4 Orbit Anat

8/4/2019 4 Orbit Anat

1/55

DR. PRITISH PATNAIK (presenter) DR. RITHESH K.B (moderator)


2/55

Of 7


3/55


4/55


5/55


6/55

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


7/55

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 #


8/55

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


9/55


10/55

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


11/55

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


12/55


13/55

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.


14/55


15/55


16/55

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


17/55


18/55


19/55


20/55


21/55


22/55

knowledge of limits of safe sub-periostealdissection mandatory


23/55

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


24/55

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


25/55


26/55


27/55

Spiral of Til laux


28/55


29/55


30/55


31/55


32/55


33/55


34/55


35/55

Orbicularis Oculi CN Vll inability to close eye

Levator palpebral superioris CN lll ptosis

Superior tarsal muscle sympathetic fibers partialptosis


36/55


37/55


38/55


39/55

Buckling Theory

RetropulsionTheory


40/55


41/55

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


42/55


43/55


44/55


45/55


46/55


47/55

Sub-ciliary Incision and dissection


48/55

Extended lower eyelid technique(used to obtain increased exposure of the lateral orbital rim)


49/55

Incision of the conjunctiva below the

tarsal plate

Incision through periosteum

Trans-conjunctival approach


50/55

Supraorbital brow incision


51/55

Upper eyelid incision


52/55

Upper Blepharoplasty approach


53/55

Lateral Canthotomy approach


54/55

Coronal approach


55/55

Documents

4 Orbit Anat