10. Tracking of infraorbital nerve leads to V2 & tracking of V2 leads to Trigeminal ganglion/ Middle
cranial fossa [ one of the best way to track middle crannial fossa is to track V 2 ]
11.
12. Medial wall of PPF is perpendicular plate of palatine bone –
foramen in it is sphenopalatine foramen
13. foramen rotandum is 5 mm to middle cranial fossa dura
where as vidian nerve from vidial canal to laceral carotid is 2 cm
– listen 4.00 time in this video
https://www.youtube.com/watch?v=Uk57MEgkde8
15. The PPF extended to superior orbital fissure ( SOF ) /
Orbital apex , inferior to the cavernous sinus and
Muller’s muscle. – anterior skull base view
16. The PPF extended to superior orbital fissure ( SOF ) /
Orbital apex , inferior to the cavernous sinus and
Muller’s muscle. – Lateral skull base view
17. The PPF extended to superior orbital fissure ( SOF ) / Orbital
apex , inferior to the cavernous sinus and Muller’s muscle.
Anterior skull base Lateral skull base
18.
19. 1. One line along Vidian nerve & another line along V2
2. Lateral to LPP & infra-orbital nerve [ or V2 ] is Infratemporal fossa
3. One transverse line from Vidian nerve connecting vertical line of V 2 & another
transverse line from V2
4. The space above transverse line of Vidian nerve is Pterygoid Recess of sphenoid
5. The space above transverse line of V2 is Middle cranial fossa ( Meckel’s cave )
20. 1. Pterygoid recess [= sphenoid recess ] is pneumatisation of pterygoid
trigone – spac between V2 & VN [ Vidian nerve ]
2. The space above transverse line of Vidian nerve is Pterygoid Recess
of sphenoid
21. MPP[ medial pterygoid plate ] present at lateral surface of
posterior choana – which is in line with paraclival carotid
23. LPP if you look anteriorly (radiologically ) is in line with FR (V2) , if you look laterally posterior
border of LPP leads to V3 . So when you are removing recurrent nasopharyngeal carcinoma
transnasally you can observe LPP leads to V3 . This V3 seperates pre & post styloid
compartments.
24. Posterior genu is the most
common area of
iatrogenic injury of carotid
The parasellar carotid
protuberance is a C- shaped
bone protuberance with the
convexity of the C facing
anterolaterally. It covers four
segments of the ICA: (1) the
hidden segment / Posteriori
genu ; (2) the inferior
horizontal segment; (3) the
anterior vertical segment, and
(4) the superior horizontal
segment. The hidden segment
is located at the level of the
posterior sellar floor and
includes the posterior bend of
the ICA.
25. IATROGENIC CAROTID INJURE AREAS -
1. Upper & Lower point of C-shape of parasellar
carotid - mnemonic
2. Upper point is m-OCR ( optico - carotid recess ) -
junction of para seller & intra-cerebral carotid
3. Lower point is posterior genu - junction of
paraclival & parasellar carotid
26. Two potential iatrogenic carotid injury areas
We have to very careful at m-OCR in
transtubercular & transplanum drilling
because praclinoidal & supraclinoidal
junction is exactly m-OCR
Posterior genu is the most common
area of iatrogenic injury of carotid
27. Upper half of paraclival carotid is intracavernous while lower half is
extracavernous .
1. caudal part, the lacerum segment of the artery corresponding to the
extracavernous portion of the vessel, and
2. rostral part, the trigeminal, intracavernous portion of the artery, so- called
because the Gasserian ganglion is posterior to it and the trigeminal
divisions are lateral to it.
29. Branches of ICA – only retrograde artery is opthalmic artery
originates above the upper dural ring
30. 1. Virtual compartments of cavernous sinus – parasellar carotid virtually devides cavernous sinus into
L,M,AI,PS compartments
2. 3rd , 4th , 6th , V1 nerves in lateral compartment [ V1 & 6th nerves are in parallel ]
3. 6th nerve in antero-inferior & lateral compartments . Only 6th nerve is freely present in cavernous , that is
the reason for high chances of injury to 6th nerve in cavernous surgery .
4. 3rd nerve in postero-superior compartment
5. there is no vital [ nerves or vessesl ] in medial compartment
6. medial & postero-superior compartment are in continuity .
7. 3rd nerve & pcom are in parallel. In the same way V1 & 6th nerve are in parallel
31. Lower half of paraclival carotid - caudal part, the lacerum segment of
the paraclival carotid
”The unsolved surgical problem remains the medial wall of the ICA at the level of the
anterior foramen lacerum, until now unreachable with the available surgical
approaches." - In lateral skull base by Prof. Mario sanna – this unreachable is Carotid-
Clival window which is accessable in Anterior skull base
Infrapetrous Approach
Carotid-Clival window – Mid clivus
a. Petrosal face
b.Clival face
32. Upper half of paraclival carotid is intracavernous while lower half is
extracavernous .
1. caudal part, the lacerum segment of the artery corresponding to the
extracavernous portion of the vessel, and
2. rostral part, the trigeminal, intracavernous portion of the artery, so- called
because the Gasserian ganglion is posterior to it and the trigeminal
divisions are lateral to it.
34. Branches of ICA – only retrograde artery is opthalmic artery
originates above the upper dural ring
35. 1. Virtual compartments of cavernous sinus – parasellar carotid virtually devides cavernous sinus into
L,M,AI,PS compartments
2. 3rd , 4th , 6th , V1 nerves in lateral compartment [ V1 & 6th nerves are in parallel ]
3. 6th nerve in antero-inferior & lateral compartments . Only 6th nerve is freely present in cavernous , that is
the reason for high chances of injury to 6th nerve in cavernous surgery .
4. 3rd nerve in postero-superior compartment
5. there is no vital [ nerves or vessesl ] in medial compartment
6. medial & postero-superior compartment are in continuity .
7. 3rd nerve & pcom are in parallel. In the same way V1 & 6th nerve are in parallel
36. Lower half of paraclival carotid - caudal part, the lacerum segment of
the paraclival carotid
”The unsolved surgical problem remains the medial wall of the ICA at the level of the
anterior foramen lacerum, until now unreachable with the available surgical
approaches." - In lateral skull base by Prof. Mario sanna – this unreachable is Carotid-
Clival window which is accessable in Anterior skull base
Infrapetrous Approach
Carotid-Clival window – Mid clivus
a. Petrosal face
b.Clival face
41. 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 sellar
compartment – Located
anterior to the anterior loop
of the cavernous portion of
the internal carotid artery.
2. Orbital apex
42. Anterior lateral sellar compartment [ ALSC ]
[ SOF = ALSC + Orbital apex]
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 ).
43. Parts of ALSC ( Anterior lateral sellar
compartment )
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 ) .
44. 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. superomedial
foramen - optic nerve and
the ophthalmic artery pass.
2. superolateral
foramen - oculomotor, nasociliary,
and abducens nerves pass.
45. ORBITAL APEX [ SOF = ALSC
+ Orbital apex]
Extraconal & intraconal
compartmements
46. 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.
48. 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. superomedial
foramen - optic nerve and
the ophthalmic artery pass.
2. superolateral
foramen - oculomotor, nasociliary,
and abducens nerves pass.
49. ORBITAL APEX [ SOF = ALSC
+ Orbital apex]
Extraconal & intraconal
compartmements
50. 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]
52. 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 ]
4. 6th nerve is lateral to nasociliary nerve in between two divisions of 3rd nerve because it has
to supply lateral rectus .
54. 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 .
55. 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.
56. 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 .
58. Two potential iatrogenic carotid injury areas
We have to very careful at m-OCR in
transtubercular & transplanum drilling
because praclinoidal & supraclinoidal
junction is exactly m-OCR
Posterior genu is the most common
area of iatrogenic injury of carotid
60. classification of the ophthalmic artery types
http://www.springerimages.com/Images/MedicineAndPublicHealth/1-10.1007_s10143-006-
0028-6-1
a = intradural type,
b = extradural supra-optic strut type [ Optic strut = L-OCR ]
c = extradural trans-optic strut type
61. Type b = extradural supra-optic strut
type [ Optic strut = L-OCR
62. In Type c = extradural trans-optic strut type , the Opthalmic
foramen in Optic strut
63. classification of the ophthalmic artery types
http://www.springerimages.com/Images/MedicineAndPublicHealth/1-
10.1007_s10143-006-0028-6-1
a = intradural type,
b = extradural supra-optic strut type [ Optic strut = L-OCR ]
c = extradural trans-optic strut type
on optic nerve, pr proximal ring, cdr carotid dural
ring= upper dural ring , ica internal carotid artery
I think this variation is type c
64. In both type a = intradural type,
b = extradural supra-optic strut types Opthalmic
foramen is in Optic canal
65. In Type c = extradural trans-optic strut type , the Opthalmic
foramen in Optic strut
68. Both sides 6th nerves in dorello’s canals present medial to
para-clival carotids in mid-clivus & crosses Para-clival & Para-
sellar carotids juction in cavernous sinus
69. 1. Both sides 6th nerves in dorello’s canals present medial to para-clival carotids in mid-clivus &
2. 6th nerve crosses Para-clival & Para-sellar carotids juction in AI [ antero-inferior ] virtual
compartment of cavernous sinus
70. 1. MPP & ET opening is
in line with paraclival
carotid .
2. Laceral carotid is in
posterior wall of
pterygoid recess /
sphenoid recess.
3. Transpyerygoid
approach is needed to
reach parasellar area.
4. Area between LPP &
MPP extrapolated lines is
cavernous sinus .
5. LPP in line with FR
6. Traiangle between FR
& VC is pterygoid trigone
or Pterygoid recess /
sphenoid recess
71. 1. SHA supplies anterior pituitary originates from first part of intracerebral carotid
2. IHA supplies posterior pituitary , branch of MHT originates from posterior genu of carotid
3. ILT arises from horizontal carotid in parkinsons triangle
4. Strong opponents of extracapsular dissection of pituitary surgery argument is IHA is
damaged sothat posterior pituitary compromised & diabetes insipidus develops .
