ORBIT & OCULAR ADNEXAE - Eyelids Flashcards
What is the grey line of the eyelid? What does it divide?
Gray line divides the eyelid margin into the anterior lamina and posterior lamina
What is the difference between the gland of zeiss and the gland of moll in terms of
1. Location
2. Lobularity
3. Function
- Zeiss : at the margin of the eyelid,
Moll: between cilia (eyelash) and anterior lid margin - Zeiss: unilobular
Moll: unbranched spiral shape - Zeiss: modified sebaceous gland that produces sebum to prevent eyelashes from becoming dry and brittle
Moll: apocrine sweat gland
What is the horizontal and vertical measurement of the palpebral fissure?
horizontal - 30mm
vertical - 9-11mm
What is a mongoloid slant? Which strabismus pattern does it exhibit
Elevation of lateral canthus > 2mm
Pseudo A pattern strabismus
What conditions have mongoloid slant?
Down’s syndrome
Noonan’s syndrome
What conditions have Anti-mongoloid slant? What strabismus pattern?
Treacher collin syndrome
Coffin lowry syndrome
Zygomatic maxillary complex fracture
Pseudo V pattern strabismus
What are the 7 layers of the eyelid from outside to inside?
- Skin - v thin loosely adhered to muscle
- Subcutaneous areolar tissue - only fat
- Striated muscle layer (orbicularis + LPS)
- Submuscular areolar tissue
- Fibrous layer (tarsal plate and orbital septum)
- Non-striated muscle layer - Muller’s muscle
- Conjunctiva
What are the two parts of the orbicularis muscle? What is their function?
- Orbital part - forced closure of eyelid
- Palpebral part - gentle closure of eyelid
Which layer consists of the nerves and vessels of the eyelid? What does this layer connect with?
Submuscular areolar tissue
Communicates with striatum of scalp - dangerous area of scalp and can act as communication for pus/blood between two areas
What is the tarsal plate?
Dense fibrous tissue of the eyelid giving strength and firmness, has meibomian glands embedded within it
What is the upper and lower tarsal height?
Upper : 10mm
Lower: 5mm
How many meibomian glands are there?
20-30 on each lid
What do meibomian glands produce?
Sebaceous glands (like Zeiss glands) Produce lipids (meibum) that forms the outer layer of tear film to stop evaporation
What is attached to the superior tarsal border? (2)
What structure is attached below the superior tarsal border?
1.Orbital septum and muller’s muscle
2. LPS aponeurosis attaches 3-4mm below,
What is attached to the inferior tarsal border? (3)
Orbital septum
capsulopalpebral fascia
inferior palpebral/tarsal muscle (lockwood ligament) which connects to the inferior rectus