The document discusses the extraocular muscles of the eye. It describes the four rectus muscles - superior, inferior, lateral and medial rectus muscles. It also describes the two oblique muscles - superior and inferior oblique muscles. It discusses the origins, insertions and actions of each muscle. It further discusses the nerve supply, axes of movements and individual muscle movements. Factors maintaining stability of the eyeball are also summarized.

1. EXTRA-OCULAR
MUSCLES
DR. SUNDIP CHARMODE
ASSISTANT PROFESSOR

2. INTRODUCTION
 Voluntary (Striated) Extrinsic Muscles :
1. Four Recti
2. Two Oblique
 Involuntary (smooth) Intrinsic muscles :
1. Superior Tarsal
2. Inferior Tarsal
3. Orbitalis

5. EXTRINSIC / EXTRAOCULAR
 Four Recti
1. Superior rectus
2. Inferior rectus
3. Lateral rectus
4. Medial rectus
 Two Oblique
1. Superior oblique
2. Inferior oblique

6. RECTI MUSCLES
• Origin :
• Arise from posterior part of orbit from the
Common Tendinous Ring.

7. RECTI MUSCLES
• Insertion : They proceed forward in a cone of
muscles and spread out at the sites of insertion
into the sclera.
• They are inserted in front of the equator of eyeball
and behind the sclero-corneal junction.
• Medial rectus : 5mm
• Inferior rectus : 6mm
• Lateral rectus : 7mm
• Superior rectus : 8mm

9. OBLIQUE MUSCLES

10. SUPERIOR OBLIQUE
 Origin : arises from undersurface of Lesser wing
of sphenoid above and medial to the Common
Tendinous ring.
 Insertion : Sclera behind the equator in the
postero-superior quadrant of the eyeball.

11. INFERIOR OBLIQUE
 Origin : arises from orbital surface of maxilla in
the floor of orbit, slightly lateral to the naso-
lacrimal notch.
 Insertion : Sclera behind the equator in the
postero-superior quadrant of the eyeball close to
the superior oblique.

14. NERVE SUPPLY
 All striated ocular muscles are supplied by
Oculomotor nerve except Lateral rectus and
Superior oblique.

15. AXES OF MUSCLES
 Medial and lateral rectus lie in same horizontal
plane.
 Superior and Inferior recti are situated in same
oblique plane, directed forwards and laterally
making an angle of 25* with optical axis.
 Oblique muscles lie in same oblique plane
directed backwards and laterally making an
angle of 51* medial to optical axis.

16. AXES OF MOVEMENTS
 Elevation and depression – around a transverse
axis passing through equator.
 Adduction and abduction - around a vertical
axis passing through the equator.
 Torsion of eyeball – around an antero-posterior
axis

17. INDIVIDUAL MUSCLE MOVEMENTS
 Medial rectus : Adduction only
 Lateral rectus : Abduction only

18. SUPERIOR RECTUS
 In primary position :
• Elevation, adduction and Intorsion
 In adducted eye : Intorsion only
 In abducted eye : Elevation only

19. INFERIOR RECTUS
 In Primary position :
• Depression, adduction and Extorsion
 In adducted eye : Extorsion only
 In abducted eye : Depression only

20. SUPERIOR OBLIQUE
 In Primary position :
• Depression, abduction and Intorsion
 In adducted eye : Depression only
 In abducted eye : Intorsion only.

21. INFERIOR OBLIQUE
 In Primary position :
• Elevation, abduction and Extorsion
 In adducted eye : Elevation only
 In abducted eye : Extorsion only

22. EYE MOVEMENTS BY MUSCLES
 Adduction :
 Abduction :
 Elevation :
 Depression :
 Intorsion :
 Extorsion :

23. YOKE MUSCLES
 They are contralaterally paired extra-ocular
muscles that work synergistically to direct the
gaze in a given direction.
 For example :

24. SHERRINGTON’S LAW OF RECIPROCAL
INNERVATION
 Whenever an agonist receives an impulse to
contract, an equivalent inhibitory impulse is
sent to its antagonist which relaxes and
actually lengthens.

25. TERMINOLOGY
1. Agonist - prime mover
2. Antagonist – acts in opposition
3. Synergist – two muscles moving the eye in
same direction.
4. Yoke muscles – contralateral synergists

26. ASSOCIATED MOVEMENTS BY
EYEBALL
 Conjugate movements : Both eyes move in
same direction with visual axes parallel.
• Dextro-duction - to right
• Laevo-duction – to left
• Super-duction - above
• Sub-duction - below

27. ASSOCIATED MOVEMENTS BY
EYEBALL
 Disjugate movements – when the axes of both
eyes converge or diverge.
• Convergence & Divergence –
• Sursumvergence -

28. FACTORS MAINTAINING STABILITY
OF EYEBALL
1. Antero-posterior stability :
2. Vertical stability :

29. ANTERO - POSTERIOR
STABILITY
1. Balanced action of four recti pulling from
behind and two obliques pulling from front.
2. Check ligaments of medial and lateral recti.
3. Orbital fat

30. VERTICAL STABILITY
 It is maintained by Suspensory ligament of
eyeball (of Lockwood), which is derived from
Fascia bulbi / thickening of Tenon’s capsule and
extends from check ligaments of medial, lateral
and inferior recti.

33. LEVATOR PALPEBRAE SUPERIORIS
 Origin :
• Arises from undersurface of lesser wing of
sphenoid above the common ring and superior
rectus muscle.

34. LEVATOR PALPEBRAE SUPERIORIS
 Insertion : passes forwards, forms broad and
fleshy with :
• Medial straight margin : blends with Medial
Palpebral ligament
• Lateral concave margin : Whitnall’s tubercle
of zygomatic bone.

35. LEVATOR PALPEBRAE SUPERIORIS
• Upper lamella : It penetrates orbital septum,
passes through orbicularis oculi muscle, & is
attached to the skin of upper eyelid.
• Intermediate lamella : forms Superior tarsal
muscle which is attached to the upper margin
of superior tarsus.
• Lower lamella : derived from conjoint
connective of LPS & SR and is inserted into
Superior Fornix of conjunctiva.

37. LEVATOR PALPEBRAE SUPERIORIS
 Nerve supply : Upper division of Oculomotor
nerve
 Action : Elevates upper eyelid.

38. INTRINSIC
EXTRA-OCULAR
MUSCLES

39. SUPERIOR TARSAL
• It is derived from the intermediate lamella of
LPS and is attached to upper margin of
Superior tarsus.
• It assists in elevation of upper eyelid.

40. INFERIOR TARSAL
 It connects the inferior tarsus of lower eyelid
to the fascial sheath of Inferior Rectus muscle
and Inferior Oblique.
 It assists in depression of lower lid.

41. ORBITALIS
 It stretches across the Inferior Orbital fissure.

42. APPLIED ANATOMY
 Unilateral paralysis of individual muscle d/t
involvement of nerve produces squint
/strabismus.
 It may result in diplopia.
 Paralysis of Lateral rectus – Internal
strabismus
 Paralysis of Medial rectus – External
strabismus

43. CILIARY
GANGLION

44. INTRODUCTION
• Peripheral, parasympathetic ganglion
• Topographically – naso-ciliary nerve
• Functionally – oculomotor nerve
• Size: Pin head

45. SITUATION
• Near apex of orbit
• Lies between optic nerve and origin of lateral
rectus
• Ophthalmic artery lies medial to the ganglion

48. CONNECTIONS
• Posterior border of ganglion is connected
with:
• Motor/Parasympathetic root
• Sympathetic root
• Sensory root

50. PARA-SYMPATHETIC ROOT
• Preganglionic fibers – arise from Edinger-
westphal nucleus and pass through the nerve
of inferior oblique, synapse in ganglion
• Post ganglionic fibers- pass through short
ciliary nerves and supply ciliary muscle and
sphincter dilator

51. SYMPATHETIC ROOT
• Preganglionic fibers - arise from neurons in
the intermedio-lateral column of the thoracic
spinal cord, at the level of first and second
thoracic spinal segments. Synapse in superior
cervical ganglion
• Postganglionic fibers – ascend with
the internal carotid artery as a plexus of
nerves, the carotid plexus.

52. SYMPATHETIC ROOT
• Pass uninterrupted through ciliary ganglion,
along short ciliary nerves – supply blood
vessels of eyeball and dilator pupillae.

53. SENSORY ROOT
• Derived from naso-ciliary nerve, containing
sensory fibers from eyeball
• Pass through ciliary ganglion uninterrupted
• Deals with pain, touch and thermal sensations
of eyeball.

54. BRANCHES
• Anterior border of ciliary ganglion – 8- 10
short ciliary branches (containing fibers from
all three roots)
• Pass in two bundles, run above and below
optic nerve, subdivide into 15-20 branches
• Pierce sclera around optic nerve, pass
between sclera and choroid.
• The fibers contain -

55. OPTIC NERVE

57. INTRODUCTION
• Second cranial nerve
• Each starts from optic disc and extends up
to optic chiasma
• Backward continuation of nerve fiber layer
of retina which consists of axons arising
from ganglionic cells of retina

58. FUNCTIONAL COMPONENTS
1. Special somatic afferent fibers for vision
2. Afferents for pupillary light and accommodation
reflexes
3. A few unknown efferent

59. PECULARITIES
• Neither a true cranial nerve, nor a peripheral
nerve
• Morphologically and embryologically, optic
nerve is comparable to sensory tract of white
matter of brain
• Covered by meninges
• Devoid of neurolemma sheath and
endoneurium and is supported by neuroglial
cells. Does not regenerate.

60. MEASUREMENTS
• Total length -47-50
mm
• Intra-ocular part: 1
mm
• Intra-orbital part: 30
mm
• Intra-canalicular part:
6-9 mm
• Intra-cranial part: 10
mm

62. GENERAL COURSE OF OPTIC NERVE
• Begins at optic disc where the fibers of stratum
opticum converge
• Pierces outer layers of retina, choroid, lamina
cribrosa sclerae at 3 mm nasal to the posterior pole.
• Acquires the myelin sheath during passage
• Pass backwards and medially through the orbital
cavity and optic canal
• Joins with optic chiasma in cranial cavity

64. INTRA-OCULAR PART
• Divided into four portions from anterior to
posterior
1. Surface nerve fiber layer
2. Prelaminar layer
3. Lamina cribrosa
4. Retrolaminar

66. INTRA-ORBITAL PART - FEATURES
• Extends from back of eyeball to the optic foramina
• Sinuous course so as to allow eye movements
• Covered by all three meningeal layers
• Pial sheath carrying blood vessels project septa into
substance of nerve dividing it into fasciculi

67. INTRA-ORBITAL PART - RELATIONS
• Posteriorly: surrounded by four recti muscles
• Anteriorly: separated from the cone of muscles by
fat, in which runs ciliary vessels and nerves
• Laterally: Ciliary ganglion between the proximal part
of lateral rectus and optic nerve
• Infero-medially: pierced by central artery and vein of
retina, about 12 mm behind the eyeball.

69. INTRA-ORBITAL PART-RELATIONS
• Above: crossed by nasociliary nerve, ophthalmic
artery and superior ophthalmic vein (from lateral to
medial)
• Below: crossed by the nerve to the medial rectus,
from the inferior division of oculomotor nerve.

71. INTRA-CANALICULAR PART -
RELATIONS
• Closely related to ophthalmic artery
• Infero-laterally: Ophthalmic artery
• Medially: Sphenoidal and posterior ethmoidal
sinuses separated by a thin plate of bone
• Inflammation from these sinuses may produce retro-
bulbar neuritis

73. INTRA-CRANIAL PART- RELATIONS
• Extends from optic canal to optic chiasma
• Above: Posterior part of olfactory tract and gyrus
rectus, anterior cerebral artery
• Laterally: Internal carotid artery

75. BLOOD SUPPLY OF OPTIC NERVE
• The arteries are derived from two sources:
1. From the Plexus in the Pial sheath which is
contributed by
1. Superior hypophyseal artery
2. Ophthalmic artery
3. Posterior ciliary artery
4. Extra-neural branches of central artery
2. From Intra-neural branches of Central artery
Venous blood drains into central vein

76. CLINICAL CORRELATION
1. Complete lesion of one optic nerve is manifested
by the following:
a. Total blindness of corresponding eye
b. Loss of direct light reflex on affected eye and
consensual light reflex on sound eye
c. Retention of direct light reflex of sound eye and
consensual light reflex on affected eye
d. Accommodation reflex remains unaffected

77. CLINICAL CORRELATION
2. A tumour affecting the base of frontal lobe, it may
press upon the optic nerve and is manifested by-
a. Optic atrophy on affected side due to pressure
b. Choked disc on sound side due to increased intracranial
tension. The phenomenon is called as Foster Kennedy
syndrome
3. Congenital anomalies
1. Coloboma of optic disc
2. Drusen of optic disc
3. Hypoplasia of optic disc

78. CLINICAL CORRELATION
4. Optic neuritis
5. Anterior ischemic optic neuropathy
6. Papilloedema
7. Tumours –
1. Optic nerve gliomas
2. Optic nerve sheath meningiomas

79. THANKS