orbit :) , not the chewing gum

1. ???? 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.

2. • 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!!!

5. ANATOMY OF THE ORBIT
Presenter:- Pushkar Dhir
Moderator:- Dr.Neha Khanduja

6. 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.

8. • 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

9. • Entrance height-3.5cm
• Entrance width 4-4.5cm
DIMENSIONS

10. *Depthoforbitvariesfrom
4.4-5cm

11. BONY ORBIT
Composed of 7 bones-
1. Ethmoid
2. Frontal
3. Lacrimal
4. Maxilla
5. Palatine
6. Sphenoid
7. Zygomatic
.

12. 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)

13. 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.

14. 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 margin
CONTENTS: insertion of
tendinous pulley of
Superior Oblique
(In sme cases there is a
spicule of bone (Spina
trochlearis)
Nasolacrimal
sac & duct

15. 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.

17. Lacrimal bone is easily
penetrated during ENDO
DCR
*If maxillary
component is
predominenet
then its
difficult to do
EDNO DCR
1
2 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

18. • 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 imperfecta
Runs parallel to anterior lacrimal crest.

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

20. 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.

21. ORBITAL FLOOR
•Formed by-
•Orbital plate of maxilla (major)
•Orbital surface of Zygomatic bone (anterolateral)
•Orbital plate of Palatine bone
Shortest orbital wall Traingular

22. • 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.

23. 2. Blow out fracture- infraorbital nerves & vessels
usually get involved.
C/F:- Diplopia
Restricted movements(upgaze)
Paresthesia
Enophthalmos

24. ORBIT LATERAL WALL

25. • 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 tendon
2. Lateral rectus check
ligament.
3. Suspensory ligament of
lower eyelid (lockwoods
ligament)
4. Orbital septum
5. 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.

26. 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

27. ORBITAL FISSURE & FORAMINA

28. *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,exopht
halmos,ptosis
*Manner of involvement of nerves helps to
predict the site and extent of the lesion.
Divisions of III’rd nerve ± VI’th nerve
Annulus of Zinn (Purely intraconal lesion)
III’rd, IV’th and VI’th nerve
Entire length of the fissure involved
IOF/Sphenomaxillary Fissure
1.Venous drainage from the inferior part of the orbit
to
the pterygoid plexus
2.neural branches from the pterygopalatine ganglion
3.zygomatic nerve
4. infraorbital nerve

29. Connective Tissue System of Orbit
1. 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.

30. 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.

31. 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. Abducent
4. Nasociliary
5. Ciliary ganglion
6. Ophthalmic artery
7. SOV
8. Central orbital fat
Applied Anat:-
1. 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

32. • Thanks for listening to anatomy of
D orbit!!!!!!...nt dis
one genius..
Comp: oh…m sry
Grrr…r u
sleepy…??? Put
the right slide
Comp: ok
The
ORBIT