Superior Orbital Fissure 360°

1. SOF 360° 12-12-2014

2. Anterior to L-OCR is Superior Orbital Fissure

3. Yellow line = “nasal” part of SOF Clinically, the SOF and CS apex represents a continuum.

4. SOF is the space between two Structs – Superiorly OS [ Optic Strut ] & Inferiorly MS [ Maxillary Strut ]

5. SOF is the space between two Structs – Superiorly OS [ Optic Strut ] & Inferiorly MS [ Maxillary Strut ]

6. SOF is the space between two Structs – Superiorly OS [ Optic Strut ] & Inferiorly MS [ Maxillary Strut ] - So, from an endoscopic endonasal viewpoint the nasal window to SOF is above V2, and below the lateral optico -carotid recess. Anterior view of SOF Posterior view of SOF

7. SOF - Anterior

8. SOF - Posterior

9. The term cavernous sinus addresses only the venous aspect, neglecting the neural and soft tissue components . A more comprehensive and rational term is lateral sellar compartment (Parkinson 1990 ) . Lateral sellar compartment ( = Cavernous sinus ) is in continuation with SOF & Orbit SOF devided into ALSC = Anterior lateral sellar compartment – Located anterior to the anterior loop of the cavernous portion of the internal carotid artery. Orbital apex

10. Lateral sellar compartment ( = Cavernous sinus )

11. Lateral sellar compartment ( = Cavernous sinus )

12. ALSC ( Anterior lateral sellar compartment )

13. Parts of ALSC ( Anterior lateral sellar compartment ) Superior Part – Nervous compartment Lateral Group of nerves - from lateral to medial - LFT [ Liver functional tests ] Menumonic – Lacrimal N., Frontal N., TrochlearN . Middle Group of nerves - 3 rd , 6 th , Nasocilliary N . Inferior part – Venous compartment - Inferior Opthalmic vein – The inferior venous compartment is given by the confluence of the superior ophthalmic vein ( SOV ) and inferior ophthalmic vein ( IOV ), which drain into the cavernous sinus ( Froelich et al. 2009 ) .

14. Zonule of zinn - inserts on the infraoptic tubercle, which is often found as a canal located beneath the optic strut . The four rectus muscles insert posteriorly, through the Inferior common tendon ( ICT ) , on the infraoptic tubercle, a small depression below the optic strut.

15. More anteriorly, the Inferior common tendon ( ICT ) splits into a superior and inferior tendon. From the inferior tendon originate the medial, inferior, and lateral rectus muscles, and from the superior originates the superior rectus muscle. Inferior common tendon ( ICT ) MG medial group of nerve ( oculomotor , nasociliary , abducens ), black arrow - lateral group of nerves (frontal, lacrimal, trochlear)

16. Parts of ALSC ( Anterior lateral sellar compartment )

17. Branches of V 1 Lateral part- from lateral to medial - LFT [ Liver functional tests ] Menumonic – Lacrimal N., Frontal N., Trochlear N . Immediately after removing the periorbita

18. 1. Lateral part- LFT [ Liver functional tests ] Menumonic – Lacrimal N., Frontal N., TrochlearN . & Superior Opthalmic Vein. 2. The frontal and trochlear nerves ascend above the Levator muscle & superior rectus muscle. Frontal N. devides into Sup.Troch.N . & Supraorb.N . – NOTE Fal.Lig

19. endoscopic endonasal viewpoint the nasal window to SOF is above V2, and below the lateral optico -carotid recess. blue-sky arrows SOF ; MS-Maxillary strut ; MP-Maxillary prominence

20. ALSC ( Anterior lateral sellar compartment) ICAc cavernous portion of the internal carotid artery, ICT inferior common tendon, IRM inferior rectus muscle, MRM medial rectus muscle, MS maxillary sinus, OA ophthalmic artery, ON optic nerve, SPR sphenopalatine region, SS sphenoid sinus, yellow arrow lateral opticocarotid recess Thicker inferior division of 3 rd N. & thinner superior division of 3 rd N

21. SOF is the space between two Structs – Superiorly OS [ Optic Strut ] & Inferiorly MS [ Maxillary Strut ]

22. The maxillary strut is identified as a really constant bony landmark useful for indicating the superior orbital fissure and the “front door” to the cavernous sinus. CS cavernous sinus , IRM inferior rectus muscle , lOCR lateral optico -carotid recess , MM Muller’s muscle , MRM medial rectus muscle , ON optic nerve , pwMS posterior wall of the maxillary sinus , VN vidian nerve , V2 second branch of the trigeminal nerve , white asterisk indicates lateral optico -carotid recess , black asterisks indicate the nasal part of the superior orbital fi ssure , black arrow indicates the division of the oculomotor nerve , red arrow indicates ophthalmic artery , yellow arrow indicates maxillary strut

23. maxillary strut blue-sky arrows SOF ; MS-Maxillary strut ; MP-Maxillary prominence

24. MS- Maxillary strut /// Average distance from the FR at PPF and the vertical segment of ICAc is 35 mm [ 3.5cm ] ( Amin et al. 2010 ) .

25. The structure Infero -lateral to SOF is – Horizontal part of carotid

26. The structure Infero -lateral to SOF is – Horizontal part of carotid

27. ALSC ( Anterior lateral sellar compartment ) ACP anterior clinoid process, ALSC anterior lateral sellar compartment, FR foramen rotundum , GWS greater wing of the sphenoid, ICAc cavernous portion of the internal carotid artery, ICT inferior common tendon, LWS lesser wing of the sphenoid, MM muscle of Muller, OA ophthalmic artery , ON optic nerve, OS optic strut, SOF superior orbital fi ssure , SS sphenoid sinus, V2 second branch of the trigeminal nerve, IIIcn oculomotor nerve, VIcn abducens nerve, black circle frontal nerve, black arrowhead nasociliary nerve

28. SOF – from middle cranial fossa approach after removal of anterior clinoid process.

29. Fig. 4.15 Microsurgical view; extradural anterior clinoidectomy . a Exposure and drilling of the anterior clinoid process and optic canal under microscope magnification. b Widened space after complete removal of the AC. AC anterior clinoid , eON extracranial intracanalar optic nerve, FD frontal dura , ICA internal carotid artery, iON intraorbital optic nerve, LWSB lesser wing of sphenoid bone, OC optic canal, OR orbit roof, SOF superior orbital fissure, TD temporal dura

30. Orbital apex

31. Parts of Orbital Apex Orbital apex is divided into the intraconal compartment extraconal compartments - passed by the lacrimal, trochlear, and frontal nerves. The frontal and trochlear nerves ascend above the Levator muscle & superior rectus muscle. Within the intraconal space, the 1. superomedial foramen - optic nerve and the ophthalmic artery pass. 2. superolateral foramen - oculomotor , nasociliary , and abducens nerves pass.

32. Parts of Orbital Apex

33. Accessing intraconal lesions endonasally requires manipulation of the extraocular muscles. The nerve branches that supply the oculomotor muscles run in the medial surface of the muscles. Thus , try to avoid excessive retraction of the extraocular muscles to avoid inadvertent muscle paresis.

34. The muller’s muscle extends for the whole length of the inferior orbital fissure , passes above the maxillary strut and enters the superior orbital fissure .

35. An important vein travelling the SOF is quite constant. It is immediately under the periorbit , outside the muscular cone, and reaches the cavernous venous compartment. This vein can be a limiting factor for drilling the SOF area ( Dallan et al. 2013 ). CS cavernous sinus , IRM inferior rectus muscle , lOCR lateral optico -carotid recess , MM Muller’s muscle , MRM medial rectus muscle , ON optic nerve , pwMS posterior wall of the maxillary sinus , VN vidian nerve , V2 second branch of the trigeminal nerve , white asterisk indicates lateral optico -carotid recess , black asterisks indicate the nasal part of the superior orbital fi ssure , black arrow indicates the division of the oculomotor nerve , red arrow indicates ophthalmic artery , yellow arrow indicates maxillary strut

36. By dividing IRM and MRM tendons it is possible to identify the 2 main branches of the oculomotor nerve, and laterally to it, the first segment of the ophthalmic artery ( Dallan et al. 2013 ).

37. By dividing IRM and MRM tendons it is possible to identify the 2 main branches of the oculomotor nerve, and laterally to it, the first segment of the ophthalmic artery ( Dallan et al. 2013 ).

38. Orbital Apex

39. FN frontal nerve, IRM inferior rectus muscle, LaN lacrimal nerve, LRM lateral rectus muscle , LWS lesser wing of the sphenoid, MRM medial rectus muscle, NCN nasociliary nerve , ON optic nerve, SRM superior rectus muscle , SS sphenoid sinus, V2 second branch of the trigeminal nerve, IIIcn oculomotor nerve , red asterisk trochlear nerve, red arrowhead abducens nerve, red circle ophthalmic artery

40. Thicker inferior division of 3 rd N. & thinner superior division of 3 rd N . 2. Nasociliary N passes between divisions of 3 rd N. 3. In the annulus, the nasociliary nerve passes medially, and it is located between the two divisions of the oculomotor nerve; the abducens nerve runs superiorly and laterally to reach the lateral rectus muscle.

41. Accessing intraconal lesions endonasally requires manipulation of the extraocular muscles. The nerve branches that supply the oculomotor muscles run in the medial surface of the muscles. Thus , try to avoid excessive retraction of the extraocular muscles to avoid inadvertent muscle paresis.

42. The pterygopalatine fossa presents an extension within the superior orbital fissure ( SOF ), inferior to the lateral sellar compartment and Muller’s muscle. It is composed of fat, small veins, and nerve fibres associated with the pterygopalatine ganglion (PPG) ( Weninger and Prahmas 2000 ) .

43. SOF , Middle Fossa , V3 in line vertically

44. GL = Gruber’s ligament

45. 1. Thicker inferior division of 3 rd N. & thinner superior division of 3 rd N . 2. Nasociliary N p asses between divisions of 3 rd N. 3. In the annulus, the nasociliary nerve passes medially, and it is located between the two divisions of the oculomotor nerve; the abducens nerve runs superiorly and laterally to reach the lateral rectus muscle.

46. A segment of the orbital portion of the optic nerve has been removed. This exposes the branch of the inferior division of the oculomotor nerve, which passes below the optic nerve and enters the medial rectus muscle.

47. When you are approaching endoscopically the upper most one is Sup.Orb.M superiorly & Medial rectus inferiorly

48. The medial approach is directed through the interval between the superior oblique and the levator muscles.

49. Lateral approach

50. Nasociliary N. [ 3 rd branch of V1 ] devides into AEN & PEN

51. Orbit from inferiorly Inferior orbital muscle is complete muscle , whereas Sup.Obl.M is muscular & tendinous Orbit from inferiorly after cutting the Inferior rectus muscle

52. Orbit from inferiorly after cutting the Inferior rectus muscle

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