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Orbit Anatomy and Surgical Spaces

The Orbit Anatomy and Surgical Spaces

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Orbit Anatomy and Surgical Spaces

  1. 1. DR. VIKAS KHATRI DNB Resident Sadguru Netra Chikitsalaya
  2. 2. Quadrangular truncated pyramids Situated between the anterior cranial fossa above and the maxillary sinus below. ORBIT ANATOMY Anterior Cranial Fossa Maxillary Sinus Orbit
  3. 3. 40mm 35mm Orbital Index = 𝐇𝐞𝐢𝐠𝐡𝐭 𝐖𝐢𝐝𝐭𝐡 𝐗 𝟏𝟎𝟎 It Shows Racial Variation. Megasenes - Greater than 89 ( Orientals ) Mesosenes - Between 83 and 89 ( Caucasians ) Microsenes - Less than 83 ( Blacks ) Volume of Orbit is about 29ml Ratio between volume of Orbit and and of the Eyeball is 4.5 : 1
  4. 4. Frontal Bone
  5. 5. Frontal Bone
  6. 6. Ethmoid Bone
  7. 7. Ethmoid Bone
  8. 8. Lacrimal Bone
  9. 9. Lacrimal Bone
  10. 10. Zygomatic Bone
  11. 11. Zygomatic Bone
  12. 12. Sphenoid Bone
  13. 13. Sphenoid Bone
  14. 14. Maxillary Bone
  15. 15. Maxillary Bone
  16. 16. Frontal Process of Maxilla Lacrimal Bone Orbital plate of ethmoid bone Body of sphenoid
  17. 17. Lacrimal Fossa – Boundaries : Anteriorly by – Anterior Lacrimal Crest of the Maxillary bone Posteriorly by – Posterior Lacrimal Crest of lacrimal bone Lacrimal Sac along with its fascia lies in the lacrimal fossa Anterior Lacrimal Crest of the Maxillary bone Posterior Lacrimal Crest of the lacrimal bone Just behind the Posterior lacrimal Crest following structures have their attachment : • Horners Muscle • Septum orbitale • Check Ligament of Medial Rectus Muscle
  18. 18. RELATIONS MEDIAL TO THE MEDIAL WALL
  19. 19. Medial Orbital Wall is the thinnest wall- 1. Ethmoiditis is the most common cause of orbital cellulitis 2. Easily fractured during trauma and orbitotomy operation During Surgery along Medial orbital wall Hemorrhage is most troublesome due to injury to ethmoidal vessel.
  20. 20. Greater Wing of Sphenoid Bone ; Posteriorly Zygomatic Bone ; Anteriorly
  21. 21. Anteriorly, In Zygomatic Bone there is Bony Projection known as THE LATERAL ORBITAL TUBERCLE OF WHITNALL It Gives attachment to : • Lateral check ligament Suspensory ligament of eyeball • Aponeurosis of levator palpebrae superioris • Lacrimal fascia • Orbital septum • Lateral canthal tendon
  22. 22. LATERAL WALL OF ORBIT Laterally, Lateral Wall Separates Orbit from Temporal Fossa Anteriorly and Middle Cranial Fossa Posteriorly Medially , Lateral Wall of Orbit is related to • Lateral Rectus Muscle • Lacrimal Nerves and Vessel • Zygomatic Nerves and Vessel
  23. 23.  Lateral orbital wall protects only the posterior half of the orbit.  Anterior half is not covered by bone. Hence, palpation of the retrobulbar tumour is easier from the lateral side.
  24. 24. Orbital Plate of Frontal Bone Lesser Wing of Sphenoid
  25. 25. Anterolateral Part of roof Foosa for Lacrimal gland At the Junction of Roof and Medial Wall Trochlear Fossa for the Pulley of Superior Oblique Muscle Lacrimal Artery and Vein
  26. 26. Orbital Plate of Maxilla Orbital Surface of Zygomatic Bone Palatine Bone
  27. 27. Inferior orbital groove Inferior Oblique Muscle Inferior orbital fissure Inferior Rectus Muscle Infraorbital Foramen
  28. 28.  Involved in blow out fracture of the orbit  Invaded by tumors of the maxillary antrum  Floor Of Orbit is best visualised with standard Posteroanterior Radiographs
  29. 29. Blow out fracture of the orbit Posteroanterior Radiographs of Orbit with Tear Drop Sign
  30. 30. Posterior End of Orbit Apex has two Orifice  Optic Canal  Superior Orbital Fissure
  31. 31. Superior Orbital Fissure Bounded by Lesser and Greater Wing of Sphenoid Lateral to Optic Canal Divided into Upper, Middle and Lower parts by Common Tendinous Ring
  32. 32. Frontal Nerve Trochlear Nerve Lacrimal Nerve Structure passing Superior Orbital Fissure Superior Ophthalmic Vein Superior branch of oculomotor nerve Abducent nerve Nasociliary nerve Inferior branch of oculomotor nerve UPPER PART MIDDLE PART
  33. 33. Optic Canal Connects Orbit to Middle Cranial Fossa Transmits : Optic Nerve Ophthalmic Artery Average length – 6mm to 11mm Orbital end – Vertically Oval (6x4.5mm) Middle Part – Circular (5x5mm) Cranial Part Horizontally Oval (4.5x6mm) Optic Nerve Ophthalmic Artery
  34. 34. Syndromes – a) TOLOSA HUNT SYNDROME- Inflammation of the apex (idiopathic) Ophthalmoplegia, Diplopia, Headaches, Dizziness, Nausea, Neck stiffness, Photophobia, Blurred vision b) SUPERIOR ORBITAL FISSURE SYNDROME- Fracture of superior orbital fissure Involvement of cranial nerves(Optic Nerve is spared) Diplopia, Ophthalmoplegia, Ptosis, Proptosis
  35. 35. c) ORBITAL APEX SYNDROME Infection, Inflammatory, Trauma, Tumor, Involvement of cranial nerves – optic nerve (II), oculomotor nerve (III), trochlear nerve (IV), abducens nerve (VI), and/or the ophthalmic branch of the trigeminal nerve (V1) Visual loss, Diplopia, Ophthalmoplegia, Ptosis, Proptosis, Chemosis
  36. 36. Anterior open end of the orbit Formed by the orbital margins
  37. 37. Superior orbital margin Formed by frontal bone Contains : Supraorbital Notch : Transmitting the supraorbital nerve Supratrochlear groove : 10mm medial to supraorbital notch transmitting Supratrochlear nerve and artery Supraorbital Notch Supratrochlear groove
  38. 38. Inferior orbital margin Formed by - Maxilla (medially) - Zygomatic bone (laterally) At the junction of medial 1/3rd and lateral 2/3rd is a depression for the origin of inferior oblique Prone to fracture Disruption of the inferior oblique Diplopia Infraorbital foramen 4-5 mm below infraorbital margin in line with supraorbital foramen
  39. 39. Medial orbital margin Formed of - Anterior lacrimal crest on Frontal process of maxilla (Below) - Frontal bone (Above)
  40. 40. Lateral orbital margin # Formed by - Zygomatic bone - Zygomatic process of frontal bone # Frontozygomatic suture Narrowest and weakest part Prone to separation by trauma # It does not reach as far anterior as medial margin, therefore anterior half of globe is not protected by bone.
  41. 41. Orbital periosteum Gives out two processes- a) Lacrimal fascia (encloses lacrimal sac) b) A process holding the trochlea Extent of the periorbita- Anteriorly -continues as periosteum at the orbital margin giving off a stratum to the orbital septum. Posteriorly -unites with the dura mater and the sheath of optic nerve
  42. 42. Loosely adherent to Bone but Firmly adherent to : • Orbital Margin • Orbital Fissure • Optic canal • Lacrimal fossa • Sutures. Significance - Orbital roof surgery in the areas of fissures and sutures may lead to CSF leakage
  43. 43. Elastic and vascular connective surrounding entire globe except the cornea. Extends from perilimbal sclera to the optic nerve fusing with its dural sheath. Tenons Capsule is separated from sclera by Episcleral Space (Tenons Space) and contains fine trabeculae which connects sclera with tenons capsule. Tenons Capsule Tenons Space Sclera
  44. 44. Thickened inferiorly to form suspensory ligament of Lockwood Expansions of Tenon’s capsule- a) Lateral check ligament b) Medial check ligament c) Sleeves around the extraocular muscles
  45. 45. Structures piercing Tenons Capsule- a)Ciliary vessels and nerves b)Venae vorticosae at equator c)Extraocular Muscle Tenons Capsule Venae Vorticosae Extraocular Muscle Ciliary Nerves & Vessels
  46. 46. Subperiosteal Space Peripheral Orbital Space Sub-Tenons Space Central Space
  47. 47. Space between Orbital bone and Periorbita. Subperiosteal Space
  48. 48. Peripheral Orbital Space Bounded peripherally by periorbita and internally by extraocular muscle and intermuscular septum • Tumors in this space produce eccentric proptosis • Peribulbar Block is given in this Space
  49. 49. Central Space Bounded anteriorly by Tenons Capsule and peripherally by Extraocular muscle and their intermuscular septa Tumours produces Axial Proptosis Also known as Muscular Cone or Retrobulbar Space Contents of Central Space • Optic Nerve • Oculomotor Nerve • Abducent Nerve • Nasociliary Nerve • Ciliary Ganglion • Ophthalmic Artery • Superior Ophthalmic Vein • Central Orbital Fat
  50. 50. Sub-Tenons Space Space between the Sclera and Tenons Capsule Sub-Tenon Injection is given in this space Pus collected in this space is drained by incision of Tenons Capsule through the Conjuctiva
  51. 51. Supratrochlear Nerve Supraorbital Nerve Lacrimal Nerve Frontal Nerve Trochlear Nerve
  52. 52. Infratrochlear Nerve Long ciliary nerves Short ciliary nerves Ciliary Ganglion Abducent Nerve Oculomotor Nerve
  53. 53. Supraorbital Artery Lacrimal Artery Posterior Ciliary Artery Central Retinal Artery Ophthalmic Artery Supratrochlear Artery
  54. 54. Supratrochlear Vein Supraorbital Vein Superior Ophthalmic Vein Vorticose veins Cavernous Sinus Inferior Ophthalmic Vein
  55. 55. Thank You

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