Head and Neck: Orbital cavity

Bones that form the orbital margin

frontal bone

zygomatic bone

maxillary bone

Roof

frontal

lesser wing of sphenoid

lateral wall of the orbit

zygomatic

greater wing of sphenoid

floor of the orbit

zygomatic

maxillary

palantine

Medial wall of the orbit

maxillary

lacrimal

ethmoid

sphenoid

periorbitum

lines the bony orbit as periostium covers the bones of the rest of the skeleton

highly innervated!

the periorbitum serves as

an anchor for muscles, facia, ect

periorbitum provides

lining for movement without friction

helps prevent spread of infetion/trauma to cranial cavoity

vessles and nerves travel here

Intraconal

within the cone of the EOMs

Extraconal

outside the cone of EOMs

Why is there fat in the orbital cavity

protection/cushion (can absorb shock from trauma)

keeps eye in proper position/alignment in the orbit

provides low-friction enviorment for movement

Fasscia

a thin sheath of fibrous tissue enclosing a muscle or other region

functions of fascia

maintain eye position/support orbital cavity

viscoelastic forces wich EOMs must overcome to move the eye and keep it in that new position

Tenon's capsule

fascia which extend from limbus cornea to optic nerve

the eye moves within Tenon's capsue where there is a frictionless space

potential space (episcleral space)

tenon's capsule is located

anteriorly between conjunctiva and sclera

Tenon's capsule continues posteriorly to

merge with sheath of optic disc

Tenons capsule separates

orbital fat from contact with the sclera

Fascia bulbi

tenons capsule

Fascia orbitalis

covering of the extraocular myscles

Check ligaments

Medial

lateral

Medial check ligament

makes sure we fo not move eye too far out

lateral check ligament

makes sure eye does not move too far in

fascial band between EOMS

levator and superior rectus

inferior rectus and inferior oblique

suspensory ligament of Lockwood

hammock-like sheet of dense Connect. tissue that runs from lacrimal bone to zygomatic bone

Orbital Septum

a fibrous membrane that forms the anterior boundary of the orbit

extends from the orbital rim

is a continuation of the periobitum

the orbital septum attatches to the

Arcus marginalis

Arcus marginalis

a thickened periosteal condensation at the junction of the orbital rim and the septum

orbital septum: superiorly blends with

the aponeurosis of levator

Muscles of the eyelid

Orbicularis Oculi

Levator

Orbicularis oculi innervation:

CN VII (temporal and zygomatic branches)

Orbicularis Oculi parts

Palpebral portion

Orbital portion

Palpebral portion

pretarsal

preseptal

gentle blinking

Mucle of Riolon

cilliary

lid globe congruity

Failure of lid-globe congruity leads to

ectropion

epiphora

keratitis

pars lacrimalis

Horner's muscle

posterior lacrimal crest to tarsal plates

places puncta in optimal position (draws lid medially ) to drain tears from lacrimal lake

levator palpebrae superioris innervation

CN III

Levator origin

at apex of orbit

inferior surface of lesser wing of sphenoid bone

just superior to superior rectus

levator isertion

into skin

tarsal plate

superior fornix conjunctiva

levatpr action

elevates lid and conjunctica

Superior Tarsal muscle

smooth mucle

elvates lid and conjunctiva

Superior tarsal muscle innervation

sympathetic

Superior tarsal muscle origin

inferior surface of the levator palpebrae superioris muscle

Superior tarsal muscle insertion

Superior fornex conjunctiva

tarsal plate

Superior tarsal muscle dysfunction

small lid ptosis

lid ptosis can be cause by

cranial nerve III - Levator (larger)

sympathetic - Superior tarsal muscle of Mueller (smaller)

If you have a ptosis with dilated pupil

cranial nerve III palsy

parasymapthetics are not working

lid ptosis with a constricted pupil

Horners syndrome

sympathetics are not working

Structures traversing the superior orbital fissure outside the tendinous annulus

Lacrimal nerve

Frontal nerve

Trochlear nerve IV

Structures traversing the superior orbital fissure inside the tendinous annulus

Oculomotor nerve (superior)

ocultomoror nerve (inferior)

abducens nerve (CN VI)

nasociloary nerve