Inferior surface of lesser wing
Upper lamina - Anterior
surface of superior tarsus &
skin of upper eyelid.
Middle lamina-superior margin
of superior tarsus.
(Superior Tarsus Muscle
Lower lamina- Superior
• N/S - Upper division of
• Thickened band of orbital fascia
which extends from trochlear pulley
to lacrimal gland and its fossa.
• Formed by condensation of superior
sheath of levator muscle joined
medially by sheath of reflected
tendon of superior oblique muscle.
• It forms a true check ligament of
• C/S :- Damage to Trochlea can lead
to partial ptosis due to damage to
• ACTION :- Elevation of upper eye lid
• C/S :- Drooping of upper eyelid.
> Complete ptosis-injury to occulomotor nerve.
> Partial ptosis-disruption of postganglionic sympathetic fibres from
superior cervical sympathetic ganglion. Or due to damage of whitnalls
• 4 rectus muscles - origin is in the common tendous ring
(annulus of Zinn)
– Oval ring of connective tissue
– Continuous with periorbita
– Anterior to optic foramen.
• Muscles traveling from the this tendon ring to the insertions create muscle
• Origin of SUPERIOR AND MEDIAL RECTUS are closely attached to the dural sheath of the optic
nerve, which accounts for the characteristic pain in a case of Retrobulbar neuritis, felt during upward &
inward movements of the globe.
• Thyroid orbitopathy -> Medial & Inf.rectus thicken. especially near the orbital apex -> compression of
the optic nerve as it enters the optic canal adjacent to the body of the sphenoid bone.
• In ophthalmoplegia proptosis occur due to muscle laxity.
Origin :- Superior limb of the tendonous ring, and optic nerve sheath.
Insertion:- Sclera 7.7 mm away from limbus obliquely making an angle of 23 d
with saggital axis.
(Expansion of the SR is attached to the LPS. Thus when the SR makes the eye
look up ,the upper lid is also raised.)
B/S:- Lateral Muscular Art. Branch of cerebral part of IC
N/S:- 3rd CN Nrv.
*Separated from roof by LPS
Origin :- Annulus of Zinn (upper &
Lowe limb of common tendinous
Insertion:- Sclera , 5.5 mm away from
( The horizontal plane of eye bisects
Fascial expansion from muscle sheath
forms the medial check ligament and
attach to medial wall of orbit
B/S:-Medial Muscular Art. Branch of
cerebral part of IC + lacrimal art.
N/S:- 3rd CN Nrv.
Origin :- Annulus of Zinn
Insertion:- Sclera ,6.5 mm away from limbus
B/S:- Medial Muscular Art. Branch of
cerebral part of IC
N/S:- 3rd CN Nrv.
Origin :- Upper and lower limb of
Annulus of Zinn, AND a process of
the greater wing of the sphenoid
Insertion:- Sclera , 6.9 mm
away from limbus.
Fascial expansion from muscle
sheath forms the lateral check
ligament and attach to lateral wall
of orbit at Whitnalls tubercle
B/S:- Muscular Art. Branch of
cerebral part of IC
N/S:- 6th CN Nrv.
Medial rectus inserts closest to the limbus and is therefore susceptible to injury during ant.
Inadvertent removal of the MR is a well known complication of pterygium removal
The Scleral thickness behind the rectus insertion is the thinnest, being only 0.3 mm thick ->
chances of scleral perforation while suturing
Length of EOM
R EOM dat LONG!!!!!
SR IR MR
LR SO IO
60 mm48 mm
42 mm 40 mm 40 mm
PULLEYS OF EOM
• Discrete rings of dense collagen
tisue encircling EOM & are about
2mm length COAXIAL .
• Each EOM consist of 2 layers -
Global layer & orbital layer.
• Fibres of Global layer become
contiguous with tendon to insert
on the globe ; orbital layer
contains remaining half of EOM
fibres which insert on pulley.
Pulley function as the mechanical origins of EOM & play a vital role in ocular
kinematics especially the rotational properties.
• Clinical Significance:-
1. A-V pattern of squint.
2. Brown syndrome -
difficulty in moving eye
up, particularly during
• All achieved eye orientations
can be reached by starting
from one specific "primary"
reference orientation and then
rotating about an axis that lies
within the plane orthogonal to
the primary orientation's gaze
direction (line of sight / visual
• This plane is called Listing's
• According to Listing
cycloversion was 0
• A critical aspect concerning
Listing’s law is the half angle
States that in order to keep
eye position within Listing’s
plane, the angular velocity
axes of eye rotation MUST
TILT out of the Listing’s
plane by half the angle of the
gaze’s deviation from
To implement this concept
implementation came; which
involves pulley mechanism
Anatomical origin :-lesser wing of the sphenoid bone.
Physiological origin is the trochlea, a cartilagenous “U”
on the superior medial wall of the orbit
Longest thinnest EOM, the muscle ends before the
Insertion:- The insertion line is curved with its
concavity facing the trochlea.
Ant. end lies ~13.8 mm behind the limbus .
Post. end lies ~18.8mm behind the limbus.
The tendon insertion fans out below the SR into parts:
Anterior 1/3 responsible for intorsion
Posterior 1/3 responsible for depression
B/S:- Muscular Art. Branch of cerebral part of IC
N/S:- 4th CN Nrv.
• Origin :- Maxillary bone inferior to
the nasolacrimal fossa.
• The ONLY EOM originating in the
• Insertion:- Posterior lateral aspect
of globe mostly inferior, below the
ant.-post. horizontal plane
• Near the insertion, the inf. vortex
vein are in relation to its post.
• B/S:- Muscular Art. Branch
of cerebral part of IC
• N/S:- CNIII inferior division
Factors involved in mechanics of
action of EOM
1.Cross sectional area of the muscle.
(Muscles exert force in proportion to their cross
2.Length of the muscle.
3.Distance between the anatomic and physiologic insertion
is called the arc of contact.
(The power of the muscle is proportionate to its length
and arc of contact)
MUSCLES CAUSING MONOCULAR
• Extra-ocular muscles can have primary, secondary and tertiary
• Primary muscle action is the main and most powerful direction
in which the eye moves when the muscle is contracted.
• Secondary muscle action is the second direction in which the
eye moves when that muscle is contracted, but is not the main
or most important action.
• Tertiary muscle action is the least powerful direction in which
the eye moves as a result of contraction of the muscle.
MR AD-DUCTION __________ ____________
LR AB-DUCTION __________ ____________
SR ELEVATION INTORSION ADDUCTION
IR DEPRESSION EXTORSION ADDUCTION
SO INTORSION DEPRESSION ABDUCTION
IO EXTORSION ELEVATION ABDUCTION
• When the globe is abducted to 23°, the visual and orbital axis
coincide. In this position it acts as a pure elevator.
• If the globe were adducted to 67° the angle between the visual
and orbital axis would be 90° In this position it would act as a
• When the globe is adducted to 51 ͦ, the visual axis coincides
with the line of pull of the muscle, the SO acts as a depressor.
• When the globe is abducted to 39 ͦ, the visual axis and the SO
make an angle of 90 ͦ, the SO causes only intorsion
Laws of ocular motility
• Synergists - Muscles of the same eye that move the
eye in the same direction. Eg: right SR and right IO.
• Antagonists - A pair of muscles in the same eye that
move the eye in opposite directions. Eg: right LR and
• Yoke muscles - Pair of muscles , one in each eye , that
produce conjugate ocular movements. Eg: right LR
and left MR in dextroversion
HERING’S LAW OF EQUAL INNERVATION
States that during any conjugate eye movements, equal and
simultaneous innervation flows to yoke muscles, which is
required for symmetrical binocular.
SHERRINGTON’S LAW OF RECIPROCAL INHIBITION
States that increased innervation to an EOM is accompanied by
reciprocal inhibition of its antagonist.
THANK YOU EVERYONE FOR PATIENTLY LISTENING TO THIS
For feedbacks & brickbats plz mail at
NO MORE SEMI--NAR
KYUNKI ABKI BAR ……..
• Myokemia is an involuntary, spontaneous, localised quivering of a
few muscles, or bundles within a muscle, but which are insufficient
to move a joint.
• Typically involves the lower eyelid or less often the upper eyelid.
• It occurs in normal individuals and typically starts and disappears
• The condition typically resolves itself.
Dayi ankh ka fadakna - shubh hota hai ya ashubh? what medical
reasons are behing this thing?
आंखों का फड़कना भी कर जाता है बड़ा 'संके त‘
!!!!!! Ever faced such question!!!!!
• WHY WE NEED 6 MUSCLES?
• WHAT IS USE OF INTORSION N EXTORSION?
• MODEL EXPLAINNING EVERYTHING
• ORBITALIS N INF TARSAL DIAG
• Why width of recti are important?
• For listing ..bowl with markings.
• Ptosis pic