Anatomy of the eyelids

1. A n atomy of the Eyelids

2. Introduction to the Eyelids An eyelid is a thin fold of skin that covers and protects an eye . Protects against the dust, injury and excessive light by its closure. It spread the tears on the eye surface to keep it moist, since the cornea must be continuously moist. Also involve into exit of tears into drainage system at medial canthus . They keep the eyes lubricated when asleep .

3. GROSS ANATOMY

4. GROSS ANATOMY Each eyelid is divided by a horizontal furrow ( sulcus ) into an orbital and tarsal part. uper sulcus formed by the aponneurotic fibers of levator muscle into the skin. Lower sulcus is due to connection of orbicularis muscle with skin.

5. Position of eyelid When eye is open, the upper lid covers about 1/6th of the cornea & the lower lid just touches the limbus . When eye closed, it covers the whole cornea

6. Palbebral fissure or aperture There is the elliptical space b/w the upper and the lower lid called Palbebral fissure. When the eyes are opened, it measures about 10-11mm vertically in the centre and about 28-30mm horizontally.

7. Canthi or angles of eyelids The two lids meet each other at medial and lateral angles(or outer & inner canthi ). Lateral canthus is directly in contact with the eye ball Medial angle is rounded and 5mm medial to the eye ball. The medial canthus is about 2mm higher than the lateral canthus .

8. Medial canthus Medially eyelids are separated by a small triangular space called lacus lacrimalis . In the centre there is pinkish elevation called caruncula lacrimalis . On the lateral side of the caruncula there is semilunar skin fold called plica semilunaris

9. THE LID MARGIN It is About 2mm broad and is divided into two parts by punctum . The medial 1/6 th , the lacrimal portion is rounded and devoid of lashes or glands. The lateral 5/6 th of eyelid margin is the ciliary portion consist of rounded anterior border, a sharp posterior border and an inter-marginal strip.

10. Conti… 5mm from the medial angle there is small elevation called papilla lacrimalis On the papilla there is small hole called punctum lacrimalis . Punctum varies from 0.4 to 0.8mm in size It is the part of lacrimal apparatus for the drainage of the tears.

11. Eye lashes Short curved hairs are present on the margins of the eye lids from the lateral angle of the eye to the papilla. More numerous in upper lid and curved upward And those of lower lid curved downward. In front of the posterier edge of the margin of the lids there are the openings of the tarsal gland seen as yellowish line on the inner surface of the everted eye lid.