Eyelids (M1) Flashcards
location of upper eyelid
extend from conjunctival fornix to superior orbital rim
location of lower eyelid
extend from conjunctival fornix to nasojugal and palpebromalar sulci
location of lateral canthus
medial to lateral orbit rim.
lies on globe
palpebral fissure
opening between UL and LL.
horizontally: about 30 mm
vertically: about 10 mm
location of medial canthus
at medial orbital rim.
separated from globe by lacrimal lake
vertical palpebral fissure equation
VPF = MRD-1 - MRD-2
marginal reflex distance-1 (MRD-1) : distance between corneal reflex and UL
marginal reflex distance-2 (MRD-2) : distance between corneal reflex and LL
normal MRD1 and MRD 2 distance
MRD-1: 4-4.5 mm
MRD-2: >5 mm
qualities of eyelid skin
folds easily, very flexible –> important for blinking.
thinnest skin in the body
differences in eyelid and eyebrow skin
- dermis is thinner in eyelid
- dermis has less adnexal structures in eyelid
- minimal hypodermis in orbital region and absent in tarsal region
what is the composition and function of the tarsal plate
composition: dense connective tissue
function: give eyelid structure and rigidity
location of superior tarsus
extends from eyelid margin to superior palpebral sulcus
location of inferior tarsus
extends from eyelid margin to inferior palpebral sulcus
tarsal plate attachments
medial and palpebral ligaments (aka. canthal tendons).
superior tarsus: levator aponeurosis and superior tarsal muscle (Muller’s muscle)
inferior tarsus: capsulopalpebral fascia and inferior tarsal muscle
composition of orbital septum
sheet of dense connective tissue
general location of orbital septum
entire rim of orbit to tarsal plate
orbital septum UL attachments
becomes thickening of periosteum at superior orbital rim.
distal fibers merge with levator aponeurosis about 3-5 mm above tarsal plate
orbital septum LL attachments
becomes thickening of periosteum at inferior orbital rim.
distal fibers merge with capsulopalpebral fascia several mm below tarsal plate
function of orbital septum
separates eyelids and lacrimal sac from orbit to prevent infections from entering the orbit and also holds fat in place
composition of orbicularis oculi muscle
skeletal muscle
function of orbicularis oculi muscle
protractor of UL and LL.
contraction closes lids
origination and insertion of orbicularis oculi muscle
origination: medial orbital rim (maxillary and lacrimal bones)
insertion: lateral palpebral ligament
2 regions of the orbicularis oculi muscle
orbital and palpebral
2 regions of palpebral region
preseptal and pretarsal
fiber type, location, and contraction of orbital region
fiber: concentric
location: orbital rim to forehead, temple, and cheek
contraction: closes eyelids tightly, depresses eyebrows
location of preseptal region
in front of orbital septum
fiber type, location, and contraction of palpebral region
fiber: superior and inferior semilunar
location: lateral palpebral ligament across eyelid to medial palpebral ligament
contraction: closes eyelids gently
location of pretarsal region
in front of tarsal plate
composition of levator palpebral muscle
skeletal muscle
2 areas of pretarsal region
riolan’s muscle and horner’s muscle
antagonist of orbicularis oculi
levator palpebrae: innervated by CN VII - opens eye
frontalis muscles: innervated by CN VII - raises brow
function of levator palpebral muscle
main retractor of UL
what is levator palpebral muscle anterior to
superior rectus
antagonist of levator palpebral muscle
orbicularis oculi muscle
composition of tarsal muscle (Mullers muscle)
smooth muscle
function of tarsal muscle
accessory retractor of ULs and LLs.
contraction opens eyelids
origination and insertion of tarsal muscle UL
origination: levator muscle, about 10 mm above tarsus
insertion: superior border of tarsus / 2-5 mm below
origination and insertion of tarsal muscle LL
origination: capsulopalpebral fascia
insertion: lower border of tarsus
composition of capsulopalpebral fascia
connective tissue sheet
function of capsulopalpebral fascia
main retractor of LLs
capsulopalpebral fascia location
arise from Lockwood’s ligament and sheath of IR and IO.
course up to fuse with orbital septum 4-5 mm below tarsus –> forms common fascial sheet
capsulopalpebral fascia attachments
lower border of tarsus, muscle fibers of orbicularis oculi, and skin
capsulopalpebral fascia attachments to skin
inferior palpebral sulcus.
- fold/groove 5 mm below LL margin
- divides eyelid into tarsal and septal regions
- less marked than superior sulcus
where is palpebral conjunctiva
thin, transparent membrane that lines the underside of lids
cells and glands in the palpebral conjunctiva
goblet cells
accessory lacrimal glands of krause and wolfring
3 layers of the eyelid
anterior lamella:
- skin
- orbicularis oculi
middle lamella:
- orbital septum
- retractor muscles
posterior lamella:
- tarsal plate
- palpebral conjunctiva
grey line
divides anterior and posterior lamallae
location: between meibomian gland openings and eyelashes
surgical landmark for anterior border of Riolan’s muscle
location and function of eyelashes
location: ciliary portion
function: protect eye with blink response - shield from outside
glands in eyelid margin
glands of Zeis
- holocrine, sebaceous
- secrete sebum
- lubricate eyelid margin
glands of Moll
- apocrine, sweat
- secrete sweat
- function: unknown
lacrimal papilla/puncta
papilla: mound of tissue
- location: lacrimal portion
puncta: hole in center of papilla
- beginning of nasolacrimal drainage system
mucocutaneous junction
line of marx.
location: ciliary and lacrimal portion of eyelid margin
transition zone b/t palpebral conjunctiva and skin
lid wiper region
location: ciliary and lacrimal portion of eyelid margin, posterior to mucocutaneous junction
elevated strip of palpebral conjunctiva
meibomian gland orifices
location: ciliary portion of eyelid margin - in a row
function: secretes oils (lipids) onto skin in front of mucocutaneous junction whenever you blink
what is the general function of the eyelid
protect the globe:
- stimulation of sensory nerves –> contraction of orbicularis oculi
- eyelid protracts to protect the globe
