tarsal muscle (lockwood ligament) which connects to the inferior rectus

Question 15

What are the lateral ends of the tarsus attached to?
What are the medial ends of the tarsus attached to?

Answer 15

Lateral: whitnal tubercle by lateral palpebral ligament
Medial: attach to anterior lacrimal crest and frontal process of maxillla by medial palpebral ligament

Question 16

What is the muller’s muscle and inferior palpebral muscle innervated by?

Answer 16

sympathetic nerve fibres – irritation leads to retraction of lids –> paralysis leads to horner’s syndrome

Question 17

What is the difference between cyst of zeiss and cyst of moll?

Answer 17

Zeiss: non-translucent, obstructed sebaceous gland with eyelash follicle (picture)

Moll: Translucent - retention cyst of apocrine sweat gland

Question 18

Which nerve supplies the upper lid (4)
Which nerve supplies the lower lid (2)

Answer 18

Upper: Infratrochlear, Supratrochlear, Supraorbital, Lacrimal

Lower: Infraratroclear, Infraorbital.

Question 19

What is the origin and insertion of Muller’s muscle?

Answer 19

Origin: Underside of LPS
Route: Travels inferiorly between levator aponeurosis and conjunctiva
Insertion: Inserts into superior border of tarsus

Question 20

Where is the origin and insertion of the LPS? What happens to its medial horn?

Answer 20

Origin: Lesser wing of sphenoid bone above the optic canal

Insertion: Superior tarsal plate.

Medial horn of aponeurosis inserts into frontolacrimal suture.

Question 21

When do the eyelids form embryologically?

Answer 21

4-5 weeks upper eyelid forms first from surface ectoderm

Question 22

What are the 4 layers of the epidermis?

Answer 22

Superficial to deep
1. Keratin layer (stratum corneum) - devoid of nuclei.
2. Granular layer (stratum granulosum) - keratohyaline granules
3. Prickle cell layer (stratum spinosum) - polygonal cells 5 cell layers thick with eosinophilic cytoplasm joined by desmosomes
4. Basal cell layer (stratum basale) - single row of cells, contain melanin/melanocytes

Extra layer: Stratum lucidum (found between corneum and granulosum - found in palms/soles)

Question 23

How does entropion occur?

Answer 23

Laxity of tissue causes Relative dissociation of anterior lamella (skin + orbicularis) and posteiror lamella (tarsus, conjunctiva, lid retractors)

Leads to upward movement of anterior lamella and preseptal orbicularis muscle with weakness of lower lid retractors

There is horizontal lid laxity with medil and lateral canthal relaxation, leading to tarsal stretching