Lectures of Dr. Noura, Faculty of Medicine, Port Said University. Anatomy of the Orbit 2018

1. Anatomy of the orbit
By
Dr. Noura El Tahawy
Assist. Professor Of Anatomy
Embryology& Molecular Cell Biology
Faculty of Medicine, Port Said University,
Egypt

2. Specific objectives of orbit
Anatomy
1. List the contents of the orbit.
2. Mention intrinsic muscles of the eyeball.
3. Describe levator palpebrae superiosis & The extraocular
muscles (origin –insertion-action & nerve supply)
4. Describe sensory& motor nerves in the orbit.
5. Describe blood vessels in the orbit.
6. Describe ciliary ganglion.
7. List structures passing through the optic canal &the
sup.orbital fissures.

3. Bony orbit
Dr. Noura El Tahawy

4. Right Orbit Left Orbit
Nasal
Cavity
Superior Orbital Margin
Inferior Orbital Margin
Lateral Orbital Margin
Medial Orbital Margin

5. Apex
Roof
Floor

6. Orbital Plate of Frontal BoneLesser Wing of The Sphenoid
Roof of the orbit

7. The Frontal Process of Maxilla
The Lacrimal Bone
Orbital Plate
of
Ethmoid Bone
Orbital Process
of
Palatine Bone
Part of Body of The Sphenoid
Medial wall of orbit

8. Orbital Surface of Maxilla
Orbital Surface
of
Zygomatic Bone
Orbital Process
of
Palatine Bone
The Floor of the orbit

9. Foramina, Openings
and
Special Features of The Bony Orbit

10. Anterior
Ethmoidal Foramen
Posterior
Ethmoidal Foramen
Optic Foramen
Superior Orbital Fissure
Inferior Orbital Fissure
Zygomatic
Foramen
and
Canal
Zygomatico-facial
Foramen
Zygomatico-temporal
Foramen
Fossa
for
Lacrimal Sac
Fossa
for
Lacrimal Gland
Infra-orbital Groove
Infra-orbital Canal
Infra-orbital Groove

11. 1. Supraorbital notch
(foramen)
Forehead Supraorbital vessels & n.
2. Optic canal Middle cranial
fossa
CN. II, Ophthalmic a.
3. Sup. orbital fissure Middle cranial fossa CN. III, IV, V1, VI
Ophthalmic v.
4. Inf. orbital fissure Infratemporal fossa Infraorbital n. & vessels,
zygomatic n.
5. Posterior & anterior
ethmoidal foramen
Ethmoidal air cells Post & ant ethmoidal n.
& vessels
6. Zygomatic canal Zygomaticofacial &
Zygomaticotemporal n. &
vessels
7. Bony nasolacrimal
duct
Nasolacrimal duct
8. Infraorbital groove
& canal
Infraorbital n. & vessels
Orbital openings

12. Orbital openings

13. Orbital openings

14. ▪ Structures passing through the tendinous ring:
 Ophthalmic artery
 Optic nerve (C II)
 Both divisions of oculomotor n (C III).
 Nasociliary nerve (br. From ophthalmic division of trigeminal CV)
 Abducent nerve (C VI)
▪ Structures passing outside the tendinous ring:
 Trochlear nerve (C IV)
 Lacrimal nerve ((br. From ophthalmic division of trigeminal C V)
 Frontal nerve (br. From ophthalmic division of trigeminal C V)
 Maxillary nerve (second branch of trigeminal C V)
 Superior & inferior ophthalmic veins.

15. Contents of the orbit:
-Extraocular muscles
-Fat
-The eyeball
-Lacrimal apparatus
-Vessels:
1. Opthalmic branch of internal
carotid artery
2. Superior& inferior ophthalmic
veins: drain into cavernous
sinus
-Nerves:
1. Optic nerve.
2. Oculomotor (III), trochlear
(IV)& Abducent (VI).
3. Opthalmic division of
trigeminal (V).
4. Ciliary ganglion.

16. Coats of the Eye ball

19. Eyeball

20. A. External White Fibrous Coat
■ Consists of the sclera and the cornea.
1. Sclera
■ Is a tough white fibrous coat enveloping the posterior five-sixths of the eye.
2. Cornea
■ Is a transparent structure forming the anterior one-sixth of the external coat.
■ Is responsible for the refraction of light entering the eye.
B. Middle Vascular Pigmented Coat
■ Consists of the choroid, ciliary body, and iris.
1. Choroid
■ Consists of an outer pigmented (dark brown) layer and an inner highly vascular layer, which invests
the posterior five-sixths of the eyeball.
■ Nourishes the retina and darkens the eye.
2. Ciliary Body
■ Is a thickened portion of the vascular coat between the choroid and the iris and consists of the
ciliary ring, ciliary processes, and ciliary muscle.
The ciliary muscle consists of smooth muscle
innervated by parasympathetic fi bers derived from oculomotor.
3- Iris:
■ 1. Is a thin, contractile, circular, pigmented diaphragm with a central aperture, the pupil.
■ 2. Contains circular muscle fibers (sphincter pupillae), which are innervated by parasympathetic
fibers, and radial fibers (dilator pupillae), which are innervated by sympathetic fibers

21. 1. The conjunctiva is the delicate mucous membrane lining the inner surface of the lids from which it
is reflected over the anterior part of the sclera to the cornea. Over the lids it is thick and highly
vascular, but over the sclera it is much thinner and over the cornea it is reduced to a single layer
2. of epithelium. The line of reflection from the lid to the sclera is known as the conjunctival fornix;
the superior fornix receives the openings of the lacrimal glands.
3. Movements of the eyelids are brought about by the contraction of the orbicularis oculi and levator
palpebrae superioris muscles. The width of the palpebral fissure at any one time depends on the
tone of these muscles and the degree of protrusion of the eyeball.
C) The inner neural coat
• The retina is formed by an outer pigmented and an inner nervous layer
• Posteriorly the nerve fibres on its surface collect to form the optic nerve.
• its posterior pole there is a pale yellowish area, the macula lutea, the site of
• central vision, and just medial to this is the pale optic disc formed by the
• passage of nerve fibres through the retina, corresponding to the ‘blind spot’.
• The central artery of the retina emerges from the disc and then divides
• into upper and lower branches; each of these in turn divides into a nasal
• and temporal branch.
• The layer of ganglion cells, whose axons form the superifical layer of optic nerve fibres

22. Extraocular muscles

23. Orbital cavity

24. Orbital openings
Optic canalSuperior orbital fissure
Inferior orbital fissure

25. Origin: Levator palpebrae superiorismuscle
Tendinous ring

26. Levator palpebrae superioris muscle

27. Levator palpebrae superioris muscleTop view

28. Levator palpebrae superioris
muscle (insertion in the Eye Lid )

29. 4 Recti muscles

30. Superior rectus

31. Superior rectus

32. Superior rectus

34. lateral_rectus_muscle

35. Lateral rectus muscle

36. Lateral rectus muscle

37. Medial rectus muscle
Lateral

38. Medial rectus_muscle

39. Medial rectus muscle

40. Inferior rectus muscle

41. Inferior rectus muscle

42. Inferior rectus muscle

43. Extraocular muscles: obliques

44. Inferior rectus muscle

45. superior oblique muscle

46. superior oblique muscle

47. superior oblique muscle

48. Trochlea for superior oblique muscle

49. superior oblique muscle (trochlea)

50. Trochlea for superior oblique muscle

51. inferior oblique muscle

52. inferior oblique muscle

53. inferior oblique muscle

54. Origin of the 4 recti muscles
From the common tendinous ring around optic canal

58. Front view of extraocular muscles

59. 4
study Actions of the
Extra-ocular Muscles
&
eye movememts

61. 12 o’clock
Superior Rectus
Inferior Rectus
Superior Oblique
Inferior Oblique
Medial Rectus
Lateral Rectus
The PositionPrimary

62. Types of movements

64. Intrinsic muscles of the Eye

65. Intrinsic muscles of the Eye

66. Intrinsic muscles of the Eye

67. Ciliary muscle

68. Muscles of the Eye

70. Nerves of the Orbit
▪ Sensory nerves
 Optic nerve for vision
 ophthalmic division of trigeminal (CV) nerve for
general sensation
▪ Motor nerves
 Occulomotor nerve
 Trochlear nerve
 Abducent nerve
(The maxillary nerve passes through the inferior orbital fissure,
enters into the groove in floor of the orbit, continues as infraorbital
nerve, exits through infraorbital foramen and supplies the skin of
the face. Does not supply orbital contents)

71. Optic Nerve

72. Optic Nerve

73. Surrounded by meninges & the subarachnoid space
containing CSF
Optic Nerve

74. Optic Nerve
A rise in the CSF pressure within the cranial cavity is transmitted to the back of the eye
Runs
backward
& laterally
within the
cone of
the recti
muscles

75. Optic Nerve

76. Optic Nerve: Enters through optic canal

77. Optic Nerve

78. Optic Nerve

79. Optic Nerve
▪ Pierces the sclera at a point medial to the
posterior pole of the eyeball.
▪ Runs backward& laterally within the cone of
the recti muscles
▪ Enters through optic canal
▪ Accompanied by opthalmic artery that lies
below it
▪ Surrounded by meninges & the subarachnoid
space containing CSF

80. General sensory: Ophthalmic
division of trigeminal nerve

81. Ophthalmic nerve

82. Ophthalmic nerve

83. Lacrimal nerve (branch of ophthalmic n)

84. Frontal Nerve (br. Of ophthalmic n

85. Remove the orbital plate of the frontal bones and the frontal bone above the superior orbital
margin. Beneath the periorbita or periosteum lining the orbit, locate the frontal nerve, one of
the three branches of the ophthalmic divisionof trigeminal nerve. Frontal nerve splits into
supraorbital and supratrochlear nerves to supply the skin of the forehead.
Match to the diagram
1. Orbital plate of
frontal bone
(cut)Periorbita
2. Frontal n.
3. Supraorbital n
4. .Supratrochlear n.
2
4
3

86. Frontal Nerve

87. Frontal Nerve
Lacrimal nerve
Nasociliary nerve
Branches of ophthalmic division of
trigeminal (C V)
Sensory

88. Nasociliary nerve
Nasociliary Branche of ophthalmic
division of trigeminal (C V)
Sensory

91. Motor nerves of the orbit

92. Oculomotor nerve

94. Oculomotor nerve superior division

95. Oculomotor nerve superior division

96. Oculomotor nerve
superior division

97. oculomotor_nerve_inferior_division

98. Oculomotor nerve inferior division

99. Oculomotor supplies all extraocular muscles
except Lateral Rectus and superior Oblique

100. Trochlear nerve (C IV)

101. Trochlear nerve (C IV)

102. Trochlear nerve (C IV) in green

103. Trochlear nerve (C IV) in green

104. Trochlear nerve (C IV) in green

105. Superior
oblique
muscle
Trochlear
nerve

106. Trochlear N
Superior oblique

107. Abducent nerve (C VI)

111. Abducent nerve

112. Abducent
nerve
supplying
the Lateral
Rectus
muscle

114. Ciliary ganglion

115. Ciliary ganglion

118. Indicate the nerve supply to each.
V
III
IV VI
V1
V2
V3
II
Frontal n.
Supratrochlear n.
Supra-orbital n.
Lacrimal n.
Sensory nerves are branches of the
ophthalmic division of the trigeminal-
V1
V
III IV VI
II
VI
Nasociliary n.
Lacrimal n.
Ciliary ganglion
Short ciliary nn.
Ethmoidal nn.
Frontal n. (cut)
Infratrochlear n.
Long ciliary nn.
Motor nerves are branches of cranial nerves
III, IV, and VI

120. Vessels of the Orbit
▪ Arterial supply: Ophthalmic artery,
branch of internal carotid artery
 Venous drainage: Superior & inferior
ophthalmic veins, drain into the
cavernous sinus

121. Ophthalmic artery

122. Veins of the Orbit
Superior & inferior
ophthalmic veins:
▪ Drain the orbital
contents
▪ Pass through the
superior orbital
fissure
▪ Drain into the
cavernous sinus
▪ Communicates in
front with facial
vein
▪ Inferior
ophthalmic vein
communicates,
through the inferior
orbital fissure with
the pterygoid
venous plexus

123. There are NO lymph vessels
or lymph nodes in the
orbital cavity

124. Lacrimal Apparatus

126. Lacrimal Gland
■ Lies in the upper lateral angle of the orbit . Supplied by parasympathetic
fibers from facial nerve.
■ Is drained by 12 lacrimal ducts, which open into the superior conjunctival
fornix
.
B. Lacrimal Canaliculi
■ Are two curved canals that begin as a lacrimal punctum (or pore) in the
margin of the upper& lower eyelid and open into the lacrimal sac.
C. Lacrimal Sac
■ Lies in the lacrimal groove at anterior inferior angle of medial wall of the
orbit . It drains into nasolacrimal duct, which opens into the inferior
meatus of the nasal cavity.
D. Tears
■ Are produced by the lacrimal gland.
■ Pass through excretory ductules into the superior conjunctival fornix.
■ Are spread evenly over the eyeball by blinking movements
■ Enter the lacrimal canaliculi through their lacrimal puncta (which is on the
summit of the lacrimal papilla) then draining into the lacrimal sac,
nasolacrimal duct, and finally, the inferior nasal meatus in the nasal cavity.
Lacrimal Apparatus

127. End