OXFORD HANDBOOK ANAT & PHYSIO Flashcards
Interpalpebral fissure length
30 mm wide, 10 mm high (slight higher in women)
Resting position of upper and lowerlid
upperlid 2mm below superior limbus
lowerlid level with or above inferior limbus
Does eyelid skin has subcutaneous fat?
NO
how many lashes in upper and lowerlid?
Lashes are arranged 2-3 rows along lid margin,
above 150 on upper eyelid
75 on lower eyelid
Meibomian gland MGs in (upper and lower lid)
35 upper eyelids and 25 lower eyelids
name two horizontal canthal tendon
medial canthal tendon and lateral canthal tendons
medial canthal tendon arises from
ant lacrimal crest and post lacrimal crest
lateral canthal ligament inserts
Whitnalls tubercle (zygomativ bone)
and posteriorly with lateral check ligament
LPS originates from
Orbital apex and runs forward over superior rectus (SR) to the orbital rim
Conjunctiva (is what and comprise of)?
The conjunctival is a mucous membrane comprising non-keratinized epithelium, BM and stroma
Epithelium of palpebral conjunctiva?
Stratified squamous form. Contains mucin secreting goblet cells and cypt of henle
Sensation of lowerlid (nerves)
Infraorbital nerve (Vb)
Medial canthal region: infratrochlear branch of nasociliary (Va)
Sensation of upper lid (nerves)
lacrimal, supraorbital and supratrochlear nerves (Va)
Innervation of orbicularis, LPS and muller muscles
Orbicularis CN7, LPS CN3, Muller sympathetic system
Arterial supply of lids
supply by three arcades form anastomoses btwn medial palpebral artery ( terminal branch of ophthalmic artery) and lateral palpebral artery (lacrimal artery)
Marginal arcade upper and lower lid mm
upperlid 2mm above margin and lowerlid 4mm below the margin
Venous Drainage Eyelid
superficial temporal vein - laterally
ophthalmic and angular vein - medially
Lymphatic drainage
parotid glands- laterally
submandibular glands- inferiorly
anterior cervical chain inferomedial
how many ducts run from the orbital lobe of lacrimal gland
12
lacrimal gland parasymphathetic innervation schematic
superior salivary nucleus (pons) - greater petrosal n - synapse at pterygopalatine ganglion - zygomatic n - lacrimal n - lacrimal gland
lacrimal puncta (location and diameter)
located 6mm lateral to medial canthus/ diameter 0.3mm
superior and inferior canaliculi parameter length and width
vertical part (ampulla : 2mm long 3mm wide)
horizontal part (8mm long 2 mm wide)
common canaliculi parameter
2mm long
common canaliculi parameter
2mm long
lacrimal sac parameter
12mm in length
lacrimal sac fossa
posterior to medial canthal tendon
lateral to ethmoid sinus
lacrimal duct parameter
18 mm runs parallel to nasojugal fold (inferolaterally)
fist 12 mm lies in bony nasolacrimal canal
last 6mm within mucous membrane of lateral wall of nose
which meatus lacrimal duct drains into
inferior meatus via ostium lacrimale
valves in nasolacrimal system (2)
Rosenmuller (entry to lacrimal sac)
Hasner (exit from nasolacrimal duct)
how many glands of krause?
28
how many glands of wolfring?
3
% of tears drained via superior and inferior canaliculus
70% inferior 30% superior
cornea act as/function
1) clear refractive surface
2) protective barrier to infection and trauma
cornea horizontal diameter
11.7mm
cornea vertical diameter
10.6mm
cornea shape (ant and pos)
anterior elliptical
posterior circular
corneal stroma accounts % of corneal thickness
90%
corneal proteoglycan substances (2)
1) chondrotin sulfate
2) keratan sulfate
corneal transparency
1) active deturgence
- endothelium is relative permeable
-stroma swelling pressure
-water passthrough homonally aquaporin eg AQP1
2) regular orientation and spacing of stromal collagen fibres
radii of curvatuve of cornea
anterior surface 7.7mm and posterior surface 6.8mm
