4 orbit anat
TRANSCRIPT
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DR. PRITISH PATNAIK (presenter) DR. RITHESH K.B (moderator)
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Of 7
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PARAMETERS MEAN DIMENSIONS
(mm)
Height of orbital margin 40
Width of orbital margin 35
Depth of Orbit 40-50
Interorbital distance 25
Volume of orbit
3
30 cm
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Surgical anatomy of the Superior wall (roof)
Roof is very thin, translucent, fragile
But reinforced
~laterally by the greater wing of sphenoid &~anteriorly by superior orbital margin
so . . . the # which involve frontal bone tend to pass towardsthe medial side
Junction of the Roof and medial wall close to cribriformplate so . . . CSF leaks into orbit or nose in #
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Surgical anatomy of the Medial wall
Thinnest (0.2 0.4 mm) and very fragile
Lamina Papyracea ~ paper thin so . . . Ethmoiditis isthe common cause of orbital cellulitis
Disruption due to NE # . . . Traumatic hypertelorism
Lateral displacement of the frontal process of the
maxillae in NOE #. . . Traumatic telecanthus
Sudden posterior displacement of the globe . . .Medial displacement of the orbital plate of the ethmoidbone
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Surgical anatomy of the Floor
Floor traversed by infraorbital groove canalForamen
These weaken the already thin floor
Medial to this most blow out # so infraorbital nerves &vessels mostly involved . Complete division is uncommon.
Origin of Inf. Oblique m. # . . . Diplopia
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Surgical anatomy of the Lateral Wall
Weakened by Sup. and Inf. Orbital fissures
FZ suture invariably involved in trauma to this region
Whitnallstubercle
about 11mm below FZ suture on the orbital surface ofzygoma
Gives atachment to 3 structures
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The pilot hole should be commenced 1.5 cm above the
FZ suture and 0.5 cm behind the rim.
The angulation should be posteriorly at 45
to the long axis of the skull
and inferiorly at 30 to the horizontal axis,
limiting the penetration to 0.75 cm.
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Superior Orbital Fissure Syndrome
Neurological disorder due to # of Sup Orbital fissure
Diplopia, paralysis of Extra-ocular mm., Exopthalmos,
ptosis
If blindness is present, it is Orbital apex Syndrome
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knowledge of limits of safe sub-periostealdissection mandatory
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Sub-periosteal dissection of 25mm from inferior rimshould limit the operative field
Dissection should be restricted to 25 mm posterior to theFZ suture
Exploration distance of 30mm from Sup. orbital rim is safe
High medial wall dissection places orbital apex and opticcanal at risk
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STRUCTURE LANDMARK MEAN DISTANCE(mm)
Inf. orbital Fissure
(mid-point)
Infraorbital foramen 24
Sup orbital fissure FZ suture 35
Sup orbital fissure Supraorbital notch 40
Optic canal Supraorbital notch 45
Optic canal Ant lacrimal crest 42
Ant ethmoidal
foramen
Ant. Lacrimal crest 24
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Spiral of Til laux
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Orbicularis Oculi CN Vll inability to close eye
Levator palpebral superioris CN lll ptosis
Superior tarsal muscle sympathetic fibers partialptosis
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Buckling Theory
RetropulsionTheory
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The goal of primary reconstruction of blow
out fractures is the restoration of mobility
and function of the globe along with elevation
of prolapsed soft tissues from the antrum to
correct cosmetic deformities
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Sub-ciliary Incision and dissection
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Extended lower eyelid technique(used to obtain increased exposure of the lateral orbital rim)
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Incision of the conjunctiva below the
tarsal plate
Incision through periosteum
Trans-conjunctival approach
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Supraorbital brow incision
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Upper eyelid incision
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Upper Blepharoplasty approach
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Lateral Canthotomy approach
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Coronal approach
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