Eyelid

Anatomy of eyelid

1. Eyelid

2. Eyelids are mobile tissue curtains placed in front of eyeballs Function: - Act as shutters protecting eyes from injuries and excessive light - Help spread tear film over cornea and conjunctiva - Help in drainage of tears by lacrimal pump system - Contribute to the facial feature Information regarding the state of wakefulness and attention

3. CANTHI Two lids meet each other at medial and lateral angles  Medial angle is rounded and 5mm medial to the eye ball. The medial canthus is about 2mm higher than the lateral canthus.

4. PALPEBRAL APERTURE Elliptical space between the upper and lower lid Measure about 10-11mm vertically and 28-30mm horizontally

5. LID MARGIN 2mm broad Divided by punctum into two parts - Medial , lacrimal portion : rounded and devoid of lashes or glands - Lateral , ciliary portion : * rounded anterior border * sharp posterior border * intermarginal strip * grey line

6. STRUCTURE 1 . Skin 2 . Subcutaneous areolar tissue 3 . Layer of striated muscle orbicularis muscle - three portions :orbital, palpebral , lacrimal - closes eyelids, supplied by zygomatic branch of facial nerve levator palpebrae superioris - arises from apex of orbit - inserted on skin of lid, tarsal plate, conjunctiva of superior fornix - raises upper lid, supplied by branch of oculomotor nerve

7. 4. Submuscular areolar tissue - nerves and vessels lie in this layer - to anaesthetise 5 . Fibrous layer - central tarsal plate - peripheral septum orbitale 6 . Layer of non-striated muscle fibres - palpebral muscle of Muller 7 . Conjunctiva - palpebral conjuctiva - marginal, tarsal, orbital

8. GLANDS OF EYELIDS Meibomian glands or tarsal glands - present in stroma - arranged vertically - 30 to 40 in upper lid and 20 to 30 in lower lid - modified sebaceous glands Glands of Zeis - open into follicles of eyelashes Glands of Moll - modified sweat glands situated near hair follicles - open into hair follicles or into ducts of Zeis Accessory lacrimal glands of Wolfring - upper border of tarsal plate

9. Blood supply ARTERIES: -In humans, the eyelids are supplied with blood by two arches on each upper and lower lid . - The arches are formed by anastamoses of the lateral palpebral arteries and medial palpebral arteries, branching off from the lacrimal artery and ophthalmic artery, respectively.

10.  VEINS: These are arranged in two plexus: a post-tarsal which drains into ophthalmic veins and a pre- tarsal opening into subcutaneous veins. LYMPHATICS : Arranged as post-tarsal and pre-tarsal. Those from lateral half of the lids drain into preauricular lymph nodes and those from the medial half of the eyelids drain into submandibular lymph nodes.

11. NERVE SUPPLY Motor nerves Facial - orbicularis muscle Oculomotor - levator palpebrae superioris Sympathetic fibres – Muller’s muscle Sensory nerves Upper lids : lacrimal , supraorbital and supratrochlear branches of trigeminal nerve Lower lid : infraorbital nerve with infratrochlear branch

12. Thank you