SOF 360°24-5-2017

2.27pm

Great teachers – All this is their work . I am just the reader of their books .

Prof. Paolo castelnuovo

Prof. Aldo Stamm Prof. Mario Sanna

Prof. Magnan

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Inferior to L-OCR is Superior Orbital Fissure

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

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

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

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

SOF - Anterior

SOF - Posterior

Anterior wall of Cavernous sinus , SOF , Orbital apex in continnum

[ SOF = ALSC + Orbital apex]

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 [ SOF = ALSC + Orbital apex]

1. ALSC = Anterior lateral sellarcompartment – Located anterior to the anterior loop of the cavernous portion of the internal carotid artery.

2. Orbital apex

Anterior lateral sellar compartment [ ALSC ][ SOF = ALSC + Orbital apex]

Parts of ALSC ( Anterior lateral sellarcompartment )

1. Superior Part – Nervous compartment

a. Lateral Group of nerves - from lateral to medial - LFT[ Liver functional tests ] Menumonic – Lacrimal N., Frontal N.,TrochlearN.

b. Middle Group of nerves - 3rd , 6th , Nasocilliary N.

2. 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 ) .

ORBITAL APEX [ SOF = ALSC + Orbital apex]

Orbital apex is divided into the

1. intraconal compartment

2. 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. superomedialforamen - optic nerve and the ophthalmic artery pass.

2. superolateralforamen - oculomotor, nasociliary, and abducens nerves pass.

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.

Anterior wall of Cavernous sinus , SOF , Orbital apex in continnum

[ SOF = ALSC + Orbital apex]

ORBITAL APEX [ SOF = ALSC + Orbital apex]

Orbital apex is divided into the

1. intraconal compartment

2. 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. superomedialforamen - optic nerve and the ophthalmic artery pass.

2. superolateralforamen - oculomotor, nasociliary, and abducens nerves pass.

1. 3rd nerve supplies to the muscles from medially – so when you are doing principle of divergence [ to separate the ocular muscles ] to remove the intraconal tumors , don’t stretch

too much , chances of nerve avulsion from the muscle is there sothat muscle palsy 2. SO4 LR6 – all muscles by 3rd nerve , super oblique by 4th nerve , lateral rectus by 6th nerve 3. MG = medial group of nerves – 3rd, 6rth , nasociliary ; LG = lateral group of nerves – LFT [

mneumonic = Lacrimal , frontal , trochlear ]

Orbital apex

[ SOF = ALSC + Orbital apex]

Lateral sellar compartment ( = Cavernous sinus )

Lateral sellar compartment ( = Cavernous sinus )

ALSC ( Anterior lateral sellarcompartment )

Parts of ALSC ( Anterior lateral sellarcompartment )

1. Superior Part – Nervous compartment

a. Lateral Group of nerves - from lateral to medial - LFT[ Liver functional tests ] Menumonic – Lacrimal N., Frontal N.,TrochlearN.

b. Middle Group of nerves - 3rd , 6th , Nasocilliary N.

2. 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 ) .

Anterior lateral sellar compartment [ ALSC ][ SOF = ALSC + Orbital apex]

1. 3rd nerve supplies to the muscles from medially – so when you are doing principle of divergence [ to separate the ocular muscles ] to remove the intraconal tumors , don’t stretch

too much , chances of nerve avulsion from the muscle is there sothat muscle palsy 2. SO4 LR6 – all muscles by 3rd nerve , super oblique by 4th nerve , lateral rectus by 6th nerve 3. MG = medial group of nerves – 3rd, 6rth , nasociliary ; LG = lateral group of nerves – LFT [

mneumonic = Lacrimal , frontal , trochlear ]

Orbital apex

[ SOF = ALSC + Orbital apex]

Red rings = thicker lower division , thinner upper division ; Green ring = 6th nerve ; Yellow ring = Nasociliary nerve

Mneumonic = My left hand middle finger is thicker than left hand index finger , so Lower division of 3rd nerve is thicker than upper division of 3rd nerve .

Nasociliary nerve present between two divisions of 3rd nerve & 6th nerve present lateral to nasociliary nerve

1. In SOF [ superior orbital fissure ] & Orbital apex in nasal endosopic view - 3rd nerve devides into thicker lower division & thinner upper division – in between these two

divisions 6th nerve & nasociliary nerve is seen .2. 6th nerve is lateral to nasociliary nerve in between two divisions of 3rd nerve

because it has to supply lateral rectus .

Orbital apex [ SOF = ALSC + Orbital apex]

1. SOF present between two structs2. OS [ optic struct separates optic canal from SOF ]

1. SOF present between two structs2. OS [ optic struct separates optic canal from SOF ]

Anterior wall of Cavernous sinus , SOF , Orbital apex in continnum

[ SOF = ALSC + Orbital apex]

Nasal part of SOF

SOF & IOF are in C-shape when you see through orbit /maxilla/nose

SOF & IOF are in C-shape when you see through orbit /maxilla/nose

Anterior lateral sellar compartment

1. 3rd nerve supplies to the muscles from medially – so when you are doing principle of divergence [ to separate the ocular muscles ] to remove the intraconal tumors , don’t stretch

too much , chances of nerve avulsion from the muscle is there sothat muscle palsy 2. SO4 LR6 – all muscles by 3rd nerve , super oblique by 4th nerve , lateral rectus by 6th nerve 3. MG = medial group of nerves – 3rd, 6rth , nasociliary ; LG = lateral group of nerves – LFT [

mneumonic = Lacrimal , frontal , trochlear ]

Orbital apex

Levator palpebrae superioris originates from lesser wing of sphenoid

1. 6th nerve crosses para-clival & para-sellar carotid junction in the dorellos canal 2. in SOF 4TH nerve is above the 3rd nerve where as in cavernous sinus 3rd nerve above 4th nerve

3. supratrochlear & infratrochlear triangle above & below the 4th nerve .

1. In SOF [ superior orbital fissure ] & Orbital apex in nasal endosopic view - 3rd nerve devides into thicker lower division & thinner upper division – in between these two

divisions 6th nerve & nasociliary nerve is seen .2. 6th nerve is lateral to nasociliary nerve in between two divisions of 3rd nerve

because it has to supply lateral rectus .

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.

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)

Parts of ALSC ( Anterior lateral sellarcompartment )

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

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

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

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 3rd N. & thinner superior division of 3rd N

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

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 divisionof the oculomotor nerve, red arrow indicates ophthalmic artery, yellow arrow indicates maxillary strut

maxillary strut

blue-sky arrows SOF ; MS-Maxillary strut ; MP-Maxillary prominence

MS- Maxillary strut /// Averagedistance from the FR at PPF and the vertical segment of ICAc is

35 mm [ 3.5cm ] (Amin et al. 2010 ) .

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

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

ALSC ( Anterior lateral sellarcompartment )

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 oculomotornerve, VIcn abducens nerve, black circle frontal nerve, black arrowhead nasociliary nerve

Coronal histological sections through the superior orbital ssure of a newborn head. A Section through the commonannular tendon. Inferior tendon forms a concave gutter for the oculomotor (III), nasociliary, and abducens (VI) nerves.

B Tendinous bers of the lateral rectus (LR) and superior rectus muscles join to close the superolateral foramen (arrowhead).Inferior rectus muscle (IR), medial rectus muscle (MR) (with permission from Institute of Anatomy of Strasbourg)

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

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

Clinoid has three roots of attachment 1. Anteriror root = Anterior Clinoid process attachemnt to planum

2. Posterior root = Optic struct = L-OCR 3. 3rd root = Anterior Clinoid process attachment to Lesser wing of sphenoid

Three surgical attachments of the right anterior clinoid process. (a, sphenoid ridge; b, roof of optic canal; c, optic strut.)

Anterior clinoid drilling videos in FTOZ [ neurosurgery skull base ]

1. https://www.youtube.com/watch?v=wO2cWHiOdO0

2. https://www.youtube.com/watch?v=4dkQY3zxJHU

3. https://www.youtube.com/watch?v=vd4_lPVIUvE

4. https://www.youtube.com/watch?v=_dvYB1InGMc

5. https://www.youtube.com/watch?v=83_VuKHXOmQ

6. https://www.youtube.com/watch?v=0KwBhTqNXA4

7. https://www.youtube.com/watch?v=pCURjQ83HzU

8. https://www.youtube.com/watch?v=DNIy0L3oFgY

9. https://www.youtube.com/watch?v=GT4eBB2x58Q

10. https://www.youtube.com/watch?v=OS4Mc0X8tlU

11. https://www.youtube.com/watch?v=_xq9e3p1cc4

Orbital apex

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.

Anterior wall of Cavernous sinus , SOF , Orbital apex in continnum

[ SOF = ALSC + Orbital apex]

ORBITAL APEX [ SOF = ALSC + Orbital apex]

Orbital apex is divided into the

1. intraconal compartment

2. 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. superomedialforamen - optic nerve and the ophthalmic artery pass.

2. superolateralforamen - oculomotor, nasociliary, and abducens nerves pass.

Parts of Orbital Apex

Accessing intraconal lesions endonasally requires manipulation of the extraocularmuscles. The nerve branches that supply the oculomotor muscles run in the medial

surface of the muscles. Thus, try to avoid excessive retraction of the extraocularmuscles to avoid inadvertent muscle paresis.

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.

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

Nasal part of SOF

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 ).

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 ).

Cadaveric dissection demonstrating the anatomy of the right orbital apex following removal of the lamina papyracea, periorbita, and orbital fat. (OA, ophthalmic artery;

MR, medial rectus; ON, optic nerve; IR, inferior rectus; MM, Muller muscle; V2, second branch of the trigeminal nerve.)

Orbital Apex

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

1. Thicker inferior division of 3rd N. & thinner superior division of 3rd N . 2. Nasociliary N passes between divisions of 3rd 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.

1. In the posterior part of the CS the trochlear nerve is below the oculomotor nerve, while anteriorly it turns upward and becomes the most superior structure of the CS (at the level of

the optic strut) (Iaconetta et al. 2012 ) .

2. Trochlear nerve is always superior to V1.

1. 6th nerve crosses para-clival & para-sellar carotid junction in the dorellos canal 2. in SOF 4TH nerve is above the 3rd nerve where as in cavernous sinus 3rd nerve above 4th nerve

3. supratrochlear & infratrochlear triangle above & below the 4th nerve .

In SOF [ superior orbital fissure ] & Orbital apex in nasal endosopic view - 3rd

nerve devides into thicker lower division & thinner upper division – in between these two divisions 6th nerve & nasociliary nerve is seen .

Accessing intraconal lesions endonasally requires manipulation of the extraocularmuscles. The nerve branches that supply the oculomotor muscles run in the medial

surface of the muscles. Thus, try to avoid excessive retraction of the extraocularmuscles to avoid inadvertent muscle paresis.

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 ) .

SOF , Middle Fossa , V3 in line vertically

GL = Gruber’s ligament

1. Thicker inferior division of 3rd N. & thinner superior division of 3rd N . 2. Nasociliary N passes between divisions of 3rd 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.

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.

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

inferiorly

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

Lateral approach

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

Orbit from inferiorlyInferior orbital muscle is complete muscle , whereas Sup.Obl.M is muscular & tendinous

Orbit from inferiorly after cutting the Inferior rectus muscle

Orbit from inferiorly after cutting the Inferior rectus muscle

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