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Lecture 1 orbit dr. noura

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

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Lecture 1 orbit dr. noura

  1. 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. 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. 3. Bony orbit Dr. Noura El Tahawy
  4. 4. Right Orbit Left Orbit Nasal Cavity Superior Orbital Margin Inferior Orbital Margin Lateral Orbital Margin Medial Orbital Margin
  5. 5. Apex Roof Floor
  6. 6. Orbital Plate of Frontal BoneLesser Wing of The Sphenoid Roof of the orbit
  7. 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. 8. Orbital Surface of Maxilla Orbital Surface of Zygomatic Bone Orbital Process of Palatine Bone The Floor of the orbit
  9. 9. Foramina, Openings and Special Features of The Bony Orbit
  10. 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. 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. 12. Orbital openings
  13. 13. Orbital openings
  14. 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. 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. 16. Coats of the Eye ball
  17. 17. Eyeball
  18. 18. 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
  19. 19. 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
  20. 20. Extraocular muscles
  21. 21. Orbital cavity
  22. 22. Orbital openings Optic canalSuperior orbital fissure Inferior orbital fissure
  23. 23. Origin: Levator palpebrae superiorismuscle Tendinous ring
  24. 24. Levator palpebrae superioris muscle
  25. 25. Levator palpebrae superioris muscleTop view
  26. 26. Levator palpebrae superioris muscle (insertion in the Eye Lid )
  27. 27. 4 Recti muscles
  28. 28. Superior rectus
  29. 29. Superior rectus
  30. 30. Superior rectus
  31. 31. lateral_rectus_muscle
  32. 32. Lateral rectus muscle
  33. 33. Lateral rectus muscle
  34. 34. Medial rectus muscle Lateral
  35. 35. Medial rectus_muscle
  36. 36. Medial rectus muscle
  37. 37. Inferior rectus muscle
  38. 38. Inferior rectus muscle
  39. 39. Inferior rectus muscle
  40. 40. Extraocular muscles: obliques
  41. 41. Inferior rectus muscle
  42. 42. superior oblique muscle
  43. 43. superior oblique muscle
  44. 44. superior oblique muscle
  45. 45. Trochlea for superior oblique muscle
  46. 46. superior oblique muscle (trochlea)
  47. 47. Trochlea for superior oblique muscle
  48. 48. inferior oblique muscle
  49. 49. inferior oblique muscle
  50. 50. inferior oblique muscle
  51. 51. Origin of the 4 recti muscles From the common tendinous ring around optic canal
  52. 52. Front view of extraocular muscles
  53. 53. 4 study Actions of the Extra-ocular Muscles & eye movememts
  54. 54. 12 o’clock Superior Rectus Inferior Rectus Superior Oblique Inferior Oblique Medial Rectus Lateral Rectus The PositionPrimary
  55. 55. Types of movements
  56. 56. Intrinsic muscles of the Eye
  57. 57. Intrinsic muscles of the Eye
  58. 58. Intrinsic muscles of the Eye
  59. 59. Ciliary muscle
  60. 60. Muscles of the Eye
  61. 61. 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)
  62. 62. Optic Nerve
  63. 63. Optic Nerve
  64. 64. Surrounded by meninges & the subarachnoid space containing CSF Optic Nerve
  65. 65. 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
  66. 66. Optic Nerve
  67. 67. Optic Nerve: Enters through optic canal
  68. 68. Optic Nerve
  69. 69. Optic Nerve
  70. 70. 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
  71. 71. General sensory: Ophthalmic division of trigeminal nerve
  72. 72. Ophthalmic nerve
  73. 73. Ophthalmic nerve
  74. 74. Lacrimal nerve (branch of ophthalmic n)
  75. 75. Frontal Nerve (br. Of ophthalmic n
  76. 76. 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
  77. 77. Frontal Nerve
  78. 78. Frontal Nerve Lacrimal nerve Nasociliary nerve Branches of ophthalmic division of trigeminal (C V) Sensory
  79. 79. Nasociliary nerve Nasociliary Branche of ophthalmic division of trigeminal (C V) Sensory
  80. 80. Motor nerves of the orbit
  81. 81. Oculomotor nerve
  82. 82. Oculomotor nerve superior division
  83. 83. Oculomotor nerve superior division
  84. 84. Oculomotor nerve superior division
  85. 85. oculomotor_nerve_inferior_division
  86. 86. Oculomotor nerve inferior division
  87. 87. Oculomotor supplies all extraocular muscles except Lateral Rectus and superior Oblique
  88. 88. Trochlear nerve (C IV)
  89. 89. Trochlear nerve (C IV)
  90. 90. Trochlear nerve (C IV) in green
  91. 91. Trochlear nerve (C IV) in green
  92. 92. Trochlear nerve (C IV) in green
  93. 93. Superior oblique muscle Trochlear nerve
  94. 94. Trochlear N Superior oblique
  95. 95. Abducent nerve (C VI)
  96. 96. Abducent nerve
  97. 97. Abducent nerve supplying the Lateral Rectus muscle
  98. 98. Ciliary ganglion
  99. 99. Ciliary ganglion
  100. 100. 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
  101. 101. Vessels of the Orbit ▪ Arterial supply: Ophthalmic artery, branch of internal carotid artery  Venous drainage: Superior & inferior ophthalmic veins, drain into the cavernous sinus
  102. 102. Ophthalmic artery
  103. 103. 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
  104. 104. There are NO lymph vessels or lymph nodes in the orbital cavity
  105. 105. Lacrimal Apparatus
  106. 106. 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
  107. 107. End