1. Cavernous Sinus 360°
29-9-2016
8.12 pm

2. 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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“ Skull base 360° ”
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4. TEPS [ Trans-ethmoid pterygoid sphenoid ] approach to
cavernous sinus

5. Lateral sellar compartment ( =
Cavernous sinus )

6. Safe location for opening the meckels cave – inferior to
V2 , lateral to paraclival carotid because it is far inferior
to 6th nerve – find safe location to open the cavernous
sinus

7. Front door

8. 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

9. To know SOF [ Superior Orbital Fissure ] click
http://www.slideshare.net/muralichandnallamothu/superior-
orbital-fissure-360
Yellow line = “nasal” part of SOF
Clinically, the SOF and CS apex
represents a continuum.

10. Roof

11. Roof - two triangles:
1. clinoid (anterior)
2. oculomotor (posterior)
ACP anterior clinoid process, APCF anterior petroclinoid fold, DS dorsum sellae, ICF interclinoid
fold, PF pituitary fossa, PLL petrolingual ligament (inferior sphenopetrosal ligament),
PPCF posterior petroclinoid fold, PS planum sphenoidale, SSPL superior sphenopetrosal
ligament (Gruber’s ligament), TS tuberculum sellae, black asterisk middle clinoid process , CSR
cavernous sinus roof , white asterisk oculomotor nerve
If the Gruber’s ligament is ossificated it is called Wegener’s
bridge.

12. Interclinoidal ligament/fold [ ICF ] after
pituitary extracapsular extraction

13. Roof - two triangles:
1. clinoid (anterior)
2. oculomotor (posterior)
Anterior skull base approach – see
clinoid triangle in below photo

14. Occulomotor triangle – courtesy by Dr.
Sukhdeep Jhawar

15. The lower dural ring is given by the COM, that lines the inferior surface of the ACP. It
can be visible, through a transcranial route, only by removing the ACP. The lower dural
ring is also called Perneczky’s ring. Medially the COM blends with the dura that lines
the carotid sulcus (Yasuda et al. 2005 )
Endoscopic supraorbital view of the anterior clinoid region. The right
portion of the planum sphenoidale is seen from above. The anterior clinoid process
has been removed. Vision obtained through a right supraorbital approach with a 30°
down-facing lens focusing on the cavernous sinus roof.
ACP anterior clinoid process (removed), COM carotid oculomotor membrane, ICAc
cavernous portion of the internal carotid artery, ICAi intracranial portion of the
internal carotid artery, OA ophthalmic artery, ON optic nerve, LWS lesser wing of the
sphenoid, IIIcn oculomotor nerve

16. The lower dural ring is given by the COM [ Carotid-oculomotor
membrane ] , that lines the inferior surface of the ACP. It can be visible, through a
transcranial route, only by removing the ACP. The lower dural ring is also called
Perneczky’s ring. Medially the COM blends with the dura that lines the carotid sulcus
(Yasuda et al. 2005 )
Endoscopic supraorbital view with a 30°
down-facing lens -The right portion of the
planum sphenoidale is seen from above.
Right side

17. COM = carotico–oculomotor
membrane
Superior view of the right
ophthalmic artery in the right paraclinoid area. The anterior
clinoid process, which is situated on the lateral side of the
optic nerve, has been removed. The optic canal has been
unroofed, the optic sheath opened, and the optic nerve elevated
to expose the origin of the ophthalmic artery under the
medial half of the optic nerve. In the optic canal, the ophthalmic
artery courses within the dural sheath of the optic
nerve. It exits the optic canal and the optic sheath to enter the
orbital apex on the inferolateral aspect of the optic nerve.
The oculomotor nerve courses just below the dura covering
the lower margin of the anterior clinoid process. The clinoid
segment of the internal carotid artery is the segment that
courses on the medial side of the anterior clinoid process and
is exposed by removing the anterior clinoid process. The
upper edge of the clinoid segment is defined by a dural ring,
called the upper dural ring, formed by the dura, which
extends medially from the upper surface of the anterior clinoid
process. The lower edge of the clinoid segment is
defined by the lower dural ring, which is formed by the dura
that line1 the lower surface of the anterior clinoid process and
separates the clinoid process from the upper surface of the
oculomotor nerve and continues medially as the carotid-
oculomotor membrane to surround the carotid artery The
ophthalmic
artery usually arises just above the clinoid segmenl
However, it may infrequently arise from the clinoid segment.

18. Anatomically speaking, the paraclinoid segment of the internal carotid artery is not fully
intracavernous, and it is separated from the cavernous sinus by the extension of the dura
covering the inferior surface of the anterior clinoid process (Reisch et al. 2002 ) .
Note carotid cave , cavernous
sinus , upper & lower dural rings

19. Aneurysms of initial intracranial
carotid

20. Fig. 22.31 Clinoidal and oculomotor triangles
have been opened and the anterior clinoid removed
up to the optic strut, exposing the carotido-
oculomotor membrane. The optic strut has two
neural-facing surfaces( yellow dotted lines) and one
vascular-facing surface (red dotted line). CN: cranial
nerve; Falc.: falciform; ICA: internal carotid artery;
Inf.:inferior; Lig.: ligament; Pet.: petrosal; V1: first
division; V2: second division; V3: third division of
trigeminal nerve.
ACP anterior clinoid process, APCF anterior
petroclinoid fold, DS dorsum sellae, ICF
interclinoid fold, PF pituitary fossa, PLL
petrolingual ligament (inferior sphenopetrosal
ligament), PPCF posterior petroclinoid fold, PS
planum sphenoidale, SSPL superior
sphenopetrosal ligament (Gruber’s ligament), TS
tuberculum sellae, black asterisk middle clinoid
process

21. See the Gasserian ( V , VI ) emerge through the posterior petroclinoidal ligament , ( III ,
IV ) through triangle between the anterior petroclinoidal and interclinoidal ligament
next show how the both interclinoidal ligament give sleeves of upper and lower dural
rings these ligaments with attachment to petrous edge and clinoid processes( anterior
and posterior ) , stabilizing and held the cranial nerves and carotid , reinforcing the
dural wall of sinuses

22. Rahul Kumar The ILT is an important vessel in this region, vascularising many of the
tumours and fistulas, as well as cranial nerves. It can be seen hooking around the sixth
nerve in the panel on the right. It has rich anastomoses with many branches from the
external carotid

23. Roof

24. Oculomotor cistern
Cranial nerve III enters the roof included in its own cistern
(oculomotor cistern).
Oculomotor cistern goes upto
anterior clinoid tip

25. The optic strut has two neural-
facing surfaces( yellow dotted
lines) and one vascular-facing
surface (red dotted line).
[ COM= Lower dural ring – Carotico-
Occulomotor membrane seperates
3rd N from Clinoidal carotid ]

26. Medial wall

27. yellow arrow inferior part ( Sphenoidal part ) of the medial wall of the cavernous sinus (
yellow line ), blue-sky arrow superior ( Sellar part ) of the medial wall of the cavernous
sinus ( blue-sky line )
In the upper part, the medial wall is given by the meningeal layer, that is a continuation of the
diaphragma sellae, which surrounds the pituitary capsule inferiorly (Yasuda et al. 2005 ; Martins
et al. 2011 ) . In the inferior part, the medial wall is given by the endosteal layer that covers the
body of the sphenoid bone.

29. The medial and lateral walls join inferiorly in a ‘keel- like’
formation at the level of the superior margin of the maxillary
nerve.

30. Lateral wall

31. In FTOZ APPROACH - From Surgical anatomy of the petrous apex and petroclival region book -
H.-D. FOURNIER2, P. MERCIER2, and P.-H. ROCHE1
Fig. 23. Exposure of the epidural temporopolar space (Head cadaver dissection, right
side): the meningoorbital band is the thick fibrous band that connect the periorbital
fascia to the temporopolar dura. At the right bottom corner, the same view is shown in
an operative case

32. From book Analomy and Surgery of the Cavernous Sinus - Vinko V. Dolene old book
Fig. 15. In the anterior area of the anterolateral triangle a huge vein enters the lateral
wall of the CS. The intense blue color of the lateral wall of the CS indicates that there
is abundant blood between its layers

33. From book Analomy and Surgery of the Cavernous Sinus - Vinko V. Dolene old book
Fig. 63. Further removal of the outer layer of the lateral wall of the CS from the vein
entering the CS shows a huge collection of »venous blood« between the two layers of
the lateral wall of the CS. The venous injection is also seen in the paramedial triangle
and laterally in the lateral triangle

34. http://www.slideshare.net/INUB/endoscopic-anatomy-and-approaches-of-the-cavernous-sinus-
cadaver-study - Endoscopic view of the right cavernous sinus and neurovascular relations,
demonstrating the ‘S’ shaped configuration formed by the oculomotor, the
abducens , carotid nerve ( paraclival carotid ) and the vidian nerves.
III oculomotor nerve, V1 ophthalmic nerve, V2 maxillary nerve, V3 mandibular nerve, VI abducens
nerve, C clivus, ICA-Sa anterior bend of the internal carotid artery–parasellar segment, ICA-Sp posterior
bend of the internal carotid artery–parasellar segment, ICA-C paraclival segment of the internal carotid
artery, ICA-L lacerum segment of the internal carotid artery, ICA-P petrous segment of the internal
carotid artery, PG pituitary gland, VC vidian canal, VN vidian nerve
VI nerve is parallel & medial to V1 –
in the same direction of V1 [
Mneumonic – VI & V1 in same
direction ]

35. Meningo-hypophyseal trunk & carotid nerve

36. 1. 6th N. crossing carotid at Petro-clival junction when viewing in lateral skull base - The
lateral aspect of the parasellar & paraclival carotid junction is crossed by the
abducent nerve (VI) at the entrance of both [ 6th nerve & carotid ] structures into the
cavernous sinus.
2. The gulfar segment can be identified at the intersection of the sellar floor and the
proximal parasellar internal carotid artery (ICA) (Barges-Coll et al. 2010 ).

37. 1. 6th N. crossing carotid at Petro-clival junction when viewing in lateral skull
base - The lateral aspect of the parasellar & paraclival carotid junction is
crossed by the abducent nerve (VI) at the entrance of both [ 6th nerve &
carotid ] structures into the cavernous sinus.
2. The gulfar segment can be identified at the intersection of the sellar floor
and the proximal parasellar internal carotid artery (ICA) (Barges-Coll et al.
2010 ).

38. Carotid nerve –
part of S’ shaped configuration formed by the
oculomotor, the abducens , carotid nerve (
paraclival carotid ) and the vidian nerves.

39. VI nerve is parallel & medial to V1 – in the same direction of V1 [ Mneumonic – VI &
V1 in same direction ]

40. STA is devided into 1. Supra-Trochlear triangle
2. Infra-Trochlear triangle

41. STA is devided into 1. Supra-Trochlear triangle
2. Infra-Trochlear triangle
1.Supra Trochanteric & Infratrochanteric Triangles
2. Upper & lower dural rings
3. lower dural ring is COM ( Carotico-Oculomotor Membrane )
In the below picture superior
cerebellar artery mislabelled as
meningohypophyseal trunk .

42. STA is devided into 1. Supra-Trochlear triangle
2. Infra-Trochlear triangle
1.Supra Trochanteric & Infratrochanteric Triangles
2. Upper & lower dural rings
3. lower dural ring is COM ( Carotico-Oculomotor Membrane )
Right lateral view of the inferolateral trunk or artery of the inferior
cavernous sinus, a branch of the horizontal part of the internal carotid
artery (ICA) that provides blood to the dura of the lateral wall of the
cavernous sinus as well as to the cranial nerves running along the lateral
wall of the cavernous sinus. The trochlear nerve has been displaced
inferiorly and the oculomotor nerve has been displaced superiorly. A
recurrent branch from the inferolateral trunk is observed in this specimen.
This branch heads back toward the tentorium cerebelli forming the so-
called marginal tentorial artery. 1=horizontal segment of cavernous ICA,
2=clinoid segment of ICA, 3=supraclinoid ICA, 4=inferolateral trunk or
artery of the inferior cavernous sinus, 5=marginal tentorial artery, 6=optic
nerve, 7=oculomotor nerve, 8=trochlear nerve, 9=ophthalmic nerve,
10=abducent nerve, and 11=sphenoid sinus.

43. http://posterng.netkey.at/esr/viewing/index.php?module=viewing_poster&task=view
section&pi=122476&ti=402607&si=1380&searchkey=#poster
Fig. 1: Schematic drawing of the inferolateral trunk (ILT). The ILT arises from lateral
surface of the C4 segment of the internal carotid artery. The ILT gives rise to three
branches: tentorial branch, anterior branch, and posterior branch. The anterior branch
divides into the anteromedial branch and anterolateral branch. The posterior branch
divides into posteromedial branch and posterolateral branch. ; AB, anterior branch;
ALB, anterolateral branch; AMB, anteromedial branch; ICA, internal carotid artery; ILT,
inferolateral trunk; OpA, ophthalmic artery; PB, posterior branch; PLB, posterolateral
branch; PLB,posterolateral branch; TB, tentorial branch References: Radiology, Oita
University - Yufu city/JP

44. 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.

46. From lateral skull base - The lateral aspect of the parasellar &
paraclival carotid junction is crossed by the abducent nerve (VI)

47. The abducens nerve in most case is a single trunk throughout its entire course (Zhang et al. 2012 ) . There
are some variants, and one should be aware that the nerve can fuse with the oculomotor nerve for all its
course (Zhang et al. 2012 ) . The surgeon must be prepared to face other rare variations, such as different
fasciculi within the CS. Globally, the incidence of a duplicated abducens nerve has been reported, ranging
from 8 % to 18 % (Nathan et al. 1974 ; Iaconetta et al. 2001 ; Ozveren et al. 2003 ) . In the prepontine cistern,
when the duplication is present, AICA passes through the bundles. Furthermore, the incidence of a
bilaterally duplicated nerve has been reported as frequently as 8 % of the time (Nathan et al. 1974 ; Ozveren
et al. 2003 ) . The abducens nerve can pass above the Gruber’s ligament in 12 % of cases (Lang 1995 ) .
Endoscopic vision of the cavernous sinus. Vision obtained through a right supraorbital
approach with a 30° down-facing lens focusing on the cavernous sinus
ICAc cavernous portion of the internal carotid artery, lwCS lateral wall of the cavernous sinus, SCA
superior cerebellar artery, IIIcn oculomotor nerve, IVcn trochlear nerve, Vcn root of the trigeminal nerve,
VIcn abducens nerve, blue arrow Gruber’s ligament, white asterisk Dorello’s canal.

48. Blue arrow in Left picture ; * in Right
picture - Gruber’s ligament

49. http://www.slideshare.net/INUB/endoscopic-anatomy-and-approaches-of-the-
cavernous-sinus-cadaver-study- Endoscopic view of the right cavernous sinus and its
neurovascular relations, demonstrating the triangular area formed by the medial
pterygoid process laterally, the parasellar ICA medially and the vidian nerve inferiorly
at the base. III oculomotor nerve, V1 ophthalmic nerve, V2 maxillary nerve, V3
mandibular nerve, VI abducens nerve, C clivus, ICA-Sa anterior bend of the internal
carotid artery–parasellar segment, ICA-Sp posterior bend of the internal carotid
artery–parasellar segment, ICA-C paraclival segment of the internal carotid artery, ICA-
L lacerum segment of the internal carotid artery, ICA-P petrous segment of the
internal carotid artery, PG pituitary gland, VC vidian canal, VN vidian nerve

50. http://www.slideshare.net/INUB/endoscopic-anatomy-and-approaches-of-the-cavernous-
sinus-cadaver-study -Endoscopic view of the right cavernous sinus showing its neurovascular
relations and the main anatomic areas. III oculomotor nerve, V1 ophthalmic nerve, V2
maxillary nerve, V3 mandibular nerve, VI abducens nerve, C clivus, ICA-Sa anterior bend of
the internal carotid artery–parasellar segment, ICA Sp posterior bend of the internal carotid
artery–parasellar segment, ICA-C paraclival segment of the internal carotid artery, ICA-L
lacerum segment of the internal carotid artery, ICA-P petrous segment of the internal carotid
artery, PG pituitary gland, VC vidian canal, VN vidian nerve, STA superior triangular area, SQA
superior quadrangular area, IQA inferior quadrangular area
1.Supra Trochanteric & Infratrochanteric Triangles
2. Upper & lower dural rings

51. C2 , C3 , C4 – QS is wrongly mentioned here . QS in
below photo is actually antero-medial triangle

52. QS = Quadrangular space

53. Quadrangular space

54. http://www.slideshare.net/INUB/endoscopic-anatomy-and-approaches-of-the-
cavernous-sinus-cadaver-study - Endoscopic view (a), and a drawing (b) of the right
cavernous sinus demonstrating its neurovascular relations. c A drawing of the right
cavernous sinus demonstrating the exposure of the trochlear nerve after retracting
the oculomotor nerve. III oculomotor nerve, IV trochlear nerve, V1 ophthalmic nerve,
VI abducens nerve, ICA internal carotid artery, OA ophthalmic artery, OCh optic
chiasm, ON optic nerve, PG pituitary gland

55. L-OCR – Triangle
1. Upper boarder – Optic nerve & Opthalmic artery
2. Posterior boarder – Clinoidal carotid
3. Lower boarder – 3rd N. [ COM – Carotico-Occulomotor
membrane seperates 3rd N from Clinoidal carotid ]
[ 6th N. & 4th N. & V1 present inferior to 3rd N. ]

56. Cutting the maxillary nerve to gain access to the lateral wall
of the cavernous sinus in infratemporal fossa approach type C – ITFA-C
Cutting the maxillary nerve to
gain access to the lateral wall
of the cavernous sinus.
The abducent nerve (VI) crosses from
the medial to the lateral aspect of the
internal carotid artery (ICA) before
entering the
cavernous sinus.

57. V2 also included in the cavernous sinus
or not – find

58. CS virtual compartments

59. CS divided into four virtual compartments:
1. medial,
2. lateral,
3. posterosuperior, and
4. anteroinferior
Right cavernous sinus dissection. The quadrilateral delimits the right cavernous sinus area.
a Before periosteal layer removal. b After periosteal layer removal. c Cavernous sinus
compartments.
L = Lateral; AI = antero- inferior; PS = posterosuperior compartment of the cavernous sinus (the
medial is a virtual space in continuity with the AI and PS).
Medial and posterosuperior compartments are in strict continuity and do not contain nerves,
representing a surgical corridor without risk of neural damage. The anteroinferior and lateral
compartments contain the abducens nerve and, as surgical corridors, they are exposed to the risk
of injury to the VIth nerve.

60. Medial compartment

61. Medial compartment
- By opening the dura of the medial wall of the cavernous sinus, the
space between the internal carotid artery and the PG is exposed. In
this space, the MHT is usually evident.
BCA Bernasconi-Cassinari artery, CF cavernous fat, CR clival recess, DMA dorsal meningeal
artery, GR gyrus rectus, ICAc cavernous portion of the internal carotid artery, IHA inferior
hypophyseal artery, MHT meningohypophyseal trunk,PG pituitary gland

62. DMA dorsal meningeal artery, ICAc cavernous portion of internal carotid artery, IHA inferior
hypophyseal artery, MHT meningohypophyseal trunk, PCFd dura and periosteum of the
posterior cranial fossa, PG pituitary gland, VIcn abducens nerve
The MHT is traditionally described as having three branches: the inferior hypophyseal artery, the
dorsal meningeal artery (also called the dorsal clival artery), and the tentorial artery (also called the
Bernasconi-Cassinari artery). The DMA is in close relationship with the abducens nerve at the level
of petrous apex (Cavallo et al. 2011 ) . The DMA is the main feeder of the Dorello’s segment of VIcn
(Martins et al. 2011 ) .

63. ?McConnell’s artery [ Rhoton 2002] / MHT

64. ACP anterior clinoid process, BCA Bernasconi-Cassinari artery, DMA dorsal meningeal artery, DS dorsum sellae, FO
foramen ovale, FR foramen rotundum, ICAc cavernous portion of the internal carotid artery, ICAh horizontal portion of
the internal carotid artery, IHA inferior hypophyseal artery, MHT meningohypophyseal trunk, OA ophthalmic artery, PS
planum sphenoiodale, TS tuberculum sellae, white arrow MHT, red asterisk lingula of the sphenoid
The MHT is present in most cases. Not in all cases does it give off all the typical braches: dorsal meningeal artery (or
dorsal clival artery), tentorial artery (or Bernasconi-Cassinari artery), and the inferior hypophyseal arteries. In about half
of the cases, some branches arise directly from the ICAc (Jittapiromsak et al. 2010 ) . The tentorial artery is the main
feeder of the oculomotor nerve (d’Avella et al. 2008 ) , and usually it is located on the inferior surface of the nerve.
Moreover, it can be the feeder of the distal part of the trochlear nerve; in these cases, the vessel runs in close proximity
of this nerve to the superior orbital fi ssure. Other authors show that BCA feeds cranial nerve IV along its course within
the tentorium cerebelli (Martins et al. 2011 ) .

65. Posterosuperior compartment

66. Posterosuperior compartment –
Oculomotor triangle is seen – 3rd N. , 4th N. & Pcom
seen.

67. Cadaveric dissection image demonstrating the close anatomical relationship
of the posterior clinoid (PC) with both the intracranial carotid artery (ICCA)
and the posterior genu of the intracavernous carotid artery (P. CCA). AL,
anterior lobe of the pituitary gland; PL, posterior lobe of the pituitary gland;
BA, basilar artery.

68. Antero-inferior compartment

69. Antero-inferior compartment
1. The abducens nerve and the sympathetic plexus around the intracavernous carotid artery are
the only nerves which have a real intracavernous course.
2. The anteroinferior and lateral compartments contain the abducens nerve and, as surgical
corridors, they are exposed to the risk of injury to the VIth nerve.
BS basisphenoid, CS cavernous sinus, CSd dura of the cavernous sinus, ET eustachian tube, ICAc cavernous portion of the internal carotid
artery, ICAh horizontal portion of the internal carotid artery, ICAp parapharyngeal portion of the internal carotid artery, ILT inferolateral
trunk, LVPM levator veli palatini muscle, MHT meningohypophyseal trunk, PAp petrous apex, PCFd posterior cranial fossa dura and
periosteum, PG pituitary gland, TVPM tensor veli palatini muscle, VN vidian nerve, IIIcn oculomotor nerve, IVcn trochlear nerve, V1 fi rst
branch of the trigeminal nerve, V2 second branch of the trigeminal nerve, V3 third branch of the trigeminal nerve, VIcn abducens nerve,
XIIcn hypoglossal nerve, white asterisks sympathetic fi bres
connecting the VIcn

70. In rare situation we have to anticipate OA in Antero-inferior & Lateral
compartments of CS . Opthalmic artery – Retrograde branch of
Intracranial carotid
Branches of the cavernous internal
carotid artery ( ICA ), a rare
variation: ophthalmic
artery passing through the superior
orbital fissure
Normal OA above upper dural
ring

71. Between VN & V2
• 1. lateral recess of sphenoid
• 2. petrous apex

72. VI nerve is parallel & medial to V1 – in the same
direction of V1 [ Mneumonic – VI & V1 in same
direction ]

73. Lateral compartment

74. Lateral compartment
ACP anterior clinoid process, ChS chiasmatic sulcus, DS dorsum sellae, FO foramen ovale, ICAc cavernous
portion of the internal carotid artery, ICAh horizontal portion of the internal carotid artery, ILT inferolateral
trunk, MHT meningohypophyseal trunk, OS optic strut, PCP posterior clinoid process, PF pituitary fossa, PG
pituitary gland, TS tuberculum sellae, VIcn abducens nerve, white arrow s branches of the ILT
The ILT is present in most cases (Krisht et al. 1994 ; Tran-Dinh 1987 ) . It may arise as a common trunk with the
MHT (Reisch et al. 2002 ) . It is a single trunk in most cases. More often, it arises from the lateral aspect of the
horizontal segment of the ICAc, and in most cases it passes superiorly to the abducens nerve (Inoue et al. 1990
; Jittapiromsak et al. 2010 ) . It usually gives rise to 3 or 4 branches supplying the dura and the cranial nerves
within the cavernous sinus (Lasjaunias et al. 1977 ; Tran - Dinh 1987 ) . The main trunk of the ILT with small
secondary branches is the feeder of the ophthalmic nerve (V1). Usually, these vessels reach the inferior surface
of the nerve. Obviously, the ILT also supplies the abducens nerve with several small branches.

75. In rare situation we have to anticipate OA in Antero-inferior & Lateral
compartments of CS . Opthalmic artery – Retrograde branch of
Intracranial carotid
Branches of the cavernous internal
carotid artery ( ICA ), a rare
variation: ophthalmic
artery passing through the superior
orbital fissure
Normal OA above upper dural
ring

76. Sympathetic fibres

77. Sympathetic fibres
Within the CS, the sympathetic fi bres are observed mainly in the anterior part of the artery, and
usually they are placed inferiorly. Most of these fi bres run together with V1 (Jittapiromsak et al.
2010 ) . The sympathetic fi bres diverge from the ICAc to adhere to the abducens nerve while
crossing to join the ophthalmic nerve (V1). The main target exit is V1 on the lateral wall of the CS
(Jittapiromsak et al. 2010 ) . Within the CS, the abducens nerve typically courses medially to the
V1 before it exits through the superior orbital fissure.

78. ICAc cavernous portion of the internal carotid artery, lwCS lateral wall of the CS, SF sympathetic fi ber,
IIIcn oculomotor nerve, IVcn trochlear nerve, VIcn abducens nerve, white asterisks branches of the
inferolateral trunk
The largest sympathetic fi ber runs close (within 8 mm) to the ILT, posteroinferiorly and medially located
to it (Zhang et al. 2012 ) . After crossing the superior petrosal sinus the trochlear nerve can pierce the roof
of the cavernous sinus and runs through its lateral wall. The trochlear nerve, within the cavernous sinus,
passes upward the oculomotor nerve (more or less at the level of the optic strut) and becomes the most
superior structure of the CS (Iaconetta et al. 2012). Within the CS course the trochlear nerve is
surrounded by an arachnoidal sheath (Lang 1995 ) and it is always superior to V1.

79. Carotid
1. Paraclival carotid
2. Parasellar carotid

80. Paraclival carotid
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.

81. 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

82. Upper half of paraclival carotid – rostral part, the trigeminal
segment of the paraclival carotid
TG ( Trigeminal ganglion ) is lateral to upper half [ rostral part ] of
Paraclival carotid

83. CR clival recess, ET eustachian tube, ICAc cavernous portion of the internal carotid artery,
ICAh horizontal portion of the internal carotid artery, PAp petrous apex, PLL petrolingual
ligament, VN vidian nerve, V2 second branch of the trigeminal nerve, red arrow artery for
the foramen rotundum, yellow arrow greater petrosal nerve.
The petrolingual ligament connects the petrous apex and the lingula of the sphenoid. It can
be considered the border between the horizontal and cavernous portions of the internal
carotid artery.

84. Endoscopic vision of the suprapetrous window. The dura of the middle cranial fossa has been displaced upward, and
the greater petrosal nerve coming out from the geniculate ganglion is evident. The black arrow in the small picture
indicates the perspective of the vision in the bigger image
ET eustachian tube, GPN greater petrosal nerve, MCFd dura of the middle cranial fossa, MMA
middle meningeal artery, SPS superior petrosal surface, TI trigeminal impression, V3 third
branch of the trigeminal nerve, yellow arrow accessory middle meningeal artery, white asterisks
greater petrosal nerve groove
The skull base given by the sphenoid bone has been drilled away, and the third branch of the trigeminal
nerve and the MMA have been freed from their canals. An accessory MMA is seen in close relationship
to V3. When present, it passes through the foramen ovale.

85. Parasellar carotid
• It covers four segments of the ICA:
1. the hidden segment = Posterior Genu–
most common injure area .
2. the inferior horizontal segment – The inferior
horizontal segment appears short due to the perspective view,
but is the longest segment of the intracavernous ICA.
3. the anterior vertical segment, and
4. the superior horizontal segment ( =
Clinioidal segment )

86. Diameter of parasellar carotid is more than
intracerebral carotid – Prof. Gardner
Add intracerebral carotid photo

87. Cadaveric dissection image demonstrating the close anatomical relationship
of the posterior clinoid (PC) with both the intracranial carotid artery (ICCA)
and the posterior genu of the intracavernous carotid artery (P. CCA). AL,
anterior lobe of the pituitary gland; PL, posterior lobe of the pituitary gland;
BA, basilar artery.
green dotted triangle area for entry
of the endoscope into the interpeduncular fossa

88. Triangles of cavernous sinus

89. 10 Triangles = 4 Cavernous Sinus Triangles + 6 Middle Fossa
Triangles
4 Cavernous Sinus Triangles
1. Clinoidal (Anteromedial) Triangle
2. Oculomotor (Medial or Hakuba's) Triangle
3. Supratrochlear (Paramedian) Triangle
4. Parkinson's (Infratrochlear) Triangle
6 Middle Fossa Triangles
1. Anteromedial (Mullan's) Triangle
2. Anterolateral Triangle
3. Posterolateral (Glasscock's) Triangle
4. Posteromedial (Kawase's) Triangle
5. Inferolateral Triangle
6. Inferomedial Triangle

90. Cavernous Sinus Triangles
1. Clinoidal (Anteromedial) Triangle
· Borders:
1. Optic Nerve
2. Occulomotor Nerve
3. Tentorial Edge
· Contents:
1. Anterior Clinoid Process
2. Clinoidal ICA
2. Oculomotor (Medial or Hakuba's) Triangle
· Borders:
1. Anterior petroclinoid dural fold.
2. Posterior petroclinoid dural fold.
3. Interclinoid dural fold.
· Contents:
1. Occulomotor Nerve
2. Horizontal Segment of ICA

91. Cavernous Sinus Triangles
3. Supratrochlear (Paramedian) Triangle
· Borders:
1. Occulomotor Nerve
2. Trochlear Nerve
3. Tentorial Edge
· Contents:
1. Meningohypophyseal Trunk
4. Parkinson's (Infratrochlear) Triangle
· Borders:
1. Trochelar Nerve
Middle_fossa_triangles
Clinoidal (Anteromedial) Triangle 2
2. Opthalmic Division (V1)
3. Tentorial Edge
· Contents:
1. Cavernous ICA
2. Abducens Nerve

92. For better understanding of 10
triangles click
http://www.slideshare.net/muralich
andnallamothu/10-triangles-360

93. For Other powerpoint presentatioins
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