The document summarizes key anatomical and physiological details of the extraocular muscles and eye movements: 1. It describes the bony orbit anatomy, six extraocular muscles and their actions, innervation and blood supply. The four rectus muscles control horizontal and vertical eye movements, while the two oblique muscles enable torsional movements. 2. The document outlines uniocular and binocular eye movements including versions, vergences, and diagnostic positions of gaze. Hering's and Sherrington's laws govern coordinated eye movements between the eyes. 3. Supranuclear control systems like saccadic, smooth pursuit, vergence and vestibulo-ocular pathways mediate voluntary and reflexive eye movements

1. Dr.k.vanya

2. Bony orbit
 Angle of the medial and lateral walls of the orbit is 45°
so the optical axis forms approimately 23 °with both
medial &lateral walls.
 The medial walls of the 2 orbits are parallel to each
other.

4. Extraocularmusles(EOM):-6
 Four recti:-
 Superior rectus
 Inferior rectus
 Medial rectus
 Lateral rectus

5.  Two oblique muscles:-
 Superior oblique
 Inferior oblique
 In addition levator palpebrae superioris also present
&it inserts into upper eye lid for elevating palpebral
fissure.
 The 4 rectii arises from fibrous ring (annulus of
zinn)around optic foramen.

6.  Vertical recti(sup.&inf. Rectus ) run in line with orbital
axis & are inserted infront of equator.
 They form an angle of 23° with visual axis.

7. Superior rectus
 Arises from upper part of annulus o zinn.
 Below the attachment of levator M.
 Continuous with attachment of med.,&lat. Recti
 Pierces tenon’s capsule &it is inserted into sclera 7.7
mm from superior limbus.
 Length 48 mm;width 9mm.
 N.supply:-sup.divison of oculomotor N.
 B.supply:-lat. Muscular branch of ophthalmic A.

8. Inferior rectus
 Shortest of all recti
 Arises from lower part of optic foramen.
 Attached to sclera at 6.5 mm from inferior limbus
 Lies b/w globe and inf.oblique.
 Also attached to fascial sheath of lower lid.
 Length 40mm;width 9mm
 N.supply:-branch of inf divison of oculomotor N.
 B.supply:-medial muscular branch of ophthalmic A.

9. Medial rectus
 Largest ocular M& stronger than lateral rectus.
 Arise from medial & inferior sides of optic foramen
 Passing along medial wall of orbit ;inserts 5.5mm from
nasal limbus.
 Length 40mm;thicker than other EOM.
 N.supply:-inf.divison of oculomotor N.
 B.supply:-medial muscular branch of ophthalmic A.


10. Lateral rectus
 Arises from annular tendon.
 Pierces tenon’s capsule &inserts in sclera at 6.9 mm
from temporal limbus.
 Length 48mm;2/3 of cross sectional area of MR.
 N.supply:-Abducent N enters lR on its ocular
aspect,just post.to its mid point.

11. Spiral of tillaux
 Imaginary line joining the insertions of the 4 recti and
is an important anatomical landmark when
performing surgery.
 The insertions are located progressively further away
from the limbus in a spiral pattern.
 the medial rectus insertion is closest .
 Superior rectus is farthest.

13.  Obliques are inserted behind equator & form an angle
of 51° with visual axis.

14. Superior oblique
 Longest& thinnest EOM.
 Arises from common origin at the apex of orbit;
superomedial to optic foramen.
 Runs forward to trochlea(cartilaginous ring at
upper&inner angles of orbit)
 After threading through this it becomes tendinous
 It changes its direction completely and runs over the
globe under SR to attach above & lat, to posterior pole.

15.  Ant.fibres of S.O tendon-intorsion
 Post.fibres of S.O tendon-extorsion
 N.supply:-Trochlear N(4) after dividing into 2-3
branches enters muscle superiorly.
 B.supply:-superior muscular branch of ophthalmic A.

16. Inferior oblique
 Only EOM not arising from apex of orbit
 It arises anteriorly from lower & inner orbital walls
near lacrimal fossa.
 Running below inf.rectus& attaches below&lat. to
post.pole of globe.
 N.supply:-Inf.divison of oculomotor N.
 B.supply:-Infraorbital &medial muscular branches of
ophtalmic A.

17. Action of extraocular muscles
 Rotation around centre of rotation
 Centre of rotation lies 12/13 mm behind cornea.
 3 types of rotation:
1. Rotation around fick vertical axis Z—side to side
2. “ “ fick horizontal axis X– up&down
3. “ “ fick antero posterior axis– torsion

19. Uniocular movements
 Ductions – only one eye is open,the other covered/closed
tested by asking the pt. to follow a target in each direction
of gaze.
 Types of ductions:-
1. Adduction
2. Abduction
3. Supraduction
4. Infraduction
5. Incycloduction
6. excycloduction

21. Binocular movements
 Versions:-both eyes open,attempting to fixate a target
&moving in same direction.
 Binocular ,simultaneous,conjugate movements in
same direction.
 Abduction of one eye accompanied by adduction of
other eye is called conjugate movements.

22. Types of versions:-
 Dextroversion&laevo version
 Elevation&depression
 Dextro elevation&dextro depression
 Laevo elevation& laevo depression

23.  Torsional movements/righting reflexes:-
 When you tilt head to maintain upright image.
 Vergences:-
binocular,simultaneous,disjugate/disjunctive
movements (opp.direction)
 Convergence– simultaneous adduction
 Divergence– outward movement from convergent
position

24. Types of convergence
 Reflex ----tonic
 ----proximal
 ----fusional
 ----accommodative
 voluntary

25. Actions of EOM
ACTION PRIMARY SECONDARY TERTIARY
MR ADDUCTION ------ ---------
LR ABDUCTION ------ ---------
SR ELEVATION INTORSION ADDUCTION
IR DEPRESSION EXTORSION ADDUCTION
SO INTORSION DEPRESSION ABDUCTION
IO EXTORSION ELEVATION ABDUCTION

26.  Both obliques have same tertiary action because
inserted behind the center of rotation,
 pull post. pole of globe medially
 when they contract ant.portion of eye so it causes
abduction

27.  Both recti have same tertiary action bcz they inserted
anterior to centre of rotation
 pull ant.portion of globe medially so it causes
adduction

28.  Synergists:-ref.to muscles having same primary action
in same eye.
 Ex:-sup.rectus & inf.oblique----elevators
 inf.rectus&sup.oblique-----depressors
 Antagonists:-having opp.action in same eye
 Ex:-sup.&inf. Recti
 sup.&inf.oblique

29.  Yoke muscle(contralateral synergists):-
 Ref. to pair of muscles (one from each eye) which
contract simultaneously during version movements.
 Ex :-in dextroversion RLR &LMR
 Contralateral antagonist:-pair of muscle (one from
each eye)having an opposite action.
 Ex:-in dextroversion RLR & LLR

30. Diagnostic positions of gaze:-9
1 Primary position of gaze:-assumed by eyes when
fixating a distant object with head erect.
6 cardinal positions :- to test 12 EOM in their main
field of action

31. 1. Dextroversion
2. Laevo version
3. Dextro elevation
4. Leavo elevation
5. Dextro depression
6. Laevo depression
 +2 Elevation
 Depression

33. Laws of ocular motility
1. Hering’s law of equal innervation:- during any
conjugate movement equal & simultaneous
innervation flows to yoke muscles

34. 2. Sherrington law of reciprocal innervation :-
 inc.innervation to an EOM is accompanied by
reciprocal dec. in innervation to its antagonist.
 Ex:-RMR & RLR

35. Supranuclear control of ocular
movements:-
1. Saccadic system
2. Smooth pursuit system
3. Vergence system
4. Vestibular system
5. Optokinetic system
6. Position maintenance system

36.  Saccadic system:-
saccades are sudden,jerky,conjugate,movements
as the gaze shifts from one object to other.
 voluntary(normal)
 invoiuntary(peripheral,auditory,visual
stimuli)

37.  Smooth pursuit eye movements:-
 Tracking movements of eye as they follow moving
object
 Voluntary movements
 When the velocity of moving object inc. replaced by
small saccades(“catchup saccades”)

38.  Vergence movement:
 Allow focussing an object which moves away
from/towards observer.
 Very slow disjugate movements

39.  Vestibular eye movement:-
 Effective in compensating for effects of head
movements in disturbing visual fixation
 Through vestibular system

40.  Optokinetic system:-
 a movement following the moving scene , succeeded
by rapid saccade in opp.direction
 Position maintenance system:-
 Helps to maintain specific gaze by rapid micro
movements called “flicks” & slow micro movements
called “drifts”.

41. Bibilography
 Adler’s physiology of eye -11th edition
 Wolff’s anatomy of eye -8th edition
 Parson’s disease of eye-21st edition
 Jack.j.kanski brad bowlingclinical ophthalmology -
7th edition
 A.k.Khurana comprehensive ophthalmology -
5th edition