Surgical Anatomy For Orbital Procedures .pptx

PREPARED BY:
ANWAR ABDULWALI MAHYOUB
SURGICAL
ANATOMY
FOR ORBITAL
PROCEDURES
SUPERVISED BY:
PROF.AHMED AL-KHATRI

INTRODUCTION
A comprehensive knowledge of the orbit and periorbital area aids in
diagnosis and management of disorders in this region.
The two orbital cavities are situated on either side of the sagittal
plane of the skull between the cranium and the skeleton of the face.

INTRODUCTION
During any orbital surgery, there are several anatomical limits and
considerations that surgeons must keep in mind to ensure the safety and
success of the procedure. Here are some important anatomical limits
during orbital surgery
So we should have complete information about the anatomy of the
orbital region structures.

RELATIONS OF ORBIT
 Superiorly—anterior cranial fossa and frontal sinus
 Laterally—temporal fossa (anteriorly); middle cranial fossa (posteriorly)
 Inferiorly—maxillary sinus
 Medially—ethmoid sinus and anterior part of sphenoid sinus.
 Due to the close proximity of these structures, any infection can spread
across these regions.
 For instance, an infection of the ethmoid sinuses can easily invade the orbit
through the thin lamina papyracea.

 EMBRYOLOGY OF ORBITAL WALLS
 The orbital walls are derived from the cranial neural crest cells which expand to
form the frontonasal process and maxillary process
 Inferior, medial, and lateral walls develop from the lateral nasal process and
maxillary process.
 Orbital roof is formed from capsule of forebrain
 Ossification of the orbital bones can be either enchondral or membranous
 First bone to develop is maxillary bone, around 6 weeks of intrauterine life.
 It develops from elements in the region of the canine tooth.
 Secondary ossification centers are in the orbitonasal and premaxillary regions.

 Other orbital bones develop at around 7 weeks of intrauterine development
 Frontal, zygomatic, maxillary, and palatine bones have intermembranous origin
 Sphenoid bone has both enchondral and membranous origin
a) Lesser wing of sphenoid—develops at 7 weeks of intrauterine development. It has
enchondral origin
b) Greater wing of sphenoid—develops at 10 weeks, has intermembranous origin
c) Both wings join at 16 weeks of age.
 Ossification completes at birth, except the orbital apex
 In the early stages of development, human eyes are directed in opposite direction.
 With facial development, angle between optic stalk decreases and is about 68° in adults.

Clinical significance
Deficits in neural crest cell migration and
differentiation cause CRANIOFACIAL
ABNORMALITIES .
Failure of fusion of neural crest waves results in
clefting syndromes such as
 dermoid cyst ( at the frontozygomatic and
frontoethmoidal suture lines )
Fig.1 dermoid cyst

 SIZE, SHAPE, AND VOLUME OF ORBIT
 Orbit is shaped like a quadrilateral pyramid, with the base
anteriorly and apex directed posteriorly.
 The orbits are aligned such that medial walls are parallel to each
other and lateral walls are perpendicular to each other.
 The angle between the medial and lateral wall is 45°.
 The axis between visual axis and orbital axis is 23°.

 The average dimensions of the
orbit are as follows (A And B):
a) Height of orbital margin—40 mm
b) Width of orbital margin—35 mm
c) Interorbital distance—25 mm
d) Volume of orbit—30 cm3
e) Depth of orbit—40–50 mm Fig.2 A and B: (A) Dimensions of the orbit;
(B) Depth of Safe limit for intraorbital dissection
of orbital walls during surgery.

Fig.2 (A) Dimensions of the orbit; (B) Depth of Safe limit for intraorbital dissection of orbital walls during surgery.

 OSTEOLOGY
 The orbit is composed of seven bones:
1) frontal,
2) lacrimal bone,
3) zygoma,
4) maxilla,
5) ethmoid,
6) sphenoid,
7) and palatine bone.
Fig.3 Seven bones of the orbit.

 OSTEOLOGY
 These seven bones
compine together to form
the orbital walls :
1. Medial
2. Lateral
3. Superior(roof)
4. Inferior(floor)
Fig.4 The orbital walls

 SUPERIOR WALL OR ROOF
 Formed by:
1) Orbital plate of frontal bone
2) Lesser wing of sphenoid
 Concave in shape
 Separates orbit from anterior cranial fossa
Fig.5 SUPERIOR orbital WALL OR ROOF

 SUPERIOR ORBITAL WALL LANDMARKS
1. The medial aspect has fovea for trochlea, 4 mm behind
the orbital margin
2. The lateral most aspect accommodates fossa for
lacrimal gland, behind the zygomatic process of frontal
bone.
3. The superior orbital rim has a notch at the junction of
medial one-third and lateral two-thirds:
The supraorbital notch WHICH
Transmits supraorbital nerve and vessels-supplies
forehead.
Fig.6 SUPERIOR orbital WALL landmarks

Applied Anatomy:
1) Mucocele from the frontal sinus extends to orbital cavity
2) Fracture of superior margin may damage or displace trochlea
and producing symptoms of superior oblique palsy
3) In old age,roof is absorbed at places, so that periorbita and
dura mater come into contact- Increased risk of postoperative
CSF leaks.
4) It can easily nibbed away in transfrontal orbitotomy

 MEDIAL ORBITAL WALL
 Composed of four bones, from
anterior to posterior:
 1. Frontal process of maxilla
 2. Lacrimal bone
 3. Orbital plate of ethmoid
 4. Body of sphenoid.
Fig.7 Bones of Medial orbital WALL

 MEDIAL ORBITAL WALL LANDMARKS
1- Orbital plate of ethmoid is the largest part of
medial orbital wall.
 It is very thin (papyraceous).
 It separates orbit from ethmoid sinuses.
2- The frontoethmoidal suture line marks the
approximate level of ethmoidal sinus roof, hence
any dissection above this line should be avoided
as it will expose the cranial cavity.
Fig.8 Medial orbital WALL landmarks

 3- Lacrimal fossa is a depression in the inferomedial orbital rim
Is located between the anterior and the posterior lacrimal crests
 It is formed by maxillary (anterior part) and the lacrimal bone
(posterior part).
 It is bounded by two projections, i.e. anterior lacrimal crest of
maxillary bone and posterior lacrimal crest of lacrimal bone.
 Lacrimal bone is thin whereas the maxillary bone is quite thick.
 If maxillary bone is predominant in the lacrimal fossa, then
osteotomy becomes quite difficult during dacryocystorhinostomy
(DCR) surgery.
Fig.9 Lacrimal fossa

4- Lamina Papyracea
 ~ Is the thin ethmoidal component of the medial wall.
5- Anterior and Posterior Ethmoidal Foramina
 ~ Are located at the frontoethmoidal suture.
 ~ Serve as landmarks for the level of the cribriform plate.
 ~ Transmit:
a) Anterior ethmoidal artery and nerve
b) Posterior ethmoidal artery and nerve (sphenoethmoidal nerve)

6- Nasolacrimal canal lies in the
inferomedial part of orbit through which
the nasolacrimal duct traverses.
7- The nasolacrimal duct is 3–4 mm in
diameter, it passes backward, downward,
and laterally to open into the inferior
meatus under the inferior turbinate.

8- Sutura longitudinalis imperfecta of Weber
 lies in the frontal process of maxilla just anterior to
the lacrimal fossa.
 This suture runs parallel to the anterior lacrimal crest.
 Small branches of infraorbital artery pass through this
groove to supply the nasal mucosa.
 The presence of these vessels should be anticipated
in any lacrimal sac surgery to avoid intraoperative
bleeding.

 SURGICAL IMPLICATIONS
 The average distance between the anterior
lacrimal crest and the anterior ethmoidal
foramen is 24 mm, between the ethmoidal
foramina is 12 mm, and between the posterior
ethmoidal foramen and the optic canal is 6 mm.
 Keeping in mind the "rule of halves" can help in
remembering these landmarks.
Fig.13 Relations of anterior and posterior ethmoidal foramina.

 Disruption of medial wall leading to
nasoorbitoethmoidal fracture (NOE fracture) or
any lateral displacement of the walls leads to
hypertelorism.
 Any trauma to frontal process of maxilla where
medial canthal ligament is attached, leads to
telecanthus.
Fig. 14 Nasoorbitoethmoid (NOE) Fractures

 LATERAL ORBITAL WALL
 Formed by:
1) Greater wing of sphenoid (posteriorly)
2) Zygoma (anteriorly)
 Thickest bone
 Greater wing of sphenoid separates orbit
from middle cranial fossa.
 Congenital absence of this bone in cases
like neurofibromatosis results in pulsatile
proptosis due to orbital encephalocele
Fig.15 LATERAL ORBITAL WALL

 LATERAL ORBITAL WALL LANDMARKS
1- WHITNALL'S TUBERCLE:
 It is a small bony promontory within the lateral orbital
rim to which several structures attach:
a) Check ligament of the lateral rectus muscle
b) Suspensory ligament of the globe
c) Lateral palpebral ligament
d) Lateral horn of the levator aponeurosis
 It Is located in the anterior part of the wall, 11 mm
below the frontozygomatic suture and 4 mm posterior
to the orbital rim.
Fig.16 LATERAL ORBITAL WALL

SURGICAL IMPLICA TIONS
 The term check ligament is a misnomer because it neither checks the
excursion of the extraocular muscle nor is a ligament.
 It is a fascial extension from the muscle sheath through overlying
Tenon's capsule and inserts on the orbital wall.
 It provides support for the globe and surrounding tissue and only
limits motility when it is scarred.

2- The frontal process of zygomatic bone and zygomatic process of
frontal bone
are thick bones and thus protect globe during injury
 Posterior part of this lateral wall is thin (about 1 mm), composed of
orbital plate of greater wing of sphenoid and posterior zygomatic bone
 The superior orbital fissure (between lateral and superior walls of
orbit) and the inferior orbital fissure (between lateral and inferior walls
of orbit) transmit important structures

3- Zygomaticosphenoid suture
is an important landmark for lateral orbitotomy.
Superiorly the bony incision is usually made just above the frontozygomatic suture.
 The lateral wall removal is completed by fracturing the bone at the
zygomaticosphenoid suture
 The recurrent meningeal branches of the ophthalmic artery (internal carotid
supply) exit the orbit via the frontosphenoid suture to anastomose with the middle
meningeal artery (external carotid supply)
 The zygomaticofacial and zygomaticotemporal neurovascular structures leave the
orbit via their respective foramina.

 Applied Anatomy
In resection of maxilla, the Whitnall’s tubercle is spared, otherwise
Damage to Lockwood’s ligament
Inferior dystopia of eyeball
Diplopia

 ORBITAL FLOOR
 Triangular in shape and shortest of all the walls
 Formed by:
1) Orbital plate of maxilla
2) Zygoma
3) Palatine.
 Separated from lateral wall by inferior orbital
fissure
Fig.17 ORBITAL FLOOR

 ORBITAL FLOOR
ORBITAL FLOOR LANDMARKS
1- Inferior orbital fissure weakens the floor.
 Blow out fractures usually occur medial to it
 Medially, it is bounded by maxilla ethmoidal strut. It
is important to preserve this during orbital
decompression surgery to avoid hypogeous and
postoperative diplopia
 The inferior oblique muscle arises anteromedially,
immediately lateral to the nasolacrimal canal.
Fig.18 ORBITAL FLOOR

 ORBITAL FLOOR
2- Infraorbital groove
becomes a canal anteriorly, through this groove passes
the infraorbital nerve and artery (maxillary division of
trigeminal nerve and the terminal branch of internal
maxillary artery).
 They exit through the infraorbital foramen to supply
the lower eye lid, cheek, upper lip, and upper anterior
gingiva
 The infraorbital foramen is located about 6–10 mm
below the infraorbital rim
Fig.19 ORBITAL FLOOR LANDMARKS

 ORBITAL FLOOR
 Applied Anatomy
 Orbital blow out fracture refers to fracture
of orbital floor
 Fracture usually results when an object
larger than the transverse diameter of orbit
strikes the globe

 ORBITAL FISSURES AND CANAL
 Various
important nerves
and vessels are
transmitted
through fissures
and canals in the
orbit.
Fig.20 Orbital fissures and foramina.

1- SUPERIOR ORBITAL FISSURE
Fig.21 Superior orbital fissure.
 Location—between greater and lesser
wing of sphenoid.
 It lies between roof and lateral walls of
orbit.
 Also known as sphenoidal fissure
 It is 22 mm long, largest communication
between orbit and middle cranial fossa

 It usually narrows laterally and widens medially, below the
optic foramen.
 Its tip is about 30–40 mm from frontozygomatic suture
 Its medial part is separated from the optic foramen by
posterior part of the lesser wing of the sphenoid
 The annulus of Zinn, a tight fibrous ring, divides the
superior orbital fissure into intraconal and extraconal
spaces.
Fig.22 The annulus of Zinn and SOF relationship

 Structures passing through upper part:
1) Lacrimal nerve
2) Frontal nerve
3) Trochlear nerve
4) Superior ophthalmic vein.
Structures passing through lower part,
outside the annulus of Zinn:
1) Inferior ophthalmic vein.

 Structures passing through annulus of Zinn:
1) Superior division of 3rd nerve
2) Nasociliary nerve
3) Sympathetic root of cervical ganglion
4) Inferior division of 3rd nerve
5) 6th nerve
6) Sympathetic fibers.

 Clinical applications
Radiographic enlargement of the superior
orbital fissure may occur in:
- meningioma
- pituitary adenoma or
- tumors of the orbital apex

 Inflammation of the superior orbital
fissure and apex may result in a multitude
of signs including ophthalmoplegia and
venous outflow obstruction
TOLOSA HUNT SYNDROME

 SOF Syndrome/ Rochon-Duvigneaud's
syndrome
 Caused by Fracture through orbital roof
 varying degree of CN III, IV, V-1 and VI palsy
 CN V-2 and CN II spared
 diplopia, paralysis of extra ocular muscle,
proptosis

2- INFERIOR ORBITAL FISSURE
 Location—lies between lateral wall and floor
of the orbit.
 It is about 1 cm posterior to the inferolateral
orbital rim
 It is also known as sphenomaxillary fissure
 It is about 20 mm long
 The orbit communicates with the
pterygopalatine and infratemporal fossa
Fig.23 INFERIOR ORBITAL FISSURE

 STRUCTURE PASSING:
1) Maxillary division of the trigeminal nerve
2) Zygomatic nerve
3) Branches from the sphenopalatine ganglion
4) Branches of the inferior ophthalmic vein leading to the pterygoid plexus
 The maxillary division of trigeminal nerve and the terminal branch of
internal maxillary artery enter the infraorbital groove and canal to become
the infraorbital nerve and artery.

 The inferior orbital fissure varies in distance from the orbital rim but may
approach it quite closely (10 mm) before becoming the infraorbital canal.
 This is important to recognize during surgical dissection along the orbital
floor, for it is possible to confuse tissue passing through the inferior
orbital fissure as "entrapped" orbital soft tissue during repair of a fracture
of the orbital floor

Infraorbital Groove
 .. Runs anteriorly from the
inferior orbital fissure IOF
and becomes a canal.
 .. Forms the infraorbital
foramen on the anterior wall
of the maxilla .
 .. Transmits the infraorbital
artery, vein, and nerve
Fig.23 Anatomic dissection of the orbital floor, lateral and inferior orbital rims.
IOF, inferior orbital fissure after incision of
contents; ION, infraorbital nerve in canal/groove after unroofing; ZFN,
zygomaticofacial nerve; ZTN, zygomaticotemporal nerve.

3- OPTIC FORAMEN
 The foramen is present in the lesser wing of
sphenoid lies medial to the superior orbital
fissure and is separated from it by a bony optic
strut
 Conveys the optic nerve and ophthalmic artery
 The optic foramen is about 6.5 mm in diameter.
Fig.25 The optic foramen and canal

3- OPTIC FORAMEN
 Optic canal attains its adult size by 3 years of age.
 It is supposed to be bilaterally symmetrical.
 Any variation in size between two sides should be
considered pathological
 In adults the optic canal is 8–10 mm long and 5–7 mm wide
 Any trauma to optic canal, can result in injury to optic
nerve.

3- OPTIC FORAMEN
Clinical significance:
Blunt trauma cause OC fracture shearing nerve causing traumatic optic neuropathy.
 1 mm difference of canal diameters is significant.
Enlarged in
a) optic glioma
b) optic nerve sheath meningioma
c) metastasis
d) Neurofibromatosis
Narrowing in fibrous dysplasia

ORBITAL SOFT TISSUES
1) Eyelids
2) Periorbita
3) Extraocular muscles
4) Lacrimal system.

 EYELIDS
 The eyelids act to protect the anterior surface of the globe from
local injury.
 Additionally, the maintenance by distributing the protective and
optically important tear film over the cornea during blinking.
 They aid in tear flow by their pumping action
 They aid in the regulation of light reaching the eye,
 and they aid in the tear film of the conjunctival sac and lacrimal sac.
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 SURFACE ANATOMY OF EYELIDS
 The upper eyelid extends
superiorly to the eyebrow,
separating it from the forehead.
 The lower eyelid extends below
the inferior orbital rim to join
the cheek, creating folds.
Fig.26 Sagittal section through the orbit and globe. C, palpebral conjunctiva; IO, inferior oblique muscle; IR, inferior rectus muscle;
OO, orbicularis oculi muscle; OS, orbital septum; P, periosteum/periorbita; TP, tarsal plate

 The nasojugal fold runs from the
inner canthal region, forming the
tear trough.
 The malar fold runs from the outer
canthus toward the inferior aspect
of the nasojugal fold.
Fig.26 The nasojugal fold

 The opened eye presents the palpebral fissure,
a fusiform space between the lid margins.
 The lateral canthal angle is 2 mm higher in
Europeans than the medial canthal angle in
Asians.
 The palpebral fissure includes
1) the lateral canthus,
2) medial canthus,
3) and lacrimal papillae. Fig.27 The palpebral fissure

 Eyelid Margin
 The eyelid margin contains many important
structures and is ordered in a specific way, as
are all the layers of the eyelid.
 Knowing the orientation and position of the
margin structures is especially important with
trauma, where restoration of the anatomy as best
as possible is critical.
Fig.28 Eyelid margin anatomy.

 Eyelid Margin
From anterior to posterior, the
structures seen are:
1) Skin
2) Eyelashes (cilia)
3) Grayline
4) Meibomian gland orifices
5) Mucocutaneous junction
6) Palpebral conjunctiva
Fig.29 Eyelid margin anatomy.

 Eyelid Margin
SURGICAL IMPLICA TIONS
Chalazion (or meibomian cyst )is the most
frequently encountered swelling of the eyelid and
represents a lipogranulomatous inflammation of the
meibomian gland secondary to obstruction.

 OVERVIEW OF STRUCTURE OF EYELIDS
1) Skin
2) Subcutaneous connective
tissue
3) Orbicularis oculi muscle
4) Orbital septum
5) Levator palpebrae
superioris muscle (not
present in the lower eyelid)
6) Müller muscle (inferior
tarsal muscle in the lower
eyelid)
7) Tarsus
8) Conjunctiva
Fig.30 Correlation of the surface anatomy of
the eye in relation to the bony orbit

 SKIN AND SUBCUTANEOUS TISSUE
 The skin of the eyelids is the thinnest of the body (<1 mm).
 The nasal portion of the eyelid skin has
- finer hairs and more sebaceous glands than the temporal aspect,
making this skin smoother and oilier.
 The transition from this thin eyelid skin to the thicker skin of the eyebrow
(approximately 10 mm below the lower eyebrow hairs) and the cheek skin
(below the nasojugal and malar folds) is clinically evident.
 These boundaries should be considered in reconstructive eyelid surgery.
 The subcutaneous tissue consists of loose connective tissue.

Fatis very sparse in preseptal and preorbital
skin and is absent from pretarsal skin.
 Subcutaneous tissue is absent over the
medial and lateral palpebral ligaments, where the
skin adheres to the underlying fibrous tissue.
 Dermatochalasis, blepharochalasis, and
epicanthic folds
all are conditions that primarily involve the skin and
subcutaneous tissue of the eyelids.
Fig.31 EYELID SKIN AND SUBCUTANEOUS TISSUE

Skin grafts from other parts of the body do not match with the skin
of the eyelid, which is the thinnest of the body.
Suitable donor sites include skin from the upper eyelids, skin
from the preauricular, the postauricular, and the supraclavicular
regions, and skin from the inner aspect of the arm.
 At each of these sites, skin is thin and non-hair-bearing.

Edema readily forms in the loose subcutaneous tissues of the eyelids.
This is evident in some allergic conditions.
 Clinically, it is important to differentiate between
dermatochalasis and blepharochalasis.
Blepharochalasis, a rare disorder usually seen in the young, is produced by
recurrent attacks of eyelid edema.
Dermatochalasis is a stretching of the upper eyelid skin typically secondary to
orbital fat herniation through a stretched septum.

 ORBICULARIS OCULI MUSCLE
 The orbicularis oculi muscle is one of the
superficial muscles of facial expression.
 It is invested by the superficial
musculoaponeurotic system (SMAS), muscle
contracture is translated into movement of
the overlying tissues by the fibrous septa
extending from the SMAS into the dermis.
Fig.31 Anatomic dissection of orbicularis oculi muscle fibers.
Note the extreme thinness in this older specimen.

PARTS
 The muscle may be divided into the:
1) Orbital part
2) Palpebral parts— The latter being
divided further into:
a) Preseptal parts
b) Pretarsal portions Fig.33 ORBICULARIS OCULI MUSCLE PARTS

 The orbital portion extends in a wide circular fashion around the orbit,
interdigitating with other muscles of facial expression.
 It has a curved origin from the medial orbital margin, being attached to the
superomedial orbital margin, maxillary process of the frontal bone, medial
palpebral ligament, frontal process of the maxilla, and inferomedial orbital margin.
superiorly to intermix with the frontalis muscle and corrugator supercilii muscle,
laterally to cover the anterior temporalis fascia, and
inferiorly to cover the origins of the lip elevators.

 PRETARSAL SEGMENT OF THE ORBICULARIS
OCULI MUSCLE
 It is involved in tear drainage (“pretarsal helps with
Tearing”)
 The portion that attaches to the anterior and posterior
lacrimal crest is called the Tensor Tarsi or
Horner's Muscle
 The upper and lower eyelid segments fuse laterally to
form the lateral canthal tendon.
Fig.34 ORBICULARIS OCULI MUSCLE PARTS

 PRESEPTAL SEGMENT OF THE ORBICULARIS OCULI MUSCLE
 The preseptal muscles form the lateral palpebral ligament (raphe), which
inserts into Whitnall’s tubercle.
 The muscle of Riolan
 It represents the most superficial portion of the orbicularis muscle.
 It corresponds to the gray line of the eyelid margin, and may contribute to
meibomian gland secretion, eyelash position, and blinking.
 It arises from the palpebral segment of the orbicularis muscle.

 The preseptal orbicularis muscles
overlie the orbital septum and take origin
medially from a superficial and deep head
associated with the medial palpebral
ligament.
 The fibers from the upper and lower lid
join laterally to form the lateral palpebral
raphe, which is attached to the overlying
skin. Fig.35 Orbicularis oculi muscle relations

 The pretarsal portion lies anterior to
the tarsus, with a superficial and deep
head of origin intimately associated
with the medial palpebral ligament.
 Fibers run horizontally and laterally to
run deep to the lateral palpebral raphe
to insert in the lateral orbital tubercle
through the intermediary of the lateral
canthal tendon(LCT). Fig.36 Details of medial canthal insertion of orbicularis oculi

FUNCTIONS
1) The palpebral portion is used in blinking and voluntary winking.
2) The orbital portion is used in forced closure.
INNERVATION
 Facial nerve innervation is from the temporal branches and from the
zygomatic branches of the facial nerve.
 The nerves are orientated horizontally and innervate the muscle from
the undersurface.

 SUBMUSCULAR AREOLAR TISSUE
 It is loose connective tissue below the
orbicularis oculi muscle.
 The lid can be divided into anterior and
posterior portions via this potential
plane.
 In the upper lid, it's traversed by levator
aponeurosis fibers, some of which form
the lid crease. Fig.37 retro-orbicularis oculi fat (ROOF)

 SUBMUSCULAR AREOLAR TISSUE
 In the lower eyelid, it's traversed by
orbitomalar ligament fibers.
 The superior continuation leads to
the retro-orbicularis oculi fat
(ROOF) and suborbicularis
oculi fat (SOOF) in the lower
lid.
Fig.38 suborbicularis oculi fat (SOOF)

 TARSAL PLATES
 The tarsal plates are composed of dense fibrous tissue
and are responsible for the structural integrity of the lids.
 Each tarsus is approximately 29 mm long and 1 mm thick.
 The crescentic superior tarsus is 10 mm in vertical
height centrally, narrowing medially and laterally.
 The lower border of the superior tarsus forms the posterior lid
margin.
 The rectangular inferior tarsus is 3.5-5 mm high at the
eyelid center. The posterior surfaces of the tarsi adhere to
conjunctivae. Fig.39 TARSAL PLATES

 TARSAL PLATES
Fig.39 TARSAL PLATES
A: Anterior surface of tarsal plates and canthal
tendons (left eye).
Note the difference in size between the upper and
lower tarsal plates.
B : Posterior surface of the tarsal plates and canthal
tendons (left eye).
Note the vertically arranged Meibomian glands,
visible through the thin conjunctiva

 TARSAL PLATES
 Each tarsus encloses about 25 sebaceous
meibomian glands that span the vertical height
of the tarsus.
 Their ducts open at the lid margin posterior to
the gray line and just anterior to the
mucocutaneous junction.
 The medial and lateral ends of the tarsi are
attached to the orbital rims by the medial and
lateral palpebral ligaments.
Fig.40 Meibomian glands

 MEDIAL PALPEBRAL
LIGAMENT
 The medial palpebral ligament (medial canthal tendon
[MCT]) is a fibrous band stabilizing the medial tarsi and
is intricately related with the orbicularis oculi muscle
and the lacrimal system.
 The superficial head of the pretarsal orbicularis
muscle lies anterior to the canaliculi and forms the
anterior limb of the MCT.
 This head is primarily horizontal but also has a
superior supporting extension inserted onto the frontal
bone.
Fig.41 Medial palpebral ligament

 MEDIAL PALPEBRAL LIGAMENT
 The deep head of the pretarsal orbicularis muscle (also constituting the
Horner's muscle) inserts into
1) the posterior lacrimal crest
2) and onto the fascia of the lacrimal sac.
 The upper and lower lid preseptal orbicularis have a superficial head that inserts
into and augments the MCT and deep heads that insert into the lacrimal sac fascia.
 The lacrimal sac, encased in fascia, is related anteriorly, laterally, and
posteriorly to constituents of the MCT and medially to the bony fossa of the
lacrimal sac.

 MEDIAL PALPEBRAL LIGAMENT
 The medial palpebral ligament serves as a landmark for locating the lacrimal sac.
 By displacing the eyelid laterally, the tensed lower border of the ligament
can easily be palpated.
 The ligament is often detached from its periosteal attachment to the anterior
lacrimal crest for surgical exposure of the lacrimal sac
 Injury to the medial canthal tendon, as in avulsion, may involve the lacrimal
canaliculi

 LATERAL PALPEBRAL LIGAMENT
 The lateral palpebral ligament (lateral
canthal tendon [LCT]) is formed by
dense fibrous tissue arising from the
tarsi and passes laterally deep to the
septum orbitale to insert into the
lateral orbital tubercle 1.5 mm
posterior to the lateral orbital rim.
Fig.42 Lateral palpebral ligament

 LATERAL PALPEBRAL LIGAMENT
 The tendon is approximately 10.5 mm in length and 6.5 mm in width, and
the midpoint of the LCT inserts 10 mm inferior to the frontozygomatic
suture.
 A small pocket of fat (Eisler pocket) lies between the septum and the
LCT.
 The LCT is also attached to the lateral orbital rim more superficially,
through the orbital septum.
 Superiorly, the LCT is contiguous with the lateral horn of the levator
aponeurosis, while the inferior edge is well-defined and arcs inferiorly to its
insertion.

 ORBITAL SEPTUM
 The orbital septum is a
connective tissue structure
that attaches peripherally
at the periosteum of the
orbital margin
Fig.43 Anatomic dissection of orbital septum in the lower eyelid

 ORBITAL SEPTUM
 It is anterior soft tissue boundary.
 It is extension of periorbita
 It originates from arcus marginalis.
 It extends from tarsus to the orbital rim
 It acts as a physical barrier, separates the
orbital contents from eyelids
 It is covered anteriorly by preseptal
orbicularis muscle and skin. Fig. 44 Extension of orbital septum.

 ORBITAL SEPTUM
 The orbital septum prevents infection from passing from the skin to
the orbit, and vice versa.
 Any infection posterior to the septum is called
ORBITAL CELLULITIS.
 PRESEPTAL CELLULITIS- Inflammation of structure anterior to the
orbital septum that is largely the lids.

 ORBITAL SEPTUM
 The orbital septum must be open to approach the
orbital fat.
 Its insertion to the levator aponeurosis varies.
 In Asians, it inserts around 3 mm from the base of the eyelid
margin, while in Westerners the insertion is higher (10
mm), thus accounting for the more defined eyelid crease.
 There has been some controversy concerning the number of
fat pockets in the eyelids.
Fig.45 ORBITAL SEPTUM variations

 LOWER LID RETRACTORS
 The lower eyelid retractor is a fascial
extension from the terminal muscle fibers and
tendon of the inferior rectus muscle,
originating as the capsulopalpebral head.
 As it passes anteriorly from its origin, it splits
to envelop the inferior oblique muscle and
reunites as the inferior transverse ligament
(Lockwood's ligament).
Fig.46 Major retractors of the upper and lower lid

Capsulopalpebral Fascia
• lower lid analog to levator aponeurosis
• originates from attachments to Inferior
rectus
• inserts onto the lower tarsal border
 inferior tarsal m. is
analog to Muller’s, runs post
to Capsulopalpebral Fascia

 The orbital septum fuses with the capsulopalpebral fascia approximately
5 mm below the inferior tarsal border.
 The inferior tarsal muscle (Müller's muscle) lies just posterior to the
fascia and is intimate with its structure.
 In the Asian lower lid, the line of fusion of the orbital septum to the
capsulopalpebral fascia is often higher, or indistinct, with anterior and
superior orbital fat projection, and overriding of the preseptal orbicularis
oculi over the pretarsal orbicularis.

 ORBITAL FAT
 Acts as a cushion to orbital structures
 In the upper eyelid it lies anterior to the levator complex
and posterior to the orbital septum
 It is divided into compartments by connective tissue
septa
 Infratrochlear nerve and medial palpebral artery
branch of the ophthalmic artery course through the
medial fat pad
 In the lower eyelid, the medial fat pad is separated from
the central pad of fat by the inferior oblique muscle. Fig.47 ORBITAL FAT

 ORBITAL FAT
Upper eyelid preaponeurotic fat is found
immediately posterior to the orbital septum and
anterior to the levator aponeurosis.
The medial fat pad usually is pale yellow or white
and lies anterior to the levator aponeurosis
extending superomedial to the medial horn of the
levator.
The central fat pad is yellow and broad.
A portion of the lateral end of this pad surrounds
the medial aspect of the lacrimal gland. Fig.48 Orbital septum with preaponeurotic fat pads

 ORBITAL FAT
 Surgical Significance:
 Traction on fat pad during surgery may cause
deep orbital hemorrhage & compartment
syndrome
 Herniation of the orbital fat in eyelids
(Steatoblepharon) can occur due to
weakening of orbital septum because of aging. Fig.49 Steatoblepharon with
appearance of "bags under eyes.

 CONJUNCTIVA
 The conjunctiva is a transparent vascularized membrane
that
covers the eyelids (palpebral conjunctiva)
and globe (bulbar conjunctiva).
 It is composed of nonkeratinizing squamous epithelium.
 It contains goblet cells, which secrete mucin (forming the
mucin layer of the tear film).
 It contains accessory lacrimal glands of Wolfring
and Krause, which secrete the basal aqueous layer of the
tear film.
Fig.50 conjunctiva

 CONJUNCTIVA
 Palpebral conjunctiva lines the posterior surface of
the lids as tarsal conjunctiva (from the mucocutaneous
junction of the lid margin to the tarsal plate border) and
continues as orbital palpebral conjunctiva into the fornix.
The tarsal conjunctiva is adherent to the tarsus,
while a submucosal lamina propria underlies the orbital
palpebral conjunctiva and allows dissection from the
vascular Müller's muscle.
 At the depths of the fornices, conjunctiva reflects
anteriorly onto the globe as bulbar conjunctiva.
Fig.51 Bulbar conjunctiva

 THE FORNIX CONJUNCTIVA
 It is loose soft tissue lying at the junction
between the palpebral conjunctiva
(covering the inner surface of the eyelid)
and the bulbar conjunctiva (covering the
globe).
 Each eye has two fornices, the superior
and inferior fornices.
 The fornix permits freedom of movement of
the eyelids.
Fig.52 Superior conjunctival fornix

 THE FORNIX CONJUNCTIVA
SURGICAL IMPLICA TlONS
Because the lacrimal ducts open into
the lateral portion of the superior fornix,
surgical manipulations in this area may
cause injury.
Fig.53 Inferior conjunctival fornix

 Conjunctival Annulus (Ring or Limbus)
 It is a line of fusion of the conjunctiva with cornea.
 ~ Is located 1 mm anterior to the true corneal
limbus (junction of the. sclera and the cornea).
 The limbus is produced by attachments of the
bulbar sheath in the sclera.
 The limbus lies 1.5 mm posterior to the corneal
limbus.
 The space between the limbus of the bulbar sheath
and the conjunctiva is used surgically for various
operations for glaucoma Fig.54 glands in conjunctiva

Accessory Eyelid Structures
1- CARUNCLE
The caruncle is modified skin.
Histologically it is covered by
nonkeratinized, stratified squamous
epithelium and contains sebaceous
glands and hair.
Fig.55 CARUNCLE

Accessory Eyelid Structures
2- PLICA SEMILUNARIS
The plica semilunaris is a fold of the
conjunctiva on the medial aspect of the globe.
Histologically, it resembles bulbar
conjunctiva but the stroma contains fat and
some nonstriated muscle.
The epithelium is rich with goblet cells.
Fig.56 PLICA SEMILUNARIS

 PERIORBITA
 It is periosteal lining of the orbital walls
 It is firmly attached at the suture lines, the foramina, the fissures, the arcus
marginalis, and the posterior lacrimal crest
 Posteriorly, the periorbita is continuous with the optic nerve sheath where the
dura is fused to the optic canal
 Periorbita thickens on the orbital surface of the optic canal and the medial aspect
of the superior orbital fissure and gives rise to the tendinous attachments of the
four rectus muscles, the levator superioris, and the superior oblique muscle.
 This tendinous ring is called the annulus of Zinn.

 PERIORBITA
- Provides resistance to spread of infections and tumors
from the sinuses and bones into orbit
- As loosely adherent to bones, pus or blood may easily
collect beneath it.
- During exenteration, it should be carefully lifted at
sites where it is firmly adherent.

 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 peri scleral lymph
space, which is in continuation with subdural and
subarachnoid spaces.
Fig.57 TENON’S CAPSULE

 TENON’S CAPSULE
 Extreme care should be taken during strabismus surgery to
avoid violating the integrity of Tenon's capsule and exposing the
retrobulbar fat, as this would lead to fat adherence syndrome
with restriction of ocular motility

 EXTRAOCULAR MUSCLES
 Each orbit contains six extraocular muscles
that function together to move the eye:
A. Rectus muscles (4)—superior, inferior, lateral,
and medial recti muscle
B. Oblique muscles (2)—superior and inferior
C. Other muscles—the levator palpebrae
D. and Müller's muscle
Fig.58 Origin of extraocular muscles.
(SR: superior rectus; IR: inferior rectus; SO: superior oblique; IO: inferior oblique; LR:
lateral rectus; MR medial rectus; LPS: levator palpebrae superioris)

A- RECTI MUSCLES
 The rectus muscles originate at the
annulus of Zinn,
 The annulus of Zinn is divided into the
superior Lockwood tendon and the
inferior tendon of Zinn.
 The inferior tendon gives origin to parts
of the medial and lateral recti and entire
inferior rectus muscle.
Fig.59 Medial rectus muscle
Fig.60. Lateral rectus muscle

A- RECTI MUSCLES
 The superior tendon gives origin to part of the
medial and lateral recti and all of the superior
rectus muscle.
 The attachments of superior and medial recti
muscles are close to the dural sheath of optic
nerve. Thus causing pain during extreme eye
movements in retrobulbar neuritis.
 The recti are inserted 6–8 mm posterior to the
limbus into the sclera.
Fig.61 Superior rectus muscle
Fig.62 Inferior rectus muscle

A- RECTI MUSCLES
Actions:
1) Medial rectus—Adduction
2) Lateral rectus—Abduction
3) Superior rectus—Elevation,
adduction, intorsion
4) Inferior rectus—Depression,
adduction, extorsion.
Fig.63 Actions RECTI MUSCLES

A- RECTI MUSCLES
 SURGICAL IMPLICA TIONS
 When performing a large recession of the inferior rectus muscle, one
should disinsert the capsulopalpebral head from its attachment to the
inferior rectus because failure to do so will result in lower eyelid
retraction.
 Likewise, failure to disinsert the muscle from the capsulopalpebral head
will result in lower eyelid advancement if a large portion of the muscle is
resected.

B- OBLIQUE MUSCLES
 The superior and inferior oblique muscles
originate separately from the posterior orbital
wall.
1- The inferior oblique muscle
 It arises from the maxilla at the
anteromedial floor of the orbit
 It passes in a posterolateral direction,
immediately inferior to the inferior rectus to
insert into the posterior sclera.
Fig.64 Inferior oblique muscle

B- OBLIQUE MUSCLES
1- The inferior oblique muscle
 SURGICAL IMPLICA TIONS
 Given its anterior location, the inferior oblique muscle may be injured
in superficial penetrating trauma, lacrimal surgery, or lower lid
blepharoplasry.

B- OBLIQUE MUSCLES
2- The superior oblique muscle
 It arises from the sphenoid bone superomedial
to the optic canal.
 It courses in the forward direction lying above the
medial rectus, and through a cartilaginous pulley
(the trochlea) attached to the frontal bone.
 Thereafter, the tendon passes posterolaterally,
running inferior to the tendon of the superior rectus
to insert into the posterior sclera.
Fig.65 Superior oblique muscle

B- OBLIQUE MUSCLES
 Actions:
1) Inferior oblique—extorsion, elevation, abduction
2) Superior oblique—intorsion, depression, abduction.
 Nerve supply of extraocular muscles
 The superior oblique muscle is supplied by the
trochlear nerve.
 The lateral rectus by the abducent nerve,
 All the other extraocular muscles are supplied by the
oculomotor nerve.
Fig.66 Actions RECTI and oblique
MUSCLES

 LEVATOR PALPEBRA SUPERIORIS
ORIGIN
 The levator palpebra superioris (LPS)
arises at the orbital apex from the
undersurface of the lesser wing of the
sphenoid bone.
 The levator muscle and superior
rectus muscle share a developmental
origin and are connected by fibrous
attachments. Fig.67 Levator palpebrae superioris muscle

COURSE
 The LPS proceeds anteriorly for 40 mm
and ends in aponeurosis approximately
10 mm behind the orbital septum.
 The levator complex changes direction
from a horizontal to a more vertical
direction at the superior transverse
ligament (Whitnall's ligament).
Fig.67 Levator palpebrae superioris muscle

 INSERTION
 The medial horn attaches to the posterior lacrimal crest.
 The lateral horn divides the lacrimal gland into orbital and palpebral lobes
before attaching to the lateral retinaculum at the lateral orbital tubercle.
 The aponeurosis fuses with the orbital septum before reaching the level of the
superior tarsal plate border.
 An anterior extension from this fusion inserts into the pretarsal orbicularis oculi
muscle and overlying skin, forming the upper lid skin crease

 INNERVATION
 The levator palpebra superioris is innervated by the superior branch of
the oculomotor nerve, entering the muscle from its inferior surface in
its posterior third.
 FUNCTION
 Elevation of the lid.

 Surgical identification of the levator muscle of the upper eyelid and its
aponeurosis is facilitated by a stepwise dissection.
 The orbital septum is first incised completely.
 The preaponeurotic fat is then retracted or excised.
 The levator aponeurosis is then seen as a white glistening structure
under the septum.

 MÜLLER'S MUSCLE
 Müller's muscle is smooth muscle
innervated by the sympathetic nervous
system.
 ORIGIN
 Fibers originate from the undersurface of
the levator in the region of the aponeurotic
muscle junction and travel inferiorly
between the levator aponeurosis and
conjunctiva.

 MÜLLER'S MUSCLE
INSERTION
 Insert into the superior margin of the tarsus.
ACTION
 The action is to widen the palpebral fissure with increased sympathetic tone.
 About 2 mm of ptosis is observed in Horner's syndrome.

MÜLLER'S MUSCLE
 Loss of orbital sympathetic function will produce the characteristic features
of Horner's syndrome, mild ptosis, miosis, and anhidrosis.
 In Graves' disease, one cause of eyelid retraction is sympathetic muscle
contraction due to adrenergic stimulation and later fibrosis of the superior
tarsal (Miiller's) muscles.

 SURGICAL SPACES OF ORBIT
1) Subperiosteal space
2) Peripheral orbital space
3) Muscular cone.
4) Sub Tenon’s space
Fig.68 Surgical spaces of orbit

 1- SUBPERISOTEAL SPACE
 It lies between orbital bones and
periorbita
 It is limited anteriorly by
strong adhesions between
periorbita and orbital margins.
https://www.imaios.com/en/e-anatomy/head-and-neck/eye Fig.69 Subperiosteal space

 2- EXTRACONAL (Peripheral) SPACE
 It is bounded peripherally by periorbita
 centrally by four recti muscles and their intermuscular septa,
 anteriorly by orbital septum
 posteriorly by:
1) Peripheral orbital fat
2) Muscles—superior and inferior oblique, LPS
3) Nerves—lacrimal, frontal, trochlear, anterior and posterior ethmoidal
4) Vessels—superior and inferior ophthalmic veins
5) Lacrimal gland
6) Lacrimal sac.
Fig.70 Peripheral orbital space

 3- INTRACONAL (Muscular)SPACE
 Bounded anteriorly by Tenon's capsule, peripherally
by four recti and intermuscular septa, and posteriorly
continuous with peripheral space
Contents:
1. Central orbital fat
2. Nerves—optic nerve, oculomotor, abducens,
nasociliary, ciliary ganglion
3. Vessels—ophthalmic artery, superior ophthalmic vein.
Fig.71 Muscular cone.

 4- SUB-TENON'S SPACE
 It lies between the sclera and Tenon's capsule.
 Clinical significance
TENONITIS Tenon's capsule may be affected by
a disease called idiopathic orbital inflammation,
Local anesthesia: may be instilled into space
between Tenon's capsule and sclera to provide
anesthesia for eye surgery, principally cataract
surgery
Fig.72 SUB-TENON'S SPACE

 LACRIMAL APPARATUS
Lacrimal apparatus comprises of:
1) lacrimal gland
2) and its excretory passage.
3) Accessory lacrimal glands
Fig.73 Lacrimal apparatus

 1- LACRIMAL GLAND
 The lacrimal gland lies in the superotemporal orbit, in the
lacrimal fossa of the frontal bone.
 It measures about 20 mm by 12 mm.
 It is divided into larger orbital and smaller palpebral parts
by levator aponeurosis.
 The gland is composed of numerous secretory units
known as acini which progressively drain into small and
larger ducts.

 About 2–6 ducts from the orbital lobe pass through the palpebral
lobe joining with the ducts from the palpebral lobe to form 6–12
tubules to empty into the superolateral conjunctiva.
 Hence, damage to the palpebral lobe may block drainage from the
entire gland.
 About 20–40 accessory lacrimal glands of Krause are located in
the superior conjunctival fornix, about half this number is located
over the lower fornix.

 NERVE SUPPLY
 Nerve supply is innervated by branches from 5th and 7th cranial nerves,
 Sympathetic supply to the lacrimal gland is via the nerves from the superior cervical
ganglion.
 The parasympathetic fibers are supplied via the 6th nerve. Sensory supply is via the
branches of the trigeminal nerve.
 VESSELS
1) Arterial supply—lacrimal artery branch of the ophthalmic artery
2) Venous drainage—ophthalmic veins
3) Lymphatic drainage—preauricular lymph nodes.

1. Care must be taken when a levator resection is being performed to
avoid injury to the ducts of the lacrimal gland near the lateral horn.
2. Excision of the palpebral portion of the lacrimal gland may interfere
with the excretory function of the whole gland because all of the
ductules of the orbital lobe pass through the palpebral lobe

 2- LACRIMAL EXCRETORY SYSTEM
Fig.74 Lacrimal excretory system.
 The lacrimal excretory system begins with
punctum, about 0.3 mm in size.
 It lies at the medial end of each eyelids, at
the junction of ciliated and non-ciliated part.
 The punctal opening widens into the ampulla
and makes a sharp turn to drain into the
canaliculi.

There is a valve at the junction of the common canaliculus and
lacrimal sac known as the Rosenmuller valve.
The lacrimal sac resides in the lacrimal fossa.
It measures about 12–15 mm vertically and 4–8 mm anteroposteriorly.
It opens into the nasolacrimal duct, which is about 15 mm in length.
It has interosseous and meatal parts.
It is directed downward, backward, and laterally and opens in the
inferior meatus.

Valve of Hasner is found at the lower end of the nasolacrimal duct at
the level of the inferior meatus of the nose.
Imperforate Hasner's valve in newborn infants results in congenital
nasolacrimal obstruction.

SURGICAL IMPLICATIONS
The medial wall of the lacrimal sac is adjacent to the most anterior portion
of the middle meatus of the nose and the portion of the nasal cavity (a
portion of the atrium) just anterior and below the middle concha.
This anatomic relationship is important for the intranasal approach to the
lacrimal sac.
Cannulation of the sac with a fiberoptic probe to allow transillumination
through the nose facilitates the location of the sac

DACRYOCYSTITIS is usually secondary to obstruction at the level
of the nasolacrimal duct,
WHILE EPIPHORA may be due to obstruction at any level in the
lacrimal excretory system.

 3-Accessory lacrimal glands
 Krause's glands and Wolfring's glands (or
Ciaccio's glands) are the accessory lacrimal
glands of the lacrimal system of human eye.
 These glands are structurally and histologically
similar to the main lacrimal gland.
 Glands of Krause are located in the stroma of the
conjunctival fornix.
 The glands of Wolfring are located along the
orbital border of the tarsal plate.
 These glands are oval and display numerous acini.
Fig.75 Accessory lacrimal glands

 3-Accessory lacrimal glands
 Previously it was thought that the main lacrimal gland is
responsible for reflex tear secretion and the accessory
lacrimal glands are responsible for the basal secretion.
 But recent evidence suggests that all tearing may be reflex.
 The accessory glands account for approximately 10% of
the total lacrimal secretory mass

ORBITAL NERVES
1. Optic nerve
2. Oculomotor nerve
3. Superior branch of oculomotor
nerve
4. Inferior branch of oculomotor nerve
5. Branch of oculomotor nerve to
ciliary ganglion
6. Trochlear nerve
7. Abducens nerve
8. Trigeminal nerve
9. Ophthalmic nerve
10. Frontal nerve
11. Supraorbital nerve
12. Supratrochlear nerve
13. Nasociliary nerve
14. Posterior ethmoidal nerve
15. Anterior ethmoidal nerve
16. Infratrochlear nerve
17. Long ciliary nerves
18. Branch of nasociliary nerve to
ciliary ganglion
19. Ciliary ganglion
20. Short ciliary nerves
21. Lacrimal nerve
22. Communicating branch of
zygomatic nerve to lacrimal nerve
23. Maxillary nerve
24. Zygomatic nerve
25. Infraorbital nerve

 ORBITAL NERVES
Orbit contains seven nerves.
It comprises of:
1) Optic nerve
2) Motor nerves—Oculomotor, trochlear, and abducens nerves
3) Sensory nerve—Ophthalmic division of trigeminal nerve (V1) and
some contribution from maxillary division (V2)
4) Autonomic center—Ciliary ganglion.

1- OPTIC NERVE
 Optic nerve is the second cranial nerve
 It is about 4 cm in length
Parts:
1) Intraocular—1 mm
2) Intraorbital—30 mm
3) Intracanalicular—5 mm
4) Intracranial—10 mm
Fig.76 Optic nerve

1- OPTIC NERVE
 Intraocular: The nerve fibers start from axons of the ganglion cell layer of
the retina, converge on the optic disc, and pierce the layers of the eye.
 It is 1.5 mm in diameter and expands to 3 mm behind the sclera as it
receives myelin sheaths
 Intraorbital: Extends from the back of the eye to optic foramina
 Its course is tortuous
 The entire intraorbital optic nerve is surrounded by meningeal and
arachnoidal sheaths in continuation with the respective intracranial
layers

1- OPTIC NERVE
Nerve passes through the optic canal to enter the middle
cranial fossa.
 Intracanalicular:
 Ophthalmic artery crosses inferiorly from medial to lateral side
 Sphenoid and posterior ethmoidal sinuses lie medially to it, thus
resulting in retrobulbar neuritis following infection.
 Intracranial Lies above cavernous sinus and combines with the
opposite nerve to form optic chiasma.

1- OPTIC NERVE
 The optic nerve lies within the muscular cone
 Relations:
1) Long and short ciliary nerves and arteries surround the optic nerve
before they enter the eyeball
2) Ophthalmic artery, superior ophthalmic vein, and nasociliary nerve
cross the nerve superiorly from the lateral to medial side
3) Between the optic nerve and lateral rectus muscle lies the ciliary ganglion,
nasociliary nerve, divisions of oculomotor nerve, and abducent and
sympathetic nerve.

 MOTOR NERVES
1)Oculomotor nerve (III)
2)Abducens nerve (VI)
3)Trochlear nerve (IV).

1- OCULOMOTOR NERVE
 The oculomotor nerve divides in the cavernous
sinus into superior and inferior divisions that
enter the orbit through the annulus of Zinn.
 Within this ring, the nasociliary nerve lies
between two branches, while the abducens
nerve on the outside
 The two branches enter the muscular cone and
diverge. Fig.77 Oculomotor nerve

1- OCULOMOTOR NERVE
The superior division moves up
on the lateral side of the optic
nerve.
 It supplies the LPS and
superior rectus muscles
Fig.78 Superior branch of oculomotor nerve

1- OCULOMOTOR NERVE
 The inferior division is located inferiorly
and outside the optic nerve and then
splits to supply the medial rectus,
inferior rectus, and inferior oblique
 The branch to the inferior oblique
travels along the lateral border of
inferior rectus and enters the inferior
oblique Fig.79 nferior branch of oculomotor nerve

1- OCULOMOTOR NERVE
From the branch to the inferior
oblique a small branch arises which
goes to the ciliary ganglion to form its
parasympathetic root.
 After synapses the fibers of the third
nerve combine with sympathetic fibers to
constitute a short ciliary nerve which
supplies ciliary muscle and iris sphincter.
Fig.80 Branch of oculomotor nerve to
ciliary ganglion

2- TROCHLEAR NERVE
 The trochlear nerve enters the orbit just
outside the annulus of Zinn, having crossed
superior to the oculomotor nerve in the
lateral wall of the cavernous sinus
 It travels forward in the orbit crossing from
lateral to medial above the origin of LPS to
enter the lateral border of the superior
oblique at the junction of the posterior third
and anterior two-thirds. Fig.81 Trochlear nerve

2- TROCHLEAR NERVE
 Because of its long course, the trochlear nerve is the most
commonly affected of the cranial nerves in meningitis or trauma.
 This results in paralysis of the superior oblique muscle, leading
to ipsilateral hypertropia and possible head tilt to the
contralateral side

3- ABDUCENS NERVE
 The abductor nerve starts in the medial part
of the superior orbital fissure inside the
annulus of Zinn and outside the branches of
the oculomotor nerve
 It travels along the medial surface of lateral
rectus piercing the muscle at the junction of
the posterior third and anterior two-thirds.
Fig.82 Abducens nerve

SENSORY NERVES
 The trigeminal nerve supplies
sensory innervation to the orbit
and surrounding structures.
 It originates at the lateral and
ventral portions of the pons.
Fig.83 Sensory nerve supply of orbit. (ST: supratrochlear nerve; SO: supraorbital nerve; Lac: lacrimal nerve; ZT: zygomaticotemporal nerve; ZF:
zygomaticofacial nerve; IO: infraorbital nerve; NC: nasociliary nerve; AE: anterior ethmoidal nerve; PE: posterior ethmoidal nerve; IT:
infratrochlear nerve)

SENSORY NERVES
 Most of the supply is from ophthalmic division (V1)
of trigeminal nerve with some contribution from
maxillary division (V2)
 The ophthalmic division extends from the
trigeminal ganglion and passes through the
cavernous sinus to the orbit via the superior orbital
fissure.
 Before entering the orbit through the superior
orbital fissure it divides into lacrimal, frontal, and
nasociliary branches Fig.84 Ophthalmic nerve

SENSORY NERVES
 The lacrimal and frontal nerves enter the
fissure outside the annulus of Zinn and travel
forward in the superior orbit
The lacrimal nerve, the smallest
branch of ophthalmic nerve, travels along the
superior border of the lateral rectus and
supplies the postganglionic secretomotor fibers
to the lacrimal gland, and sensory fibers to the
surrounding conjunctiva and upper eyelid. Fig.85 Lacrimal nerve

SENSORY NERVES
 The parasympathetic fibers travel from the lacrimal nucleus in the pons
to the greater superficial petrosal nerve via the nervus intermedius,
a) to the vidian nerve,
b) to the sphenopalatine ganglion,
c) to the zygomatic branch of the maxillary nerve,
d) to the zygomaticotemporal nerve,
e) and to the lacrimal nerve, to innervate the lacrimal gland

SENSORY NERVES
 The frontal nerve, largest division of the
ophthalmic nerve, divides into the
supraorbital and supratrochlear nerves.
 The supraorbital nerve moves anteriorly
above LPS, leaves the orbit through the
supraorbital notch, and supplies the forehead,
scalp, upper eyelid, and frontal sinus.
Fig.86 Frontal nerve

SENSORY NERVES
 The supratrochlear nerve, medial one,
runs anteriorly above the trochlea and supplies the
medial part of the forehead and upper eyelid
Fig.87 Supraorbital nerve
Fig.88 Supratrochlear nerve

SENSORY NERVES
 The nasociliary branch enters the orbit through
the annulus of Zinn.
 It crosses the optic nerve and passes forward between
the superior oblique and medial rectus muscles.
 Its branches into the anterior and posterior
ethmoidal nerves, two or three long posterior
ciliary nerves to the globe, and short ciliary
nerves which pass through the ciliary ganglion, and
do not synapse. Fig.89 Nasociliary nerve

SENSORY NERVES
 The nasociliary branch
 It terminates as the infratrochlear nerve
which supplies the medial canthus and the
tip of the nose.
 The ethmoidal nerves contribute branches
to the nasal cavity and external nose.
Fig.90 Posterior ethmoidal nerve

SENSORY NERVES
The long ciliary nerves
carry sympathetics from the
superior cervical ganglion
responsible for dilatation of
the pupil
Fig.91 Long ciliary nerve

SENSORY NERVES
The maxillary division of the trigeminal
nerve leaves the middle cranial fossa through the
foramen rotundum and enters the pterygopalatine fossa
 Within fossa after giving off sphenopalatine, posterior
superior alveolar, and zygomatic branches, the main
part of the nerve passes through the inferior orbital
fissure to enter the infraorbital sulcus as the
infraorbital nerve. Fig.92 Maxillary nerve

SENSORY NERVES
 The maxillary division of the trigeminal
nerve
 Within the infraorbital canal, the infraorbital
nerve gives off the anterior superior alveolar
branch supplying the upper front teeth
 It exits at the infraorbital foramen and
supplies the lower lid skin, conjunctiva,
cheek, and the upper lip
Fig.93 Infraorbital nerve

SENSORY NERVES
 The zygomatic branch of V2 passes
through the inferior orbital fissure
and divides into zygomaticotemporal
and zygomaticofacial branches that
supply the skin overlying the lateral
orbit and zygoma.
Fig.94 Zygomatic nerve

SENSORY NERVES
The zygomaticotemporal
branch also gives secretomotor
fibers to the lacrimal nerve that
supplies the lacrimal gland.
Fig.95 Communicating branch of
zygomatic nerve to lacrimal nerve

 CILIARY GANGLION
 It is peripheral parasympathetic ganglion
 It is located near the orbital apex
 Lies between the optic nerve and lateral rectus
 Filamentous branches of the ganglion,
 8–10 in number,
 are called the short ciliary nerves
 and they move forward around the optic nerve,
together with ciliary arteries and the long ciliary
nerves. Fig.96 Ciliary ganglion

 CILIARY GANGLION
It has three roots:
1) Motor or parasympathetic root—comes from the inferior
branch of the third cranial nerve (by the inferior oblique
branch). Its fibers mainly innervate the ciliary muscle and, to a
lesser extent, the sphincter of the iris.
2) Sympathetic root—a branch of the carotid plexus that
enters the orbit via the common tendinous ring the annulus of Zinn
3) Sensory root—a long and fine fiber that rejoins the
nasociliary nerve where it enters the orbit.
This supplies the eye and the cornea.
Fig.97 Ciliary ganglion

 VASCULAR SUPPLY OF ORBIT
1- ARTERIAL SUPPLY
1) Internal carotid artery
2) Ophthalmic artery
3) Lacrimal artery
4) Muscular branches of
ophthalmic artery
5) Central retinal artery
6) Posterior ciliary arteries
7) Anterior ciliary arteries
8) Supraorbital artery
9) Posterior ethmoidal
artery
10) Anterior ethmoidal artery
11) Medial palpebral artery
12) Supratrochlear artery
13) Dorsal nasal artery
14) Maxillary artery
15) Infraorbital artery
16) Superior ophthalmic vein
17) Nasofrontal vein
18) Vorticose veins
19) Inferior ophthalmic vein
20) Infraorbital vein
21) Cavernous sinus
22) Pterygoid venous plexus

ARTERIAL SUPPLY
Ophthalmic artery Internal carotid artery
Maxillary artery
Fig.98-A Arterial supply of orbit.

ARTERIAL SUPPLY
Ophthalmic Artery Overview
It is the first main branch of internal carotid artery,
It provides the main arterial supply to the orbit, with some
contributions from maxillary and middle meningeal artery, branches
of external carotid artery
The ophthalmic artery originates from the internal carotid medial to
the anterior clinoid process, as it exits the cavernous sinus.

ARTERIAL SUPPLY
 Ophthalmic Artery Overview
The ophthalmic artery courses on the inferior aspect of the optic nerve and enters
the orbit through the optic canal
At the entrance, it lies lateral to the optic nerve and medial to the ciliary ganglion.
Then accompanied by the nasociliary nerve, it turns medially, crossing the optic
nerve superiorly and below the superior rectus muscle.
It then moves forward between the superior oblique muscle and the medial rectus
muscle.
It terminates by splitting into two different arteries, the supratrochlear artery and
the angular artery

ARTERIAL SUPPLY
 Branches of the
ophthalmic artery
are divided into
three groups—
ocular, orbital,
and extraorbital
 Ocular branches:
a) Central retinal
artery
b) Ciliary arteries
c) Collateral
branches to optic
nerve
 Orbital branches:
a) Lacrimal artery
b) Muscular arteries
c) Periosteal
branches
 Extraorbital
branches:
a) Posterior and
anterior ethmoid
arteries
Supraorbital
artery
b) Medial palpebral
artery Dorsal
nasal artery
c) Supratrochlear
artery. Fig.98-B Arterial supply of orbit.

1- OCULAR BRANCHES
 CENTRAL RETINAL ARTERY
 First and smallest branch of ophthalmic artery
 Course: It runs beneath the optic nerve, then at about 10–15
mm behind the posterior part of eyeball
 It pierces the dural and arachnoid sheath of the optic nerve and
enters the eyeball through lamina cribrosa
 It continues till papilla and then gives the terminal branches
Fig.99 Ocular blood supply.
Fig.100 Central retinal artery

1- OCULAR BRANCHES
CILIARY ARTERIES
Three types—long posterior ciliary artery, short posterior ciliary artery, and anterior
posterior ciliary artery
A-Long posterior ciliary arteries:
Commonly two in number
Arise in the ophthalmic artery at the point at which it crosses over the optic
nerve.
These enter the sclera not far from where the optic nerve entry point
It runs in the epichoroidal space till the ciliary body, where it divides into
upper and lower branches and encircle iris Anastomose with artery ciliary
arteries to form major arterial circle of iris
Fig.101 Posterior ciliary arteries

1- OCULAR BRANCHES
B- Short posterior ciliary arteries:
Seven in number
Moves in forward direction around the optic nerve
and pierce sclera and supply choroid
At equator it anastomoses with long posterior
ciliary artery, anterior ciliary artery, and major
arterial circle of iris.

1- OCULAR BRANCHES
C- Anterior ciliary arteries:
Seven in number
Arise from muscular branches and pass
in front, over the tendons of the rectus
muscles.
Fig.102 Anterior ciliary arteries

1- OCULAR BRANCHES
CILIORETINAL ARTERY
Present in 15–20%
Enters from the lateral aspect of the optic nerve
Supplies retina between disk and macula.

2- ORBITAL BRANCHES
LACRIMAL ARTERY
Arises near the optic canal above and lateral to the optic nerve. It travels
superolaterally above the lateral rectus muscle to supply lacrimal gland
Branches:
1) Lateral palpebral artery supplies upper and lower eyelid and
anastomoses with medial palpebral artery
2) Zygomatic artery which passes through zygomatic facial and zygomatic
temporal foramina
3) Muscular branch to lateral rectus
4) Recurrent meningeal anastomoses with the middle meningeal artery.
Fig.103 LACRIMAL ARTERY

2- ORBITAL BRANCHES
MUSCULAR BRANCHES
 Supply the extraocular muscles
 Accompany oculomotor nerves along
their course.
Fig.104 Muscular branches of ophthalmic artery

3-EXTRAORBITAL BRANCHES
1) SUPRAORBITAL ARTERY
2) SUPRATROCHLEAR ARTERY
3) ETHMOIDAL ARTERIES( ANTERIOR ETHMOIDAL
ARTERY POSTERIOR ETHMOIDAL ARTERY)
4) MEDIAL PALPEBRAL ARTERY
5) LATERAL PALPEBRAL ARTERY
6) DORSAL NASAL ARTERY
7) INFRAORBITAL ARTERY

1) SUPRAORBITAL ARTERY
Runs between levator muscle and
periorbita
Leaves orbit through superior orbital
foramen along with the nerve
It anastomoses with supratrochlear and
superficial temporal arteries
Fig.105 Supraorbital artery

2) SUPRATROCHLEAR ARTERY
It is the terminal branch
Pierces the orbital septum above
the superior oblique pulley.
Fig.106 Supratrochlear artery

3) ETHMOIDAL ARTERIES
ANTERIOR ETHMOIDAL ARTERY
Enters anterior ethmoidal canal
Supplies anterior and middle ethmoidal
cells, frontal sinus, meninges, anterior
nasal mucosa, and skin of the nose.
Fig.107 Anterior ethmoidal artery

3) ETHMOIDAL ARTERIES
POSTERIOR ETHMOIDAL ARTERY
Runs between medial rectus and superior
oblique muscle to enter posterior ethmoidal
canal
It supplies posterior ethmoidal sinuses,
dura of anterior cranial fossa, and upper nasal
mucosa. Fig.108 Posterior ethmoidal artery

4) MEDIAL PALPEBRAL ARTERY
It arises below the superior oblique pulley
Descends behind the lacrimal sac
It pierces the orbital septum and forms
peripheral and marginal arterial arches; runs
between the orbicularis oculi and tarsal plate.
Fig.109 Medial palpebral artery

5) LATERAL PALPEBRAL
ARTERY
Branches from lacrimal artery
Supplies eyelid
Anastomoses with medial palpebral artery.

6) DORSAL NASAL ARTERY
Terminal branch
Pierces the orbital septum and passes above the
medial palpebral ligament and descends to nose
Supplies lacrimal sac and anastomose with facial
artery.
Fig.110 Dorsal nasal artery

7) INFRAORBITAL ARTERY
A terminal branch of the maxillary artery
It courses through the inferior orbital fissure into the
infraorbital sulcus where it gives off branches to the
orbital fat and muscular branches to the inferior rectus
and inferior oblique muscles before entering the
infraorbital canal to exit at the infraorbital foramen
It anastomoses with the angular artery and the inferior
palpebral vessels. Fig.111 Infraorbital artery

VENOUS DRAINAGE
 The venous
drainage of the orbit
is through the valve
less superior and
inferior ophthalmic
veins.
Fig.112 Venous drainage of orbit.
Fig.113 Superior ophthalmic vein

VENOUS DRAINAGE
1) SUPERIOR OPHTHALMIC VEIN
Larger of the two
It is formed superomedially near the trochlea by the union
of the angular, supraorbital, and supratrochlear veins
It communicates with central retinal vein, receive inferior
ophthalmic vein and two vorticose veins from upper part of
eyeball Leaves the orbit through superior orbital fissure
and drains into the cavernous sinus. Fig.114 Cavernous sinus.

VENOUS DRAINAGE
2) INFERIOR OPHTHALMIC VEIN
It is usually formed anteriorly as a plexus within the
inferomedial orbital fat
It also communicates with the pterygoid plexus via the
inferior orbital fissure and facial vein
Receives muscular branches and inferior vorticose veins
It courses posteriorly along the inferior rectus and usually
drains into the superior ophthalmic vein. Fig.115 Inferior ophthalmic vein

VENOUS DRAINAGE
Both the superior and the inferior ophthalmic veins anastomose with
the veins of the face.
Because the ophthalmic and the facial veins do not have valves,
superficial infections of the skin of the face may lead to retrograde
phlebitis and even cavernous sinus thrombosis.
The anastomosis between the ophthalmic and the angular veins in
the medial corner of the eye may be large and is important to surgeons.

VENOUS DRAINAGE
3- Nasofrontal vein
The nasofrontal vein is a vein located in
the orbit of the eye.
It is responsible for draining blood from
the front of the nose and the forehead
region.
This vein plays a crucial role in the
circulation of blood in the orbital region. Fig.116 Nasofrontal vein

VENOUS DRAINAGE
4- Vorticose veins
The vorticose veins, referred to clinically as the vortex
veins, are veins that drain the choroid of the eye.
There are usually 4-5 vorticose veins in each eye, with at
least one vorticose vein per each quadrant of the eye.
Vorticose veins drain into the superior ophthalmic vein,
and inferior ophthalmic vein.
Vorticose veins are an important ophthalmoscopic
landmark.
Fig.117 Vorticose veins

VENOUS DRAINAGE
5- Infraorbital vein
The infraorbital vein is a vein that drains
structures of the floor of the orbit.
It arises on the face and passes backward
through the orbit alongside the infraorbital
artery and nerve, exiting the orbit through the
inferior orbital fissure to drain into the
pterygoid venous plexus
Fig.118 Infraorbital vein

VENOUS DRAINAGE
6- Cavernous sinus
Cavernous sinuses are paired
interconnected venous plexuses situated
in the floor of the middle cranial fossa on
either side of the sella turcica and
sphenoid sinus.
They are lined by dura mater and consist
of multiple venous channels within.
Fig.119 Cavernous sinus

VENOUS DRAINAGE
6- Cavernous sinus
The cavernous sinuses are intimately related to the internal
carotid artery and its associated sympathetic plexus, the
oculomotor nerve, the trochlear nerve, the abducens nerve,
and the ophthalmic nerve.
Cavernous sinuses are connected to the orbit, the
pterygopalatine fossa, the infratemporal fossa, the
nasopharynx, and the posterior cranial fossa by various
foramina, fissures, and canals in the skull base.

 VARIATIONS
AGE RELATED VARIATIONS
Infantile orbits are more divergent (≈115°) than those of adults (≈40-45°)
Orbital axes - Lie in horizontal plane in infants - slope downwards (≈15-
20°) in adults
Orbital fissures are relatively larger in childhood than in adults (owing
to the narrowness of the greater wing of the sphenoid)
Orbital index- higher in children than in adults (transverse diameter
increases relatively more in the later life)

 VARIATIONS
AGE RELATED VARIATIONS
Interorbital distance is smaller in children- may give false impression of squint
Roof much larger than floor in infancy
Optic canal has no length at birth- a foramen - at 1 year of age≈ 4 mm
Periorbita much thicker and stronger at birth than in adults
SENILE CHANGES-
Holes, particularly in the roof due to absorption of the bony wall
Orbital fissures become wider

 VARIATIONS
GENDER RELATED VARIATIONS
MALES
• Glabella & supraciliary ridges are more marked
FEMALES
1) • Larger
2) • More elongated
3) • Rounder
4) • Upper margins sharper
5) • Frontal eminences more marked

 REFERENCES
1. Shaloo Bageja, Anand I, Jadhav S. Surgical Anatomy of Orbit. Jaypeedigital.com. Published 2019. Accessed February 17, 2024.
https://www.jaypeedigital.com/eReader/chapter/9789352709922/ch1#
2. Peter, Cornelius CP. Anatomy of the Orbit: Overall Aspects of the Peri- and Intra Orbital Soft Tissues. Springer eBooks. Published online January 1, 2023:59-119.
doi:https://doi.org/10.1007/978-3-031-40697-3_3
3. Biswas A. Eyelid Anatomy. Jaypeedigital.com. Published 2024. Accessed February 17, 2024. https://www.jaypeedigital.com/eReader/chapter/9788184489637/ch1
4. Bony anatomy of the orbit. Aofoundation.org. Published 2024. Accessed February 17, 2024. https://surgeryreference.aofoundation.org/cmf/further-reading/bony-anatomy-of-the-
orbit
5. Dr. Antoine Micheau, Dr. Denis Hoa. Anatomy of the eye : illustrations. IMAIOS. Published October 3, 2022. Accessed February 17, 2024. https://www.imaios.com/en/e-
anatomy/head-and-neck/eye?mic=eye-illustrations&afi=1&is=12127&il=en&l=en&ul=true
6. Parviz Janfaza M.D. Surgical Anatomy of the Head and Neck. Harvard University Press; 2011. Accessed February 18, 2024.
https://www.perlego.com/book/1147075/surgical-anatomy-of-the-head-and-neck-pdf
7. Eyeball. Kenhub. Published 2024. Accessed February 17, 2024. https://www.kenhub.com/en/study/overview-of-eyeball
8. Muscles of the orbit. Kenhub. Published 2024. Accessed February 17, 2024. https://www.kenhub.com/en/study/muscles-orbit
9. Salgado-López L, Luciano C.P. Campos-Leonel, Pinheiro-Neto CD, María Peris-Celda. Orbital Anatomy: Anatomical Relationships of Surrounding Structures. Journal of
Neurological Surgery. 2020;81(04):333-347. doi:https://doi.org/10.1055/s-0040-1713931
10.Orbicularis Oculi Muscle - (Origin and Insertion) and Function - (updated in 2022). Health Fixit |. Published June 25, 2014. Accessed February 17, 2024.
https://healthfixit.com/orbicularis-oculi-muscle/
11.Ophthalmology Review. Ophthalmology Review. Ophthalmology Review. Published July 11, 2019. Accessed February 17, 2024. https://www.ophthalmologyreview.org/bcsc-
fundamentals/eyelid-anatomy?ssp=1&setlang=en&cc=XL&safesearch=moderate
12.UFO Themes. Strabismus surgery. Ento Key. Published June 4, 2016. Accessed February 17, 2024. https://entokey.com/strabismus-surgery/

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