1. Extraocular Muscles

2. Muscles of the orbit: 1.Voluntary muscles: They are : A. Four Recti :
Superior rectus
Inferior rectus
Medial rectus
Lateral rectus
B. Two oblique :
Superior oblique
Inferior oblique
C. The levator palpebrae superioris elevates the upper eyelid

3. 2.Involuntary muscles:
Superior tarsal
Inferior tarsal &
Orbitalis

4. Extrinsic muscles of eyeball:
These consists of four recti and two oblique muscles:
Superior rectus
Inferior rectus
Medial rectus
Lateral rectus
Superior oblique
Inferior oblique

5. Recti muscles: Origin:
All four recti arise in the posterior part of the orbit from the common tendinous ring which bridges across the superior orbital fissure

6. Insertion:
All the recti muscles proceed forward and inserted in front of the equator of the eyeball and behind the sclero-corneal junction

7. Oblique muscles: Superior oblique: Origin:
Common tendinous ring
Superior oblique:
Origin:
Superior oblique
It arises from the undersurface of the lesser wing above and medial to the common tendinous ring

8. Insertion:
Common tendinous ring
Medial rectus
Superior rectus
The tendon of the muscle passes through a fibro-cartilaginous pulley and is inserted into the sclera behind the equator in postero-superior quadrant of the eyeball
Superior oblique

9. Inferior oblique: Origin:
It arises from the orbital surface of maxilla in the floor of the orbit
Inferior oblique

10. Insertion:
Inserted into the sclera behind the equator in the postero-superior quadrant of the eyeball
Lateral rectus
Inferior rectus
Inferior oblique

11. Nerve supply:
All striated ocular muscles are supplied by the Oculomotor nerve except the lateral rectus and superior oblique
The Lateral rectus is innervated by the Abducent nerve
The Superior oblique is innervated by the Trochlear nerve
S O4; L R6

13. Axes of movements: 1.Elevation and depression of eyeball:
Takes place around transverse axis passing through the equator
2.Adduction and abduction:
Takes place around a vertical axis passing through the equator
3.Torsion of eyeball: (Intorsion & Extorsion)
Takes place around antero-posterior axis extending from anterior pole to posterior pole

14. Axes of movements:
Depression
Elevation
Transverse axis

15. Axes of movements:
Adduction
Abduction
Vertical axis

16. Axes of movements:
Extorsion
Intorsion
Antero-posterior axis

17. Action of individual muscles:
MEDIAL
LATERAL
Elevation
Superior rectus
Inferior oblique A B D U C T I O N A D U C T I O N
Extorsion
Intorsion
Lateral rectus
Medial rectus
Extorsion
Intorsion
superior oblique
Inferior rectus
Depression

19. Eye movements produced by muscles:
No movement is done by a single muscle, while some muscle acts as a prime movers and other acts as synergists
MOVEMENT
MUSCLE
Adduction
Medial rectus, assisted by superior and inferior recti
Abduction
Lateral rectus, assisted by the superior and inferior oblique muscles
Elevation
Superior rectus and inferior oblique muscles
Depression
Inferior rectus and superior oblique muscles
Intorsion
Superior rectus and inferior oblique
Extorsion
Inferior rectus and inferior oblique

20. Associated movements of eyeball:
Normally both eyes move simultaneously and to an equal extent. These associated movements may be conjugate or disjugate
1.Conjugate movements:
It occurs when both eyes moves in same direction
Dextro-duction and leavo-duction: Turning both eyes respectively towards right and left sides, around a transverse axis

21. Superduction and subduction: both eyes moving respectively above and below, around a transverse axis
2.Disjugate movements:
Takes place when the axes of both eyes converge or diverge
Convergence or divergence: when both eyes move around a vertical axis

22. Antero-posterior stability:
Factors maintaining the stability of eyeball:
Antero-posterior stability:
Balanced action of four recti pulling from behind, and two oblique muscles from front
Check ligaments of medial and lateral recti prevents from posterior displacement
Orbital fat

23. Vertical stability:
It is maintained by the suspensory ligament of eyeball of Lockwood

24. Levator palpebrae superioris:
It is a triangular sheet of muscle which intervenes between the roof of the orbit and superior rectus muscle
Origin:
Levator palpebrae superioris
It arises from undersurface of lesser wing of the sphenoid bone

25. Insertion:
The muscle ends in an aponeurosis by splitting into three lamellae

26. Nerve supply:
Oculomotor nerve
Action:
It elevates the upper eyelid

27. These are Superior tarsal, Inferior tarsal and Orbitalis muscle
2.Involuntary muscles:
These are Superior tarsal, Inferior tarsal and Orbitalis muscle
Superior tarsal:
It is derived from the intermediate lamella of levator palpebrae superioris and is attached to superior tarsus
It assists in elevation of upper eye lid

29. Inferior tarsal:
- It connects the inferior tarsus of lower eyelid to the fascial sheet of inferior rectus and inferior oblique
- It assists in depression of lower eyelid
Orbitalis:
- It streches across the inferior orbital fissure

31. Applied Anatomy:
Weakness or paralysis of a muscle causes squint/strabismus. In this condition the two eyes appear to look in different directions
Nystagmus is characterised by involuntary oscillatory movements of the eyes. This in due to incordination of the ocular muscles

32. PARASYMPATHETIC GANGLIONS

33. Parasympathetic ganglion:
They are four peripheral parasympathetic ganglion:
Ciliary ganglion
Submandibular ganglion
Otic ganglion
Pterygopalatine ganglion

34. i. Ciliary ganglion:
It is topographically connected to Nasociliary nerve but functionally connected with the oculomotor nerve
It contains the cell bodies of multipolar neuron
Nasociliary nerve
Ciliary ganglion

35. Situation:
The ganglion is situated near the apex of the orbit, between the optic nerve and the origin of lateral rectus muscle
Ciliary ganglion

36. Connections:
The posterior border of the ganglion is connected with three roots: Motor, Sensory and Sympathetic

37. a. Parasympathetic/Motor root:
The motor root is derived from the nerve to inferior oblique

38. b. Sensory root:
It is derived from the nasociliary nerve. It conveys fibers from the eyeball and pass through Ciliary ganglion. It is concerned with pain, touch and thermal sensations from the eyeball

39. c. Sympathetic root:
It is derived from a branch of internal carotid plexus. It conveys post-ganglionic fibers from the superior cervical sympathetic ganglion

41. Branches:
Anterior border of the ganglion provides about 8-10 short ciliary branches which contains fibers from all the roots.
Short ciliary nerves

42. ii. Submandibular ganglion:
It is topographically connected to lingual nerve but functionally connected with the facial nerve and chorda tympani
It is relay station for submandibular and sublingual salivary gland
The ganglion presents parasympathetic sympathetic and sensory roots distributing branches

43. Parasympathetic root/motor root:
The posterior root connecting the ganglion with the lingual nerve forms the parasympathetic root
Sympathetic root:
It is derived from the plexus around the facial artery
Sensory root:
It reaches the gland through lingual nerve

45. iii. Otic ganglion:
It is situated in the infratemporal fossa and topographically connected with the mandibular nerve but functionally connected with the glossopharyngeal nerve

46. Situation:
The ganglion lies immediately below the foramen ovale.

47. Connections: a. Parasympathetic/Motor root:
It is derived from lesser petrosal nerve
b. Sympathetic root:
It is derived from the plexus around the middle meningeal artery and conveys postganglionic fibers from the superior cervical ganglion
c. Sensory root:
The sensory root comes from the auriculo temporal nerve and is sensory to parotid gland

50. Branches:
Post-ganglionic parasympathetic fibers arising from the ganglion join the auriculo-temporal nerve and supply the secreto-motor fibers to the parotid gland
Post-ganglionic sympathtic fibers, which pass through the ganglion without interruption, join the auriculo-temporal nerve and provide mainly vaso-motor to parotid galnd

52. c. Fibers from the nerve to medial pterygoid pass through the ganglion without interruption, and supply the tensor veli palitini and tensor tympani muscles
d. The otic ganglion is connected to the chorda tympani nerve and the nerve to pterygoid canal, this communicating channel possibly forms an alternate route of taste pathway from the anterior two-third of the tongue to the geniculate ganglion of facial nerve

54. iv. Pterygo-palatine ganglion:
It is the largest peripheral parasympathetic ganglion and occupies the deepest part of the pterygo-palatine fossa
Topographically the ganglion is intimately related to the maxillary nerve but functionally it is connected with greater petrosal branch of facial nerve

55. Situation:
The ganglion is situated lateral to spheno-palatine foramen, below the maxillary nerve and in front of the pterygoid canal

56. Connections: a. Parasympathetic/Motor root:
It is derived from nerve of pterygoid canal
b. Sympathetic root:
It is derived from deep petrosal nerve
c. Sensory root:
It is derived from maxillary nerve and passes through the ganglion without interruption

59. Branches:
The branches of the ganglion are actually branches of the maxillary nerve. They also carry parasympathetic and sympathetic fibers which pass through the ganglion. The branches are:
Orbital branches
Palatine branches: Greater and lesser palatine
Nasal branches: Postero-superior lateral nasal and medial nasal branches
Pharyngeal branch