???? D FORGOTTEN STORY????

• When I awoke in hospital in Brighton I was told:• 'You must have an operation on your right eye.' ,,I was greatly surprised. • Apparently a splinter had passed from the windscreen and entered my eye.

Mr. David , the surgeon, was summoned to perform an emergency operation., he did good job• but afterwards I learnt that I had lost the lens of the eye, • it having dissolved through injury, and • The pupil of the eye had been stitched up, leaving me practically without vision. • The eye was also out of alignment.• It took me a long time to realize I had virtually lost the use of one eye, but even then, never for an

instant did I consider I might not be able to play cricket again. With a contact lens in my injured eye I found I could get about 90 per cent vision. The only trouble was it made me see TWO of everything.

• What might have happened that day??• Which all structures got damaged in orbit??• Who is HE??? Is he really important!!!

??????*any guesses*?????

A TIGER WITH A SINGLE EYE!!!

ANATOMY OF THE ORBIT

Presenter:- Pushkar DhirModerator:- Dr.Neha Khanduja

INTRODUCTION

• Quadrilateral pyramid shaped Bony cavities situated one on either side of root of nose.

• Major functions –1. Provide the socket for the rotatory movements of

the eye 2. Protect the eyeballs.

• Medial wall- parallel & approximately 2.5cm away

• Lateral wall-90 degree.

• Medial with lateral- 45 degree.

• Orbital axis- 22.5 degree, Divergent, Forwards and laterally.

22.5

Optical Axis

Orbital Axis

• Entrance height-3.5cm• Entrance width 4-4.5cm

DIMENSIONS

*Volume- slightly less than 30cc

*Dep

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*Len

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Entrance width 4-4.5cm

BONY ORBITComposed of 7 bones-

1. Ethmoid2. Frontal3. Lacrimal4. Maxilla5. Palatine6. Sphenoid7. Zygomatic

.

Orbital RIM• Superior orbital rim -> frontal bone.

• Inferior orbital rim -> maxillary bone medially and zygomatic bone laterally.

• Medial orbital rim -> Frontal process of maxilla

• Lateral orbital rim -> Zygoma

• In Medial 1/3rd of Superior orbital rim

Supraorbital notch.(supraorbital nerve & artery passes to forehead)

Orbital Roof

• 1.Orbital plate of Frontal bone & 2.Lesser wing of sphenoid.

• Relations- anterior cranial fossa (frontal lobe & meninges),frontal sinus, frontal nerve, trochlear nerve and supraorbital artery.

Landmarks-1.Fossa for lacrimal gland. 2. Fovea or trochlear fossa.3.Supraorbital notch. 4. Optic Foramen(+nt in lesser wing)

Applied anat :-Defect in roof- pulsatile proptosis due to transmission of CSF pulsation to orbit.

•FOSSA FOR THE LACRIMAL GLAND-•LOCATION: behind the zygomatic process of the frontal bone

TROCHLEAR FOSSA (FOVEA)LOCATION: 4 mm from the orbital marginCONTENTS: insertion of tendinous pulley of Superior Oblique

(In sme cases there is a spicule of bone (Spina trochlearis)

Nasolacrimal sac & duct

Cribra orbitalia:- apertures apparent on the medial side of anterior portion of the lacrimal fossa- for veins from diploë to the orbit ; Best marked in the fetus and infant.

At JUNCTION OF THE ROOF AND MEDIAL WALL, the suture line lies in proximity to CRIBRIFORM PLATE of ethmoid RUPTURE of dura mater CSF enter orbit/nose.

Medial Orbital Wall

Lacrimal bone is easily penetrated during ENDO DCR

*If maxillary component is predominenet then its difficult to do EDNO DCR

12 3

4

Fronto-ethmoidal suture line:- dissection done above this line will lead to cranial cavity

Ant.& Post. lacrimal crest

Weber`s Suture

Branches of infraorbital artery pass via this groove to supply the nasal mucosa.Bleeding may occur 4m these vessels during DCR surgeries

• Front - Backwards- Frontal process of Maxilla, Lacrimal bone , Orbital plate of Ethmoid (Largest), Lesser wing of sphenoid.

Applied anatomy-

1. Thinnest portion of wall - Lamina papyracea (it is component of ethmoid bone). Fractured in blow out fractures.

(Thick posteriorly at sphenoid and anteriorly at lacrimal crest.)

2. Infections and neoplasms of ethmoid sinus-orbital cellulitis and proptosis.

3. Weber`s Suture :- Also known as sutura longitudinalis imperfectaRuns parallel to anterior lacrimal crest.

Ant. & Post.ethmoidal sinus is located 24mm &36 mm from anterior lacrimal crest respectively.Ant. & Post. Ehtmoidal arteries pass through it.

CLINICAL SIGNIFICANCE OF MEDIAL WALL

• Medial wall extremely fragile (presence of ethmoidal air cells and nasal cavity)

• Accidental lateral displacement of medial wall- traumatic hypertelorism

• Medial wall provides alternate access route to the orbit through the sinus

• Ethmoid- Thinnest bone of the orbit- Vascular connections with ethmoid sinus through foramina- Inflammation in the ethmoid sinus spreads readily to the orbit

• Tumours of the nasal cavity can breach the lamina papyracea to involve the orbit

• Lacrimal bone can be easily penetrated during endoscopic DCR

• During surgery, hemorrhage is most troublesome due to injury to ethmoidal vessels.

ORBITAL FLOOR

•Formed by-• Orbital plate of maxilla (major)• Orbital surface of Zygomatic bone (anterolateral)• Orbital plate of Palatine bone

Shortest orbital wall Traingular

• Landmarks- Inferior orbital fissure, end backward in pterygopalatine fossa. Infraorbital groove (post) and canal (ant)

• Applied anatomy-1. As it is roof of maxillary sinus- 0.5-1mm thick. Maxillary carcinoma invading up in

orbit may cause proptosis.

2. Blow out fracture- infraorbital nerves & vessels usually get involved.

C/F:- DiplopiaRestricted movements(upgaze)ParesthesiaEnophthalmos

ORBIT LATERAL WALL

• Thickest and strongest. Greater wing of sphenoid

and zygomatic bone forms it

• Applied anatomy- Anterior half of globe is vulnerable to lateral trauma.

• Landmarks-

Whitnall’s tubercle- zygomatic bone.

4-5 mm behind lateral orbital rim & 1 cm below fronto-zygomatic suture line.

Structure attaching:-1. Lateral canthal tendon2. Lateral rectus check

ligament.3. Suspensory ligament of

lower eyelid (lockwoods ligament)

4. Orbital septum5. Lacrimal gland fascia

*C/S:- Tubercle is spared in maxillary resection in CA, as it gives attachment to lockwood etc, can lead to diplopia if resected.

2.The Spina recti lateralis :— • Its a small bony projection situated on the inferior margin of the SOF at the

junction of its wide and narrow portions. • Gives rise to lateral rectus muscle.

3.Zygomatic Groove• Extent:-From the anterior end of the inferior orbital fissure to a foramen in the

zygomatic bone.• Contents:

- Zygomatic nerve- Zygomatic vessel.

• Lateral wall protects ONLY THE POSTERIOR HALF of the eyeball, hence palpation of retrobulbar tumours is easier.

• Frontal process of zygoma & zygomatic process of frontal bone protect the globe from lateral trauma- known as facial buttress area.

• Just behind the facial buttress area, is the zygomaticosphenoid suture, which is the preferred site for lateral orbitotomy.

C/S of Lateral Wall

ORBITAL FISSURE & FORAMINA

*Also k/a Spenoidal fissure

*Structure Passing :-(Superior LFT + NAO)

*C/S :- Tolosa Hunt Syndrome (Inflammation of the superior orbital fissure and apex ophthalmoplegia &venous outflow obstruction.

*Superior Orbital Syndrome(Rochon-duvigneaud Syndrome)- # of SOF CN involves Diplopia,ophthalmoplegia,exophthalmos,ptosis

*Manner of involvement of nerves helps to predict the site and extent of the lesion.

Divisions of III’rd nerve ± VI’th nerveAnnulus of Zinn (Purely intraconal lesion)

III’rd, IV’th and VI’th nerveEntire length of the fissure involved

IOF/Sphenomaxillary Fissure1.Venous drainage from the inferior part of the orbit to the pterygoid plexus2.neural branches from the pterygopalatine ganglion3.zygomatic nerve4. infraorbital nerve

Connective Tissue System of Orbit1. Periorbita/Orbital Periosteum *Loosely adherent to the bones *Sensory innervation by branches of V’th

nerve

Applied Anat:- Tumors and pus collected in the subperiosteal space cause thickening of subperiosteum and can cause proptosis and elevated

IOP.• Eg- dermoid cyst, epidermoid cyst,

mucocele, subperiosteal abcess, myeloma, osteomatous tumors, haematoma and fibrous dysplasia.

• Plain X- rays most useful in diagnosis.

2. Orbital septal system Includes the connective tissue septa

which are suspended from the periorbita to form a complex radial and circumferential interconnecting slings.

3. TENON’S CAPSULE( FASCIA BULBI OR BULBAR SHEATH)• Dense, elastic and vascular connective tissue that surrounds the globe (except over the cornea).• Begins anteriorly at the perilimbal sclera, extends around the globe to the optic nerve, and fuses with the

dural sheath and the sclera.• Separated from the sclera by periscleral lymph space, which is in continuation with subdural and subarachnoid

spaces

• Applied anatomy-1. After enucleation, implants are placed within tenon’s capsule or posterior to it within muscle cone.2. Inflammatory pseudotumor cause florid tenonitis to cause proptosis.

ORBITAL SPACES

CENTRAL SPACE

Within the muscle cone

SUBTENONS SPACE

Space b/w sclera & sub

tenon capsule

Contents-1. ON and its meninges.2. Sup and inf- oculomotor nerve.3. Abducent4. Nasociliary5. Ciliary ganglion6. Ophthalmic artery7. SOV8. Central orbital fat

Applied Anat:-9. Tumors- axial proptosis. Eg-

cavernous haemangioma, solitary neurofibroma, neurilemmoma, schwannoma, ON glioma

*Pus collected in this space is drained by incision of Tenon’s capsule through the conjunctiva-*Site for drug instillation

• Thanks for listening to anatomy of

D orbit!!!!!!...nt dis one genius..

Comp: oh…m sry

Grrr…r u sleepy…??? Put the right slideComp: ok

The ORBIT