Anatomy of eyelids and clinical significance of the various structures.

1. ANATOMY OF EYELIDS
-DR. SHIBASHIS DEB
1st Year PGT, Ophthalmology.
Silchar Medical College.

2. The Eyelids:
The eyelids are thin folds of skin, on either side, that covers
and protects the human eyes.
They act as a shutter mechanism and play very important role
in protection of the eyeballs from trauma and excessive light,
maintaining the tear film, blink reflex and in cosmetic beauty
of the eye.

3. GROSS ANATOMY OF EYELIDS:
The eyelids are mobile folds of tissue which are placed in front of the
eyeballs. The gross anatomy of the eyelids is as follows:
1. Extent: The upper eyelid extends from the eyebrows, in a
downward direction, to end in a free margin. This forms the superior
border of the palpebral fissure.
The lower eyelid extends from a free margin, the lower
border of the palpebral fissure, proceeds downwards and merges
with skin of the cheek.
IN the primary gaze position, the upper eyelids cover
1/6th of the cornea(2mm from upper corneal margin) and the lower
eyelids just touches the cornea.

4. 2. Lid Folds: The skin of the eyelids are not smooth and have folds
on them, known as the lid folds.
The superior lid fold is present in the upper eyelid. It is formed by
the insertion of a few fibers of the levator palpebrae superioris
which retracts the skin. It divides the upper eyelid into the - orbital
part and tarsal part.
The inferior lid folds are less distinctly marked and is formed due
to the fibrous slips of fascia around inferior rectus, which are
inserted into the skin.
There are 2 other folds:
a. Naso-jugal skin fold.
b. Malar skin fold.

5. 3. Canthi: The canthi are the two angular area where the upper and
the lower eyelids meet. They are called the medial and lateral canthi
respectively.
The lateral canthus is in touch with the eyeball. In the
position of primary gaze, it has angle of 30◦ and an angle of 60◦ in
eyes wide gaze.
The medial canthus is rounded and separated from the
globe by the lacus lacrimalis. The medial canthus contains the
caruncle and plica semilunaris.

6. 4. Lid Margins: The eyelid margins are 2mm in width and are nearly
flat.
The lid margins have several important structures associated with it.
The most important is the lacrimal papilla which has the lacrimal
puncta at its centre. This medially situated elevation in the lid margin
divides it into 2 parts : -
a. The medial lacrimal portion. This portion is
devoid of eyelashes and glands.
b. The lateral ciliary portion. This has a
rounded anterior portion, a sharp posterior border and an
intermarginal strip. This strip contains the a grey line, the junction
between skin and conjunctiva.

7. 5. Eyelashes: The eyelashes are arranged in the ciliary portion of
the eyelid margin, in 2-3 rows.
The upper eyelashes are 100-150 in number and the lower lashes
are 50-75 in number. They do not interlace when the eyelids appose.
Each cilium has a lifespan of 3-4 months.
The lashes lack errectores and are embedded in the the fibrous
tissue that binds the the ciliary margin of tarsus to the overlying
skin. Each follicle is surrounded by dense plexus of vessels and
nerves.
The modified sebaceous glands of Zeis and sweat gland of Moll
empty into the infundibulum of each ciliary canal.

8. 6. Palpebral aperture: It is the elliptical space between the upper
and lower eyelid margins.
Dimensions: Horizontal Vertical
At birth 18-21 mm 8 mm
At adult 28-30 mm 9-11 mm
Anatomical variation: The lateral canthus maybe is slightly
(<2mm) higher then the medial canthus.
The greater elevation of lateral canthus results in a mongoloid
slant. A lower level of lateral canthus results in a antimongloid
slant.

9. Structural Anatomy :
The eyelids consists of the following layers from outside to inside:
1. Skin
2. Subcutaneous areolar tissue layer.
3. Striated muscle layer.
4. Submuscular areolar tissue layer.
5. Fibrinous layer.
6. Non-striated muscle fibre layer.
7. Conjunctiva.

11. 1. Skin:
• It is elastic and thinnest in the body (thickness 0.05mm). Nasal
part is smooth while temporal part has fine hairs.
• The epidermis is well-formed with 6-7 layers of stratified
squamous epithelium.
• The basal layer contains numerous unicellular sebaceous glands
and typical eccrine sweat glands.
• The dermis is composed of dense connective tissue of elastic
fibres, blood vessels, lymphatics and nerves.
2. Subcutaneous areolar tissue:
• Does not containing fat.
• Non-existent near the ciliary margin, lid folds and at medial and
lateral angles.

12. 3. Striated muscle layer:
This layer consists of the following muscles:
a. Orbicularis oculi – both upper and lower lid.
b. Levator palpebrae superiors – upper lid.
Orbicularis oculi:
This muscle is divided into two distinct parts – the
orbital (peripheral) part and palpebral (central) part.
Orbital part :
Origin (Medial) Insertion
(Lateral)
Function
1. Medial palpebral lig.
2. Upper orbital margin medial
to supraorbital notch.
3. Maxillary process of frontal
bone.
4. Lower orbital margin medial
to infraorbital foramen.
1. Lateral palpebral
raphae.
2. Superiorly, skin
of eyebrows.
1. Forced closure of
eyelids.
2. Pulls eyebrows
downwards.

14. Palpebral part:
It is subdivided into – preseptal and pretarsal fibres.
Preseptal fibres:
Pretarsal fibres:
Origin Insertion
1. Medial palpebral lig. (ant.)
2. Lacrimal fascia
3. Posterior lacrimal crest.
1. Lateral palpebral raphae.
Origin Insertion
1. Medial palpebral lig. (ant.)
2. Lacrimal fascia
3. Posterior lacrimal crest
1. Lateral canthal tendon,
inserted over Lateral
orbital tubercle of Whitnall.

15. Muscle of Horner (tensor tarsi) Muscle of Riolan
It plays an important part in drainage
of tear secretion via lacrimal pump
system.
It helps in maintaining a close
relation of the eyelids with the globe
(Lamination effect).

16. LEVATOR PALPEBRAE SUPERIORS:
The LPS, present in the upper eyelids, is the
major muscle for elevating them.
It is a striated muscle which lies beneath the subcutaneous areolar
tissue, and acts as the primary elevator of the eyelids along with –
Frontalis (accessory elevator in extreme upgaze) and Muller’s muscle
(1st 2mm elevation and long term adjustments).
Gross Anatomy:
The LPS muscle has 2 parts – a. the fleshy part
b. the tendinous aponeurosis
Fleshy Part Tendinous Part
• 40 mm long.
• Runs horizontally.
• From origin of LPS upto Superior
Transverse Lig. Of Whitnall.
• 15mm long annd 30mm wide.
• Runs vertically.
• From Lig. Of Whitnall to insetion of
LPS.

17. Origin:
• At the Apex of the orbit
• From the under-surface of the Lesser wing of Sphenoid.
• Above the Annulus of Zinn, by a tendinous process, that merges
with the belly.

18. Course of LPS:
Fleshy part:
a. Runs forwards between the Roof of Orbit and
Superior Rectus.
b. Widens as it proceeds and on reaching the Superior
Transverse Lig. Of Whitnall, it descends vertically posterior to
orbital fat wedge.
Tendinous part:
a. As the LPS approaches the Septum Orbitale it
fans out into LPS aponeurosis, and tapers into medial and lateral
horns.
b. The medial horn passes over the reflected head
of superior oblique and fuses with medial canthal tendon.
c. The lateral horn passes though the lacrimal
gland and divides it into – orbital (larger) and palpebral parts and
inserts into lateral canthal tendon.

19. Fig: Course of LPS and its relation with Whitnall’s lig. and Lacrimal
gland.

20. Insertion of LPS:
The aponeurosis of LPS passes through the septum orbitale and then forwards
and downwards till the tarsal plates. It widens into 2 major attachments.
1. The anterior collagen fibers attach to the septa between the orbicularis
muscle fibers, at the level of upper border of tarsal plate. Few fibers insert
into the pre-tarsal skin.
2. The posterior part attach to the anterior surface of tarsus, 3-4mm below its
superior border.
3. A few fibers attach posteriorly into the superior conjunctival fornix.

21. Superior Transverse Lig. Of Whitnall:
• The function of LPS depends on the integrity of this ligament.
• It extends from trochlear pulley system (medially) to the capsule of
orbital part of lacrimal gland (laterally).
• This is formed fibrous sheath farms from the condensation of superior
sheath of LPS and reflected head of Superior Oblique.
• At the level of this lig. the LPS bends and moves downwards from its
horizontal direction.

22. 4. Submuscular areolar tissue
1. It is a layer of loose connective tissue present between the
orbicularis muscle and the fibrous layer.
2. It splits the eyelid into – anterior lamina and posterior lamina.
3. In upper eyelid it is traversed by the LPS which divides it into two
spaces – a. pretarsal space.
b. preseptal space.
Clinical importance:
1. The nerves and vessels of the lids lie in this layer, so anaesthesia
for lids is given in this plane.
2. In upper eyelid, it is connected superiorly with subaponeurotic
startum of scalp – dangerous area of scalp.

23. Pretarsal space:
1. It is a small space which appears fusiform in a vertical section.
2. Bounded by – LPS (anteriorly) and Tarsal plate (posteriorly).
Clinical significance – The peripheral arterial arcade is present here.
Preseptal space:
1. It appears triangular is vertical section.
2. Bounded by – Orbicularis oculi (anteriorly) and Orbital septum
(posteriorly).
Preseptal cushion of fat:
1. It is crescent-shaped pad of fat.
2. Bounded by – Orbicularis oculi (anteriorly); to which it is firmly
adherent; and Orbital septum (posteriorly).

24. Fig: Submuscular areolar space with its spaces.

25. 5. Fibrous layer:
The fibrous layer consists of – Tarsal plate (centrally) and Septum
Orbitale (peripherally). It also includes the medial and lateral
palpebral ligaments.
Tarsal Plate:
Tarsi are firm plates of dense fibrous tissue that form the skeleton of
the eyelids giving them shape and firmness.
Size: The tarsi 29mm long and 1mm thick. The upper tarsus is 10mm
in height and lower tarsus is 4-5mm.
Borders: The free border are straight while the attached borders are
convex.
Superior border of upper tarsus gives attachment to– Septum orbitale
and Muller’s muscle.
Inferior border of lower tarsus gives attachment to – Orbital septum,
Capsulopalpebral fascia and inferior palpebral muscle.

26. Surfaces: The tarsal plates have 2 surfaces.
Anterior surface, it is convex and seperated from orbicularis muscle
by loose areolar tissue. In the upper eyelid, the LPS gets attached to
the anterior surface 3-4mm from the upper border. This area of 3-
4mm is the potential pretarsal space.
Posterior surface, is concave and is lined by firmly adherent
conjunctiva.
Extremities: The lateral ends of the tarsi are attached to the
Whitnall’s tubercle by the lateral palpebral lig. and the medial ends
are attached to the Anterior Lacrimal crest and frontal process of
Maxilla by the medial palpebral lig.
The tarsal plate contains the Meibomian glands embedded within its
substance.

27. Fig: Tarsal plates and the attached structures.

28. SEPTUM ORBITALE
It is a thin, floating membrane of connective tissue which takes part
in the movements of the eyeball.
Attachments: Centrally, it becomes continuous with the convex
borders of the tarsi.
Peripherally, it is attached to the orbital margins at
a thickening called Arcus marginale.
Structures piercing through septum orbitale:
The septum orbitale is important as several structures pierce
through it including blood vessels and nerves.
From medial to lateral:
1. Superior and inferior palpebral arteries.
2. Infratrochlear N. and Dorsal nasal A. (upper septum)
3. Supratrochlear N. and A. (upper septum)
4. Supraorbital N. and A. (upper septum)
5. Lacrimal N. and A. (upper septum)
6. Expansion of inferior rectus (lower septum)

30. Fig: Structures passing through the Septum Orbitale.

31. Clinical Importance of Septum Orbitale:
The Septum Orbitale forms a barrier against spread of infection to
the deeper structures of the eye.
An infection, which is in front of the
septum, preseptal cellulitis, has
better prognosis then a deeper
infection and is associated with less
number of complications.

33. 6. Layer of Non-Striated Muscle fibres:
This layer consists of smooth muscle fibres of Muller.
Origin: Upper eyelid – Inferior terminal striated fibres of LPS.
Lower eyelid – Expansion of the inferior rectus.
Insertion: The Muller’s muscles get inserted in the orbital margin of
the tarsal plate.
Nerve supply: Supplied by sympathetic nerve fibres.
7. Conjunctiva:
The posterior-most layer of the eyelid is formed by the palpebral
conjunctiva. It extends from the mucocutaneos junction at the lid
margin to the conjunctival fornix.
It is firmly adherent to the posterior surface of the tarsal plate and
Muller’s muscle.

34. Fig: Muller’s muscle and Palpebral conjunctiva. (upper lid)

35. Gland Location Opening Secretion
Meibomian
gland.
Stroma of tarsal plate.
Arranged vertically parallel
to each other, 20-30 in each
lid.
Single row on the lid
margin between
posterior border and
grey-line.
Oily in nature
(sebum).
Gland of
Zeis.
Follicles of cilia, eyelid and
caruncle.
Opens directly into
the eyelash follicle.
Usually 2 per cilium.
Oily in nature.
Gland of
Moll.
Eyelids, between the cilia.
Unbranched spiral in shape.
Terminate seperately
between 2 lashes or
into the ducts of Zeis
gland.
Sweat.
Glands of
Wolfring.
Upper border of superior
tarsus
Lower border of inferior
tarsus.
Into inner surface of
eyelid
Aqueous.
(contribute to
tear film)
Glands of the Eyelid:

36. Vessels and Nerves of the Eyelid:
Arterial Supply: Upper eyelid, supplied by 2 arterial arcades –
a. Marginal arterial arcade, formed by anastomosis
of the medial and lateral palpebral arteries.
b. Superior arterial arcade, formed by the superior
branches of the medial palpebral artery.
Lower eyelid, has a single marginal arterial arcade
formed similar to the upper eyelid.
Venous Supply: The venous drainage of eyelids are arranged in 2
sets of venous plexus:
a. Pretarsal venous plexus: Drains mainly into
subcutaneous veins – Angluar vein -> Internal jugular vein medially
and Superficial temporal V. and Lacrimal V. -> External jugular vein
laterally.
b. Post-tarsal venous plexus: Drains mainly into
the Ophthalmic veins.

38. Lymphatic drainage of the eyelids:
Lymphatic Vessels
Medial Group
Superficial medial
channel
Superficial
Submandibular
L.N.
Deep medial
channel
Deep
Submadibular
L.N.
Lateral
Group
Deep lateral
channel
Deep Parotid
L.N.
Superficial
lateral channel
Superficial
Parotid and
Preauricular
L.N.

39. Lymphatic Drainage:
Medial Group : A. Superficial : i) Medial ½ of lower lid, ii) Medial
¼ of upper lid and iii) medial commissure.
B. Deep : i) Medial 2/3rd of conjunctiva of lower lid
and ii) caruncle.
Lateral Group : A. Superficial : i) Lateral ½ of lower lid and ii)
Lateral ¾ of upper lid.
B. Deep : i) Lateral 1/3rd of conjunctiva of lower
lid and ii) entire conjunctiva of upper lid.

40. Fig: Schematic diagram of lymphatic drainage of eyelids.

41. Nerve Supply:
Motor Nerve: 1. Zygomatic branch of Facial N. – Orbicularis muscle.
2. Oculomotor N. – Levator Palpebrae Superioris.
Sensory Nerve: Derived from branches of the 1st and 2nd divisions
of the Trigeminal N.
Upper lid: supraorbital, supratrochlear,
infratrochlear and lacrimal branches.
Lower lid: infraorbital, infratrochlear and orbital
branches.
Sympathetic Nerve: supply Muller’s muscle, the vessels and the
glands of the skin.
Arrangement: The nerves are arranged in the submuscular plane
(between orbicularis and the tarsal plates). This is the plane of
anaesthesia of eyelids.

42. Embryology of the eyelids:
• Reduplication of surface
ectoderm
• 2nd month of gestation.
• Contain mesoderm –
gives rise to muscles.
• Lids are fused at 2nd
trimester and separate at
7th month of IUL.
• Molecular biology and
genetics:
• cell migration – FGF10,
TGF-α, Activin B and
HB-EGF modulate
downstream BMP4
signaling, ERK cascade
and JNK/c-JUN.
•Wnt/β-catenin – inhibit
and regulate eyelid fusion.

43. Congenital Anomalies of the Eyelid:
Condition Description Treatment
Epicanthal folds Vertical folds of skin over the
canthal area.
Utilize the excess horizontal skin
to make up the vertical deficit.
Telecanthus Increased distance between
medial canthi (>30mm)
Shortening of medial canthi by
transnasal wiring with
transposition of flaps.
Epiblepharon Excess of skin of medial part of
eyelids with vertical eyelashes
Excision of redundant skin with
adjacent orbicularis.
Blepharophimosis Horizontal and vertical size of
palpebral fissure is reduced
Mustarde’s procedure.
Euryblepharon Incresed horizontal palpebral fissure,
downward dispalcement of lateral
canthus, ectropion of lateral 1/3rd of
lid
Canthoplasty
Coloboma of lid Full-thickness lid margin defect
due to absence of fusion.
Tanzel procedure – large defect
Cutler-Beard procedure – severe cases
Hughe procedure – lower lid defect
Ankyloblepharon Variable portions of the lids are
fused together
Lateral side – Canthoplasty
Medial side – lacrimal app
reconstruction
Cryptophthalmos Failure of seperation of lids at
4th to 6th week IUL
As anterior segment agenesis is a
rule, no treatment for restoration.