Eyelids Flashcards
Insertion
The point of attachment of a tendon or ligament onto the skeleton or or their part of the body
The palpebral fissure
Gap or aperture between the eyelids
What are eyelids/palpebrae
Covered by skin externally
Covered by conjunctiva internally
Function of eyelid
Shield from minor injuries
Remove foreign objects (blinking)
Control light entry (improve distance vision-depth of field)
Contribute to and sustain tear film
Palpebral furrows
External folds in skin marking tarsal and septal join
Much individual variation
Epicanthal fold
Fold of skin in young occidental and young and old Asians
Present in the foetus or all races
Tarsal portion
Contains tarsal plates. Extend along the lid margins across the width of the lids- contains many glands
Tarsal (Meibomian) glands
Long thin glands embedded inside tarsal plates
Collecting ducts empty to inner edge of eyelids
Secretion has high lipid content
Oily secretion lines kids and prevents movement of aqueous tears onto kid skin
Also lipid villager on tear film limits aqueous evaporation
What can problems with lid movement (levator especially) cause
Ptosis or lid droop
What is ptosis
Drooping of the upper eyelid
Orbital septum
Flexible connective tissue that retains orbital fat
What are tarsal plates made of
Connective tissue
What does the orbital/ septal portion include
Skin, orbicularis muscle, orbital septum, preaponeurotic fat pad, levator aponeirosis insertion, mullers muscle, conjunctiva
What does tarsal portion consist of
Skin, orbicularis muscle, tarsal plate, conjunctiva
Tarsal glands (meibomian)
Excretory ducts every 1mm
More glands in upper plate
Eyelid movement
Palpebral fodder closed by orbicularis oculi muscles
Muscles of the face that enter lids anterior to other lid muscles and run in arcs
What is levator muscle linked to
Broad flat tendon called levator aponeurosis attached to front tarsal plate
What is upper edge of levator muscle attached to
Sphenoid bone inside orbit
Where does inferior tarsal muscle insert
Directly into lower edge of inferior tarsal plate
Where does eyelid have ill-defined origin in connective tissue
near inferior oblique and rectus muscles
To widen palpebral fissure upper tarsal plate pulled up by
Levator muscle
Superior tarsal muscle (mullers muscle)
What is lower tarsal plate pulled down by
A single inferior tarsal muscle
Where does superior tarsal muscle (millers) run behind
The levator aponeurosis and insets directly into upper edge of superior tarsal plate
What do upper end join
The origin of levator aponeurosis
Where do orbicularis muscles insert
Medial palpebral ligament and lateral palpebral ligament
What are medial palpebral ligament and lateral palpebral ligament
Medial and lateral canthal tendons
What does chronic overreaction of pre-septal orbicularis result in
Entropion
Eye lashes scratch the cornea
Palpebral
Part of a continuous sheet
Limbal (lumbar) epithelium
Continuous with corneal epithelium
Plies semilunaris
Vestigial ‘third eyelid’
Lacrimal caruncle
Contains accessory lacrimal and sebaceous glands
Epithelium in conjunctiva contains:
Epithelial cells
Langerhans cells that provide an immune response
Lymphocytes
Substantia propria (stroma) bull bar in conjunctiva contains :
Many types of immunocompetent cells
Connective tissue
Vascular network
Nerve supply
Glands in conjunctiva :
Goblet cells that secrete mucus into the tear film
About 50 accessory lacrimal glands
Function of conjunctiva :
Production of the mucus component of tear film
Immunological defence protects ocular surface from infection
