ORBIT
It is a pyramidal
cavity with its
apex above and
its base behind.

CONTENTS
(1) Eye ball. 
(2) Extraocular 
muscles.
(3) Bulbar fascia.
(4) Nerves. 
(5) Vessels. 
(6) Orbital fat. 

ORBITAL FASCIA
It is the 
periosteum
covering the bones of
the walls of the orbit.
It is continuous 
through the foramina
and fissures with the
periosteum on the
outer surface of the
bones.
ORBITAL FASCIA
In case of : 
Superior orbital 
fissure.
Optic canal. 
Anterior ethmoidal
canal, it is
continuous with
the endosteal
layer of the dura.

ORBITAL FASCIA
The inferior orbital 
fissure is bridged by
the muscle of
Muller (orbitalis)
muscle.
EXTRAOCULAR MUSCLES
A. Levator 
palpebrae
superioris.
B. Four recti 
(superior,
inferior, medial
and lateral).
C. Two oblique
(superior and
inferior).

LEVATOR PALPEBRAE
SUPERIORIS
Origin : 
Undersurface of
the lesser wing
of the sphenoid
above the optic
canal.

LEVATOR PALPEBRAE
SUPERIORIS
The muscle ends
anteriorly in a
wide
aponeurosis.
This aponeurosis
splits into two
lamellae :
Superior and 
Inferior.


LEVATOR PALPEBRAE
SUPERIORIS
Insertion : 
Suprior lamella : 
To the superior tarsal
plate and the skin of
the upper eyelid.
Inferior lamella : 
Contains (Muller’s 
muscle)
It is inserted into the
superior tarsal plate.


LEVATOR PALPEBRAE
SUPERIORIS
Nerve supply : 
Oculomotor 
nerve (superior
division).
Muller’ muscle :
superior cervical
sympathetic
ganglion.

LEVATOR PALPEBRAE
SUPERIORIS
Action : 
Elevation of the
upper eye lid.
Sympathetic 
stimulation
causes further
elevation of the
eye lid.

PTOSIS
It is Dropping of 
the upper eye lid.
It is due to division 
of the oculomotor
nerve or the cervical
sympathetic
ganglion (Horner’s
syndrome).
THE RECTI
Origin : 
From the common 
tendinous ring (it is
thickened
periosteum which
surrounds the optic
canal and bridges over
the medial end of the
superior orbital
fissure).
THE RECTI
The muscles are 
attached to the
ring in positions
implied by their
names.
The lateral rectus
arises by two
heads.

THE RECTI
Insertion : 
The muscles pass
forwards to the
sclera to be
inserted (6mm)
behind the
cornea (in front
the equator of
the eyeball).

THE RECTI
Nerve supply : 
1. Oculomotor 
nerve : to
Superior,
Inferior and
Medial recti.
2. Abducent 
nerve: to Lateral
rectus.
THE RECTI
Action : 
The medial rectus
rotates the
cornea medially.
The lateral rectus
rotates the
cornea laterally.


THE RECTI
Action : 
Superior and 
Inferior recti
elevate and
depress the
cornea respectively
(in the transverse
axis).
THE RECTI
The superior and
inferior recti are
inserted medial
to the vertical
axis of the eye
ball.
So they can 
rotate the cornea
medially.

SUPERIOR OBLIQUE
Origin : 
Body of the sphenoid
above the common
tendinous ring.
It hooks around a 
fibrocartilaginous
pulley (trochlea) on
the superomedial
border of the front of
the orbit.

SUPERIOR OBLIQUE
Insertion : 
Into the sclera 
beneath the
superior rectus and
behind the coronal
equator of the eye
ball.
Nerve supply : 
Trochlear nerve. 
INFERIOR OBLIQUE
Origin : 
Anteromedial floor of
the orbit.
Insertion : 
Posterolateral part of
the sclera behind the
equator.
Nerve supply : 
oculomotor nerve
(inferior division).


ACTION
Superior oblique: 
Rotates the 
cornea
downwards.
Inferior oblique: 
Rotates the 
cornea upwards.
Both muscles 
rotate the cornea
laterally.
ACTION
The line of pull of
both muscles
pass medial to
the vertical axis
and behind the
equator.

FASCIAL SHEATH OF THE
EYEBALL
It separates the 
eye ball from the
orbital fat and
forms a socket for
its free movement.
It surrounds the 
eyeball from the
optic nerve to the
corneoscleral
junction.
FASCIAL SHEATH OF THE
EYEBALL
It is pierced by
the tendons of
the orbital
muscles.
It is reflected 
onto each of
them as a
tubular sheath.

FASCIAL SHEATH OF THE
EYEBALL
Thickening of the fascia is 
attached to the lacrimal and
zygomatic bones.
It forms the medial and 
lateral check ligaments.
Inferiorly, it forms the 
suspensory ligament which
connects the check ligaments.
The eyeball is suspended from
the medial and lateral walls of
the orbit.

LACRIMAL APPARATUS
It is composed of the 
structures producing
lacrimal fluid and controlling
its passage to the nasal
cavity.
They are : 
Lacrimal gland and its 
ducts.
Conjunctival sac. 
Lacrimal sac. 
Naso lacrimal duct. 
LACRIMAL GLAND
It is a serous gland 
almond in shape in the
supero lateral angle of
the orbit behind the
upper lid.
It consists of a large
orbital part and a
small palpebral
part.

LACRIMAL GLAND
The two parts are 
continuous at the
lateral margin of
the aponeurosis of
levator palpebrae
superioris. The
gland has (6- 12)
ducts that open
into the lateral
part of the
superior fornix.
LACRIMAL GLAND
Nerve supply: 
Facial nerve (through 
greater petrosal and
nerve of pterygoid canal )
to the pterygopalatine
ganglion.
The post ganglionic fibers
pass to the gland through
the zygomatic branch of
zygomatico temporal or
through the lacrimal
nerve.

LACRIMAL CANALICULUS
Tears accumulate in the 
lacus lacrimalis before it
enters the lacrimal
punctuae .
LACRIMAL 
CANALICULUS
They are two. Each about
(10) mm long. They pass
from the lacrimal
punctum in each eye lid
to the lacrimal sac.

LACRIMAL SAC
It is a thin fibrous
sac on the medial
side of the orbit in
the lacrimal fossa.
It receives both
canaliculi and
drains to the
nasolacrimal
duct.

NASO LACRIMAL DUCT
It descends in the medial
wall of the orbit.
It opens into the 
inferior meatus of the
nose. Its opening is
guarded by a flap of
mucous membrane which
prevents air passing up
the duct when the nose is
blown.

LACRIMAL APPARATUS
The lacrimal fluid 
constantly washes the
front of the eye ball and
its conjunctival covering .
It is drained by plinking 
when the increased intra
conjunctival pressure
produced by the closed
eye lids forces the fluid
into the lacrimal puncta.
CONCLUSION OF ACTION
(1) R. Superior 
rectus + L. inferior
oblique.
(2) Superior rectus
+ inferior oblique
(both eyes).
(3) R. Inferior 
oblique + L.
Superior rectus.

CONCLUSION OF ACTION
(4) R. Lateral 
rectus + L. Medial
rectus.
(5) Fixed primary
position.
(6) R. Medial 
rectus + L. Lateral
rectus.

CONCLUSION OF ACTION
(7) R. Inferior 
rectus + L.
Superior oblique.
(8) Inferior recti +
Superior oblique of
both eyes.
(9) R. Superior 
oblique + L.
Inferior rectus.
