Dr. Ankit Mohapatra

DEPARTMENT OF PUBLIC HEATH DENTISTRY 1

INTRODUCTION

EMBRYOLOGY

ANATOMY

BONY ORBIT

WALLS OF ORBIT

MUSCLES OF THE ORBIT

NERVE SUPPLY OF THE ORBIT

VASCULAR SUPPLY

LACRIMAL SYSTEM

ORBITAL FAT

ORBITAL INJURIES AND INFECTION

REFERENCES

2

The Orbit is a pyramidal, bony cavity in the facial skeleton

with its base anterior and its apex posterior.

The orbits contain and protect the eyeballs and their muscles,

nerves, and vessels, together with most of the lacrimal apparatus.

The bones forming the orbit are lined with periorbita

(periosteum of the orbit), which forms the fascial sheath of the

eyeball .

The periorbita is continuous at the optic canal and superior

orbital fissure with the periosteal layer of dura.

The periorbital is also continuous over the orbital margins and

through the inferior orbital fissure with the periosteum covering

the external surface of the skull (pericranium).

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Orbit is the anatomical space bounded:

Superiorly – Anterior cranial fossa

Medially - Nasal cavity & Ethmoidal air sinuses

Inferiorly - Maxillary sinus

Laterally - Middle cranial fossa & Temporal fossa

4

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EMBRYOLOGY

Orbital walls- derived from cranial neural crest cells which

expand to form:

Fronto nasal process

Maxillary process

Lateral nasal process + Maxillary process = medial,

inferior and lateral orbital walls

Capsule of forebrain forms orbital roof 6

Early in the human development

eyes point almost in the opposite

direction.

As the facial growth occurs, the

angle between the optic stalks

decreases and is ~68˚ in an adult.7

EMBRYOLOG

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OSSIFICATION

Endochondral

Intra-Membranous

8

EMBRYOLOGY

Frontal, Zygomatic, Maxillary and Palatine bones- Intra

membranous origin

First bone- Maxillary (at 6 wks of intrauterine life)

- develops from elements in the region of the canine tooth

- secondary ossification centers in the orbito nasal and

premaxillary regions

Other bones develop at around 7 wks of intrauterine life9

EMBRYOLOGY

Sphenoid bone- both enchondral and intra membranous origins

Lesser wing of the sphenoid- 7 wks (Enchondral)

Greater wing of the sphenoid- 10 wks (Intra membranous)

Both wings join- 16 wks

Ossification is complete at birth (except orbital apex)

10

EMBRYOLOGY

ANATOMY OF THE ORBIT

11

FORAMEN-

An opening inside the body of humans which typically allows

muscles, nerves, arteries, veins, or other structures to connect

one part of the body with another

FOSSA-

It is a depression or hollow, usually in a bone, such as the

hypophyseal fossa (the depression in the sphenoid bone)

RE-CAP………

12

FISSURE –

A deep furrow, cleft, or slit; a gap between bones or

bony elements.

ORBITO

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Orbit / eye socket is roughly

irregular four sided pyramid

located on either side of root

of nose.

Base - at the orbital opening

Apex - at optical canal

Axis directed posteriorly

and medially

Medial walls - nearly

parallel

Medial and lateral walls

makes an angle of 45

degrees

25mm

13

The orbit is related

On its superior side to the anterior cranial fossa and

usually to the frontal sinus.

Laterally to the temporal fossa in (anterior) and to the

middle cranial fossa (posterior).

On its inferior side to the maxillary sinus.

Medially to the ethmoidal and the anterior extent of the

sphenoidal sinuses.14

• Height of orbital margin - 40 mm

• Width of orbital margin - 35 mm

• Depth of orbit - 40-50 mm

• Inter orbital distance - 25 mm

• Volume of orbit - 30 cm3

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COMPOSED OF:

7 Bones:

Ethmoid

Frontal

Lacrimal

Maxillary

Palatine

Sphenoid

Zygomatic

16Right orbit

BOUNDARIES

17

4 WALLS

ROOF FLOORMEDIAL WALL

LATERAL WALL

BOUNDARIES

18

OR

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ROOF Underlies Frontal sinus and

Anterior cranial fossa

Formed by-

1. Frontal bone (Orbital plate)

2. Lesser wing of Sphenoid

Triangular

Faces downwards, and slightly forwards

19Left orbit

Concave anteriorly, almost flat posteriorly

The anterior concavity is greatest about 1.5 cm from the orbital

margin & corresponds to the equator of the globe.

Thin, translucent and fragile (except the lesser wing of the

sphenoid)

20

ROOF

LANDMARKS

• 1. FOSSA FOR THE LACRIMAL GLAND-

LOCATION:

behind the zygomatic process of the frontal bone

CONTENTS:

lacrimal gland

some orbital fat

21

ROOF

SYNDROME:

A syndrome is a set of medical signs and symptoms that are

correlated with each other and, often, with a specific disease.

22

2. TROCHLEAR FOSSA (FOVEA)

LOCATION:

4 mm from the orbital margin

CONTENTS:

insertion of tendinous pulley of Superior Oblique

o sometimes (≈10%) surmounted by a spicule of bone (Spina

trochlearis)

o Extremely rarely trochlea completely ossified cracks

easily

SURFACE ANATOMY:

Palpable just within the supero-medial angle

23

ROOF

3. SUPRAORBITAL NOTCH:

LOCATION:≈15 mm lateral to the superomedial angle

TRANSMITS:

- Supraorbital nerve

- Supraorbital vessels

SURFACE ANATOMY:

- At the junction of lateral 2/3rd and medial 1/3rd

- About two finger breadth from the medial plane

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ROOF

Right orbit

4. OPTIC FORAMEN:

LOCATION:

- Lies medial to superior

orbital fissure

- at the apex

- Present in the lesser wing

of sphenoid

TRANSMITS:

- Optic nerve with its

meninges

- Ophthalmic artery 25

ROOF

Left orbit

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

Frontosphenoidal suture:

- between frontal and the lesser wing of the sphenoid

- usually obliterated in the adults 26

ROOF

CLINICAL SIGNIFICANCEThin and fragile

Easily fractured by direct violence (penetrating orbital injuries)

Frontal lobe injury

27

ROOF

Reinforced

- Laterally- greater wing of sphenoid

- Anteriorly- superior orbital margin

So, fractures tend to pass towards medial side

At junction of the roof and medial wall, the suture line lies in proximity to cribriform plate of ethmoid

rupture of dura mater

CSF escapes into orbit/nose/both28

ROOF

MEDIAL WALL

Thinnest orbital wall

Formed(Antero-posteriorly)

1. Frontal process of

Maxilla

2. Lacrimal bone

3. Orbital plate of Ethmoid

4. Body of the sphenoid

Almost parallel to each other 29Left orbit

LANDMARKS

LACRIMAL FOSSA:

- Formed by:

- frontal process of maxilla

- lacrimal bone

- Boundaries:

- Anterior- anterior lacrimal crest

- Posterior- posterior lacrimal crest

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- Dimensions-

- Length≈ 14 mm

- Depth≈ 5 mm

- Continuous below with bony nasolacrimal canal

- Content-

- Lacrimal sac

31

MEDIAL

WALL

ANTERIOR LACRIMAL CREST*-

- upward continuation of the inferior orbital margin

- Surface anatomy-

- Palpable along the medial orbital margin (anteriorly)

POSTERIOR LACRIMAL CREST*-

- downward extension of the superior orbital margin

- Surface anatomy-

- Palpable along the medial orbital margin, posterior to the lacrimal fossa

*significant landmarks in lacrimal sac surgery 32

MEDIAL WALL

FRONTO ETHMOIDAL SUTURE LINE

- Marks the approximate level of ethmoidal sinus roof

- Breach of this suture may open the frontal sinus, or the

cranial cavity

- Anterior and posterior ethmoidal foramina are present in

the suture line

33

MEDIAL WALL

Anterior ethmoidal foramen

- 20-25 mm posterior from the anterior lacrimal crest

- Opens in the anterior cranial fossa at the side of the

cribriform plate of ethmoid

- Transmits-

- anterior ethmoidal nerve & vessels

34

MEDIAL WALL

Posterior ethmoidal

foramen

- 32-35 mm posterior from anterior

lacrimal crest

- 7 mm anterior to the anterior rim of

optic canal

- Transmits

- posterior ethmoidal

nerve & vessels

35

MEDIAL

WALL

Left orbit

WEBER’S SUTURE

Lies anterior to lacrimal fossa

Also known as sutura longitudinalis imperfecta

Runs parallel to anterior lacrimal crest

Branches of infraorbital artery pass through this groove to

supply the nasal mucosa

Bleeding may occur from these vessels during DCR

surgery.

DCR- Dacryo Cysto Rhinostomy (surgery is a procedure

that aims to eliminate fluid and mucus retention within the

lacrimal sac)36

MEDIAL WALL

FLOOR

• Shortest orbital wall

• Roughly triangular

• Formed by-

• Orbital plate of maxilla

(major)

• Orbital surface of Zygomatic

bone (anterolateral)

• Orbital plate of Palatine

bone

37

Right orbit

Bordered laterally by inferior orbital fissure and medially

by maxillo ethmoidal suture

Overlies maxillary sinus

38

FLOOR

LANDMARKS

Infraorbitalgroove

Infraorbitalcanal

Infraorbitalforamen

39

Approximately equal to 4 mm inferior to the inferior

orbital margin

Transmits

- Infraorbital nerve

- Infraorbital vessels

FLOOR

CLINICAL SIGNIFICANCE BLOW OUT FRACTURES:

Fractures of the orbital floor

Infraorbital nerves and vessels are almost invariably involved

Patient presents with

Diplopia

Restricted movements(upgaze)

Paresthesia

Enophthalmos

40

FLOOR

LATERAL WALL

Formed by-

1. Zygomatic bone

2. Greater wing of sphenoid

Thickest orbital wall

Separates orbit from-

Middle cranial fossa

Temporal fossa

At an angle of about 90° with

each other 41Right orbit

LANDMARKS LATERAL ORBITAL

TUBERCLE OF

WHITNALL:

- 4-5 mm behind the

lateral orbital rim

- 2 mm inferior to the

frontozygomatic

suture line

42

LATERAL

WALL

Right orbit

CLINICAL SIGNIFICANCE

In resection of maxilla, the Whitnall’s tubercle is spared,

otherwise

Damage to Lockwood’s ligament

Inferior dystopia of eye ball

Diplopia43

LATERAL

WALL

LOCKWOOD’S LIGAMENT:

The suspensory ligament of eyeball (or Lockwood's ligament)

forms a hammock stretching below the eyeball between the

medial and lateral check ligaments and enclosing the inferior

rectus and inferior oblique muscles of the eye.

LATERAL WALL

44

ZYGOMATIC GROOVE:

- EXTENT:

- From the anterior end of the inferior orbital fissure to a

foramen in the zygomatic bone

- CONTENTS:

- Zygomatic nerve

- Zygomatic vessels

45

LATERAL WALL

CLINICAL SIGNIFICANCE

Anteriorly, superior margin of inferior Orbital fissure joins suture between zygomatic and greater wing of sphenoid (line of relative weakness)

extends to frontozygomatic suture

Frequently involved in zygomatic bone fracture 46

LATERAL WALL

ORBITAL MARGINS

47

SUPERIOR ORBITAL MARGIN

- formed by- Frontal bone

- concave downwards, convex forwards

- sharp in lateral 2/3rd ,rounded in medial 1/3rd

- at the junction- supraorbital notch (sometimes foramen)*

- *Site for nerve block.

48

49

Sometimes-

o Arnold’s notch/foramen

Present medial to supraorbital notch

Transmits

medial branches of supraorbital nerve & vessels

o Supraciliary canal

Near the supraorbital notch

Transmits

nutrient artery

a branch of supraorbital nerve to frontal air sinus

50

SUPERIOR ORBITAL

MARGIN

SURFACE ANATOMY:

- Well marked prominence

- More prominent laterally than medially

- Eyebrow corresponds to the margin only in a part

- Head- under the margin

- Body- along the margin

- Tail- above the margin

51

SUPERIOR ORBITAL

MARGIN

LATERAL ORBITAL MARGIN:

- formed by

- zygomatic process of frontal

- the zygomatic bone

- strongest portion of margin

52

CLINICAL SIGNIFICANCE

Lateral orbital rim is recessed on its deep aspect ≈ 0.75 cm above

the rim margin to accommodate the lacrimal gland

Prone to fracture

53

LATERAL ORBITAL

MARGIN

Narrowest and weakest part- frontozygomatic suture

Prone for separation following blunt trauma

54

LATERAL ORBITAL MARGIN

INFERIOR ORBITAL MARGIN:

Formed by-

- Zygomatic

- Maxilla

- suture between the two is sometimes marked by a

tubercle- felt 4-5 mm above the infraorbital foramen

SURFACE ANATOMY:

- Palpable as a sharp ridge, beyond which the finger can pass

into the orbit55

CLINICAL SIGNIFICANCE

At the junction of lateral 2/3rd & medial 1/3rd just within the rim-

small depression- origin of Inferior oblique muscle.

Prone to fracture

Disruption of Inferior oblique muscle

Diplopia

Penetrating injuries may severe lacrimal passages

56

INFERIOR ORBITAL MARGIN

Diplopia:

It is commonly known as double vision, is the

simultaneous perception of two images of a single object that

may be displaced horizontally, vertically, diagonally (i.e., both

vertically and horizontally), or rotationally in relation to each

other. It is usually the result of impaired function of

the extraocular muscles (EOMs), where both eyes are still

functional but they cannot converge to target the desired object

57

MEDIAL ORBITAL MARGIN:

- Formed by

- Frontal process of maxilla (anterior lacrimal crest)

- Lacrimal bone (posterior lacrimal crest)

58

FISSURES

AND

FORAMINA

59

OPTIC CANAL

Leads from the middle cranial fossa to the apex of the orbit

Orbital opening- vertically oval

In the middle- circular (≈5mm)

Intracranial- horizontally oval

Length ≈ 8-12 mm

- Attained at 4-5 years of age

Boundaries-

- Medially- Body of the sphenoid

- Laterally- Lesser wing of the sphenoid60Right orbit

Directed- forwards, laterally and downwards

Distance between

Intracranial openings≈ 25mm

Orbital openings≈ 30mm

Transmits-

Optic nerve & its meninges

Ophthalmic artery

61

OPTIC

CANAL

CLINICAL SIGNIFICANCE

Optic nerve glioma or Meningioma may lead to

unilateral enlargement of Optic canal

62

OPTIC CANAL

Strut view of Optic

Canal

(Normal)

CT-Scan showing lesion in Left

optic nerve

SUPERIOR ORBITAL FISSURE Also known as Sphenoidal fissure

Lateral to the optic foramen

at the orbital apex

comma-shaped gap between the roof

and the lateral wall

Bounded by- Lesser and greater wings

of the sphenoid

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Left orbit

64

SUPERIOR ORBITAL

FISSURE

Right superior orbital fissure

22 mm long

Largest communication between the orbit and the

middle cranial fossa

Its tip lies 30-40 mm from the frontozygomatic

suture

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SUPERIOR ORBITAL

FISSURE

Lateral superior part of the fissure is narrower than the

medial inferior part.

- At the junction of the two lies spina recti lateralis

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SUPERIOR ORBITAL

FISSURE

SPINA RECTI LATERALIS:

• This is a small bony projection situated on the inferior

margin of the superior orbital fissure at the junction of its

wide and narrow portions.

• It may be pointed, rounded, or grooved, and gives origin to a

part of the lateral rectus muscle, but it is produced mainly by

a groove which lodges the superior ophthalmic vein.

• This groove is prolonged upwards, then runs anterior to the

spine.

• Gives origin to a part of Lateral Rectus

SUPERIOR ORBITAL

FISSURE

67

LANDMARK Annulus of Zinn

- Spans both superior orbital fissure & the optic

canal

- Gives origin to the four recti muscles

68

SUPERIOR ORBITAL

FISSURE

CLINICAL SIGNIFANCE Inflammation of the superior orbital fissure and

apex may result in a multitude of signs including

ophthalmoplegia and venous outflow obstruction

TOLOSA HUNT SYNDROME

69

SUPERIOR ORBITAL

FISSURE

-A rare disorder characterized by severe and

unilateral headaches with extra ocular palsies, usually

involving the third, fourth, fifth, and sixth cranial nerves, and

pain around the sides and back of the eye, along with

weakness and paralysis (ophthalmoplegia) of certain eye

muscles.

*OPTHALMOPLEGIA - PARALYSIS OF THE

MUSCLES WITHIN OR SURROUNDING THE

EYE.

*PTOSIS – DROOPING OR FALLING OF UPPER

EYELID.

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Fracture at superior orbital fissure

Involvement of cranial nerves

Diplopia, Ophthalmoplegia*,

Exophthalmos, Ptosis,

SUPERIOR ORBITAL

FISSURE

A neurological disorder characterized

by exophthalmos, diplopia, and anaesthesia in regions

innervated by the trigeminal nerve, occurring with a traumatic

collapse of the superior orbital fissure

SUPERIOR ORBITAL SYNDROME(Rochon-Duvigneaud syndrome

SUPERIOR ORBITAL

FISSURE

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INFERIOR ORBITAL FISSURE

Also known as sphenomaxillary fissure

Between floor and the lateral wall

Bounded by-

o Medially- Maxilla and orbital process of palatine

o Laterally- Greater wing of the sphenoid

o Anterior aspect- closed by Zygomatic bone

72

Left orbit

Transmits-

- Venous drainage from the inferior part of the orbit to

the pterygoid plexus

- neural branches from the pterygopalatine ganglion

- the zygomatic nerve

- the infraorbital nerve

Closed in the living by the periorbita & the Orbitalis

muscle.

Serves as the posterior limit of surgical subperiosteal

dissection along the orbital floor 73

INFERIOR ORBITAL

FISSURE

CONNECTIVE TISSUE SYSTEM

Periorbita

Orbital septal system

Tenon’s capsule

74

PERIORBITA (ORBITAL PERIOSTEUM)

Loosely adherent to the bones

Sensory innervation by branches of V’th Cranialnerve

Fixed firmly at

- Orbital margins (Arcus marginale)

- Suture lines

- Various fissures & foramina

- Lacrimal fossa75

CLINICAL SIGNIFICANCE

Surgery in the orbital roof in the areas of fissures and

suture lines may be complicated by cerebrospinal fluid

leakage .

76

PERIORBITA

ORBITAL SEPTAL SYSTEM

Includes the connective tissue septa which are suspended

from the periorbita to form a complex radial and

circumferential interconnecting slings.

These septa surround Extraocular muscles, Optic nerve,

neuro-vascular elements and the fat lobules.

77

TENON’S CAPSULE

Also known as 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.78

CONTENTS OF THE ORBIT Eye ball

Muscles

4 Recti

2 obliques

Levator palpebrae superioris

Muller’s muscle (Musculus

orbitalis)

Nerves

Sensory- branches of V’th Nerve

Motor- III’rd, IV’th & VI’th Nerve

Autonomic- Nerves to the Lacrimal gland

Ciliary ganglion

79

Left orbit

Vessels

Arteries-

Internal carotid system- branches of ophthalmic artery

External carotid system- a branch of internal maxillary artery

Veins-

Superior ophthalmic vein

Inferior ophthalmic vein

Lymphatics-

none

Lacrimal gland

Lacrimal sac

Orbital fat

80

CONTENTS OF THE

ORBIT

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EYE BALL

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In total there are 7 muscles that move the eye in side the Orbit.

The following muscles help our eyes move around:

A. Levator palpebrae superioris

B. Four Recti Muscles-

-Superior Rectus

-Inferior Rectus

-Medial Rectus

-Lateral Rectus

C. Two Oblique Muscles-

-Superior Oblique

-Inferior Oblique

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LEVATOR PALPEBRAE SUPERIORIS

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This thin, flat elevator muscle of the superior eyelid

broadens into a wide aponeurosis as it approaches its distal

attachment to the tarsal plate. This muscle is the opponent

of the orbicularis oculi, the sphincter of the palpebral

fissure.

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LEVATOR

PALPEBRAE

SUPERIORIS

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Tarsal gland

Palpebral surface

Posterior margin

Anterior margin

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FOUR RECTUS MUSCLES

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•Superior rectus:

•Inferior rectus:

•Medial rectus:

•Lateral rectus:

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TWO OBLIQUE MUSCLES

•Superior oblique: Originates on the sphenoid bone and inserts

into the sclera deep to the superior rectus muscle.

•Inferior oblique: Originates on the anterior part of the orbital

floor and inserts onto the sclera deep to the lateral rectus muscle.

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The four recti arise from a fibrous cuff, the common tendinous

ring, that surrounds the optic canal and part of the superior

orbital fissure.

TENDINOUS RING

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OPTIC NERVE

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The optic nerve enters the orbit from the middle cranial fossa

by passing through the optic canal

It is accompanied by the ophthalmic artery, which lies on its

lower lateral side.

The nerve is surrounded by sheaths of pia mater, arachnoid

mater, and dura matter.

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It runs forward and laterally within the cone of the recti muscles

and pierces the sclera at a point medial to the posterior pole of

the eyeball.

Here, the meninges fuse with the sclera so that the subarachnoid

space with its contained cerebrospinal fluid extends forward

from the middle cranial fossa, around the optic nerve, and

through the optic canal, as far as the eyeball.

A rise in pressure of the cerebrospinal fluid within the cranial

cavity therefore is transmitted to the back of the eyeball

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ITCranial Nerve III (Occulomotor)

• It supplies all the extraocular muscles except the superior

oblique and the lateral rectus

• It also carries cholinergic innervation to the pupillary

sphincter and the ciliary muscle

• The CN III nucleus consists of several distinct, large

motor cell subnuclei, each of which subserves the extraocular

muscle it innervates

• The Edinger-Westphal nucleus provides the parasympathetic

preganglionic efferent innervation to the ciliary muscle and

pupillary sphincter

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• CN III usually divides into superior and inferior divisions

• The superior division of CN III innervates the superior rectus

and levator palpebrae muscles.

• The larger inferior division splits into three branches to supply

the medial and inferior rectus muscles and the inferior oblique.

• The parasympathetic fibers enter the inferior division, and

course through the branch that supplies the inferior oblique

muscle and join the ciliary ganglion.

• They synapse with the postganglionic fibers, which emerge as

many short ciliary nerves. 96

The Edinger–Westphal nucleus (accessory oculomotor

nucleus) is the parasympathetic pre-ganglionic nucleus that

innervates the iris sphincter muscle and the ciliary muscle.

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Cranial nerve IV has the longest intracranial course

The CN IV the only cranial nerve that is completely

decussated and the only motor nerve to exit dorsally from

the nervous system.

CN IV enters the orbit through the superior orbital fissure

outside the annulus of Zinn and runs superiorly to

innervate the superior oblique muscle

CRANIAL NERVE IV

(TROCHLEAR)

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The nucleus of cranial nerve VI is situated in the floor of

the fourth ventricle, beneath the facial colliculus, in the

caudal pons

CN VI runs below and lateral to the carotid artery and may

transiently carry sympathetic fibers from the carotid plexus

It passes through the superior orbital fissure within the

annulus of Zinn and innervates the lateral rectus muscle on

its ocular surface

CRANIAL NERVE VI (ABDUCENS)

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• The largest cranial nerve

• Possesses both sensory and motor divisions The sensory

portion subserves the greater part of the scalp, forehead, face,

eyelids, eye, lacrimal gland, extraocular muscles, ear, dura

mater, and tongue

• The motor portion innervates the muscles of mastication

through branches of the mandibular division

CRANIAL NERVE V (TRIGEMINAL)

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Ophthalmic

◦ Frontal

◦ Lacrimal

◦ Nasociliary

Maxillary

Mandibular

DIVISIONS OF CRANIAL NERVE V

101

OPTHALMIC NERVE

• The ophthalmic nerve, the first division of the trigeminal (fifth

cranial) nerve, is a wholly afferent nerve that supplies the globe

and conjunctiva, lacrimal gland and sac, nasal mucosa and

frontal sinus, external nose, upper eyelid, forehead, and scalp.

• It arises from the trigeminal ganglion which contains the cell

bodies of its sensory nerve fibers. It divides near the superior

orbital fissure into the lacrimal, frontal, and nasociliary nerves.

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• The lacrimal nerve proceeds along the superior border of the

lateral rectus and supplies the lacrimal gland, conjunctiva, and

upper eyelid.

• A communication with the zygomatic nerve (maxillary

division of trigeminal) carries some secretory fibers to the

lacrimal gland.

LACRIMAL NERVEN

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•The frontal nerve passes anteriorward on the levator palpebrae

superioris and divides into the supraorbital and supratrochlear

nerves.

•The supraorbital nerve leaves the orbit through the supraorbital

notch or foramen and supplies the forehead, scalp, upper eyelid,

and frontal sinus (the lower eyelid is supplied by the maxillary

nerve.)

•The supratrochlear nerve, more medial and much smaller,

supplies a small area of the forehead and upper eyelid

FRONTAL NERVEN

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• The nasociliary nerve is within the cone of muscles and is

therefore on a lower plane than the lacrimal and frontal nerves.

• The nasociliary nerve is the sensory nerve to the eyeball and is

accompanied by the ophthalmic artery.

• It courses anteriorward, inferior to the superior rectus, crosses

the optic nerve (usually superior to it), and is continued medially

as the anterior ethmoidal nerve.

• The nasociliary nerve gives off a communicating branch to the

ciliary ganglion, long ciliary nerves, the infra trochlear, and

posterior and anterior ethmoidal nerves.

NASOCILIARY NERVEN

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The ethmoidal nerves contribute branches to the

nasal cavity and external nose.

Sympathetic nerve fibers join the nasocillary

nerve after entering the orbit with the ophthalmic

artery. They will follow branches of the long

cillary nerves to the dilator pupillae muscle.

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CILIARY GANGLION

- Peripheral parasympathetic ganglion

- Lies between Optic nerve and Lateral Rectus muscle

- ≈1cm anterior to the optic foramen

- 3 posterior roots

- Sensory root

- Nasociliary Nerve

- Motor root

- Nerve to inferior oblique

muscle

- Sympathetic root

- Branches from internal carotid plexus 108

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Diagram showing Ciliary Ganglion.N.B- Opthalmic branch of Trigeminal Nerve is termed as V1

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VASCULAR SUPPLY TO ORBIT

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•An anastomosing network of vessels derived from the internal

and external carotid artery systems supplies the orbit.

•The major arterial supply to the orbit is the OPHTHALMIC

ARTERY (the first major branch of the internal carotid artery)

and the INFRA ORBITAL ARTERY.

OPTHALMIC ARTERY

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•The ophthalmic artery originates from the internal carotid as it

exits the cavernous sinus.

•The ophthalmic artery courses on the inferior aspect of the optic

nerve and enters the orbit through the optic canal.

•The artery gives off many branches with a significant amount of

variability.

In general, the branches of the ophthalmic artery can be divided

into 3 groups of vessels based on their target organs.

1. Ocular

2. Orbital

3. Extra orbital

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•The ocular branches include the central retinal artery, ciliary

arteries, and collateral branches to the optic nerve.

•The orbital branches are the lacrimal artery, muscular arteries,

and periosteal branches.

•Extraorbital branches include the posterior and anterior ethmoid

arteries, supraorbital artery, medial palpebral artery, dorsal nasal

artery, and supratrochlear artery.

•The orbital and extraorbital vessels further divide into branches

that anastomose with vessels from the external carotid artery

system.113

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•The zygomatic artery derives from the lacrimal artery and then

branches into temporal and facial divisions that anastomose with

branches of the superficial temporal artery.

•The lacrimal artery has a branch to the gland and a recurrent

meningeal branch, which returns to the middle cranial fossa.

•The lateral palpebral artery branches from the lacrimal artery to

supply a cascade of vessels in the eyelid and anastomose with

the medial palpebral artery.

•The medial palpebral artery is supplied by a combination of the

dorsal nasal artery and the angular artery, which comes from the

external carotid system114

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•The posterior and anterior ethmoid arteries pass through their

respective foramina in the frontal bone.

•The anterior ethmoid artery is the larger of the 2 arteries and

supplies the anterior and middle ethmoid air cells, the frontal

sinus, and the dura of the anterior cranial fossa via a meningeal

branch.

•The supraorbital artery supplies the muscles of the eyebrow and

forehead and has connection with the frontal branch of the

superficial temporal artery.

•The supratrochlear artery terminates in the scalp and is the

artery upon which paramedian forehead flaps for nasal

reconstruction are based.

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INFRA ORBITAL ARTERY

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•The infraorbital artery is a branch of the external carotid system

via the internal maxillary artery.

•The infraorbital artery branches from the internal maxillary

artery in the pterygopalatine fossa and enters the orbit through

the inferior orbital fissure to travel across the floor of the orbit in

the infraorbital sulcus.

•The infraorbital artery exits the skull at the infraorbital foramen

and forms a network with vessels of the facial artery and

zygomatic artery.

VENOUS SYSTEM

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Venous drainage of the orbit occurs through 2 major veins, the

SUPERIOR and INFERIOR OPHTHALMIC VEINS.

Venous drainage of the orbit, like its arterial supply, occurs

through an anastomosing network of internal and external

systems.

The orbital veins are valveless; therefore, direction of venous

drainage depends on pressure gradients.

Superior ophthalmic vein collects flow from the ethmoidal,

ciliary, lacrimal, and superior vortex tributaries.

The vein passes through the superior orbital fissure and drains

into the cavernous sinus.

SUPERIOR OPHTHALMIC VEIN:

INFERIOR OPTHALMIC VEIN:

•The inferior ophthalmic vein is supplied by a diffuse plexus of

veins in the floor of the orbit.

•The inferior ophthalmic vein empties into the superior

ophthalmic vein within the orbit and has a small branch, which

drains into the pterygoid venous plexus.119

The dual arterial supply and valveless venous system

provide the orbit with a rich vascular supply.

In obstruction of the internal carotid system, collateral

flow from the external carotid system can provide adequate

flow to the orbit.

The veins allow flow to reverse in case of obstruction.

BIT OF FACT:

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The anastomosing network of vessels can contribute to

clinical problems.

A carotid cavernous sinus fistula can develop secondary to

head trauma or iatrogenic injury, or it can occur

spontaneously.

The anatomic abnormality consists of a communication

between the internal carotid artery and the venous plexus of

the cavernous sinus.

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In cases of severe orbital infection, the valveless venous

system allows spread of infected emboli to the cavernous

sinus and can cause cavernous sinus thrombosis.

The diagnosis is confirmed by visualizing the fistula with

angiography.

Carotid cavernous sinus fistula presents with pulsatile

exophthalmos, bruit, chemosis, engorgement of epibulbar

veins, increased intraocular pressure, ocular ischemia, and

visual loss.

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LACRIMAL SYSTEM

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Lacrimal gland

The lacrimal system produces, distributes, and drains tears.

Tears are produced by the lacrimal gland and multiple accessory

glands.

The lacrimal gland is divided into the orbital lobe and the

palpebral lobe by the lateral horn of the levator aponeurosis.

The lacrimal gland is oriented in the superior-temporal region of

the orbit and lies in the fossa glandular lacrimalis.

The palpebral lobe can be seen by everting the upper lid where it

extends to within a few millimeters of the tarsus.

The ducts of the orbital lobe traverse the palpebral lobe before

opening into the fornix

The gland can be recognized by its pink-gray color and

glandular surface.

Although the gland appears to have a capsule, this is really a

combination of surrounding connective tissue insertions.

The lacrimal nerve, a branch of the ophthalmic division of

Cranial nerve V, provides sensory innervations to the lacrimal

gland.

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Tear drainage

Tears are drained via a conduit of tubes along the medial angle of the

eye.

The system is composed of paired lacrimal papillae, puncta, and

canaliculi that connect to form the common canaliculus, lacrimal sac,

and nasolacrimal duct.

The common canaliculus inserts into the lacrimal sac at an angle to

produce the valve of Rosenm ü ller. This valve prevents reflux of

tears into the canalicular system.

The tears are stored in the lacrimal sac and then drain through the

nasolacrimal duct that opens into the inferior meatus of the nasal

cavity. The nasolacrimal duct is just anterior and lateral to the

uncinate process and can be injured in endoscopic sinus surgery.

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ORBITAL FAT

127

Contains two compartments:

Central compartment (retrobulbar & intracone)

Peripheral compartment (peribulbar & pericone)

The importance of the orbital fat, is that it contains the

motor & sensory nerves for the eye.

Therefore regional anesthesia can be injected into the fat

and provide the patient with an effective block.

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ORBITAL INJURIES

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DISPLACEMENT OF GLOBE

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PROPTOSIS (EXOPHTHALMOS)

Hematoma and swelling of orbital tissue (commonly resolves spontaneously)

Subperiosteal hematoma, notably orbital roof

Inward displacement of orbital bone fragments (persistent proptosis)

ENOPHTHALMOS

Common late sequela, Initially masked by intraorbitaltissue swelling and hematoma

Expansion of the orbit

Prolapse of soft tissue through a blow out fracture

Necrosis of soft tissue and fibrosis

Sucken upper lid may be present.

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DISPLACEMENT OF GLOBE

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VERTICAL DISPLACEMENT

Commonly seen with orbital fractures.

In acute phase upward displacement due to hematoma

and later phases downward displacement is commonly

seen.

HORIZANTAL DISPLACEMENT

Laterally displaced – medial canthal ligament severed

Similar to squint

In both these cases corneal light reflexes are

symmetrical and double vision is not seen.OR

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SUBCONJUNCTIVAL HEMORRHAGE

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Caused by vascular rupture beneath the bulbar conjunctiva or by osmotic increase of vascular wall

Treatment:

1)find out the cause

2)good explanation

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ORBITAL HEMATOMA

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Poor Vascular perfusion of the optic nerve and retina

Early recognition

“Gray Vision”

Proptosis (Exopthalmos)

Ecchymosis

Subconjunctival hemorrhage

Afferent pupil defect

Hard globe

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NASO LACRIMAL INJURIES

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• Damage to naso lacrimal drainage system results in

EPIPHORA

• Any lacerations of middle third of lower eyelid should

suspect injury to inferior canaliculus.(3/4th of tear

volume evacuated)

• Epiphora following nasal fractures is due to protective

influence of medial canthal ligament.

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• Post operative epiphora

- due to malposition of lower eyelid

- due to malposition of bone fragments while reducing

fracture fragments

• Dacrocystorhinostomy

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EPIPHORA

Is an overflow of tears onto the face. A clinical sign or

condition that constitutes insufficient tear film drainage from the

eyes in that tears will drain down the face rather than through

the nasolacrimal system.

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ORBITAL FRACTURES

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Orbital fractures can be divided into

Anterior section

- sturdy orbital rim

Posterior section

- comparitively thin lateral walls, roof & floor

- these can be blow–in or blow–out

Isolated orbital fractures accounts for 5% of mid facial

fractures.

Most common is the blow – out fracture.

It can occur in the floor, medial and lateral walls.

Commonly floor of the orbit is involved

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MEDIAL WALL FRACTURES

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Second most commonly disrupted orbital wall.

It causes entrapment or damage of medial rectus muscle and

orbital wall.

Diagnosed consistently by limitation in abduction of the

globe and globe retraction.

Forced duction test is mandatory (FDT)

Axial CT scan is done to evaluate size and extent of defect

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MEDIAL WALL FRACTURES

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If amount of orbital tissue loss is minimal, not necesssary

to seal the fracture site

When the defect is larger, reconstruction is done with

alloplastic or allogenic materials and secured.

Killian and lynch incision – curvelinear, made along the

lateral wall of nose , 12 mm medial to medial palpebrea

Bicoronal flap

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BLOW IN FRACTURES

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Less common

Presents with proptosis because of decreased orbital

volume

Restricted ocular motility

Dipolpia

Minimally displaced – no need of treatment

Immediate decompression with reconstruction

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Due to force from the lateral direction with a severe impact.

Here , the initial impact is taken by Zygomatic bone resulting in

depressed fracture. Then entire middle third will then hinge

about the fragile ethmoid bone and the impact will then be

transmitted to the contralateral side resulting in laterally

displaced zygomatic fracture of opposite side.

(Craniofacial dysjunction)

LE FORT III FRACTUREM

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FRACTURE LINE -

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Line commences near the

frontonasal suture, causes

dislocation of the nasal bones

and disruption of cribriform

plate of the ethmoid bone.Then

line crosses both the nasal bones

and frontal process of maxilla,

near the frontonasal and

frontomaxillary sutures and then

traverses the upper limit of the

lacrimal bones .

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Continuing posteriorly, the

line crosses the thin orbital

plate of the ethmoid bone

constituting part of the

medial wall of the orbit. As

optic foramen is surrounded

by a dense ring of bone, the

fracture line gets deflected

downward and laterally to

reach the medial aspect of

the posterior limit of the

inferior orbital fissure.

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From this point , fracture

descends across the upper

posterior aspect of

maxillae in the region of

sphenopalatine fossa and

upper limit of

pterygomaxillary fissures

and fractures the roots of

pterygoid laminae at its

base.

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ASIGN AND SYMPTOMS

Tenderness

Lengthening of face.

Depression of ocular levels (enophthalmos).

Hooding of eyes, and tilting of occlusal plane, an imaginary

curved plane between the edges of the incisors and the tips of

the posterior teeth.

As a result, there is gagging on the side of injury.

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AMANAGEMENT

OPEN REDUCTION AND

FIXATION

Usually performed once life threatening injuries are

stabilized, to allow the patient to survive the general anesthesia

needed for invasive orthopedic restruction.

First a frontal bar is used, which refers to the thickened

frontal bone above the frontonasal sutures and the superior

orbital rim.

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The facial bones are suspended from the bar by open

reduction and internal fixation with titanium plates and screws,

and each fracture is fixed, first at its superior attachment to the

bar, then at the inferior attachment to the displaced bone.

For stability, the zygomaticofrontal suture is usually replaced

first, and the palate and alveolar ridge are usually fixed last.

Finally, after the horizontal and vertical maxillary buttresses

are stabilized, the orbital fractures are fixed last.

INFECTION

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Preseptal Cellulitis

◦ Vision, motility of pupils, disc are

normal

◦ globe itself is not proptotic (forward

displacement )

Orbital Cellulitis

◦ 90% secondary to sinus disease

◦ high risk of morbidity and mortality

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ORBITAL CELLULITIS & ABSCESS

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• Infection of retroseptal soft tissue of the orbit.

• Serious condition that should be quickly diagnosed and

treated.

• Mostly occurs in children and spreads from sinuses.

• Typically begins with painful swelling of the eyelids and

chemosis is seen mostly.

• Distuingished from preseptal cellulitis by presence of

proptosis, limitation of ocular movements, pupillary

dysfunction and optic nerve damage.

• Should be diagnosed radiographically.

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DENTAL SIGNIFICANCE

Both superficial and deep infections of the orbit can occur

from a dental focus of infection.

Odontogenic infections can spread to the orbit via several

routes.

Infection from maxillary premolar and molar tooth may

perforate the maxillary buccal plate and spread posteriorly into

pterygopalatine and infra temporal fossa.

Gaining orbital access through infraorbital fissure or

perforating posterior maxillary wall to enter maxillary sinus.

Infection may be pulpally or periodontally.

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Traumatic injuries leading to orbital fractures and infections

can occur due to number of causes including accident falls, road

traffic accidents, blow during fights, contact sports, etc..

Prevention of these trauma can lead to less orbital injuries.

Wearing a HELMET while riding a two wheeler.

Wearing a SEAT BELT while driving a car.

Most contact sports make players wear a guard or helmet and

it is in most games mandatory.

Accident falls are sometimes unavoidable. We need to watch

our own steps and need to take primary protection (especially

for childrens)

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