Basic structure of hair and hair growth cycle.pptx
Skull base 360°- part 1
1. SKULL BASE 360°
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SKULL BASE 360°-Part 1
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SKULL BASE 360°-Part 2
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[ Dated: 26-10-14 ]
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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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4. Below presentation is
SKULL BASE 360°-Part 1
Indetail eloborate description for
each part of skullbase360 done at
www.skullbase360.in
» Presentation by
» Dr. N. Murali Chand DLO MS (ENT) FHM
» Fellowship in HIV medicine, MAMC, New Delhi
» My website = www.integratedmedicine.co.in
• www.skullbase360.in
» Cell= +91 99496 77605
9. 1. External corridor doesn’t matter except cosmesis , only
internal corridor matters – so in Open approaches of skull
base also use endoscope to get best results – see this video
how the Dr. Dugani Suresh ; Neurosurgeon is using
endoscope in Weber Fergusson incision
https://www.youtube.com/watch?v=Y95Jf3u8S8o&feature=y
outu.be
2. Most of the times “Don’t cross the NERVES”
10. Prof. Amin Kassam
CORRIDOR SURGERY
• Video 1
https://www.youtube.com/watch?v=J6ji53nKQy
0
Video 2
https://www.youtube.com/watch?v=56Wt4vQ9
KgE
11. External carotid artery ligation – Note at division of common carotid , external
carotid artery is medial to internal carotid artery – Sometimes the division
may go up very high in neck .
12. Only to lesion lateral to meridian
of pupil in frontal sinus we have
to do osteoplastic flap
The landmarks for canine fossa
puncture/trephine are the
intersection between a vertical line
through the pupil and a horizontal line
drawn through the floor of the nose.
13. Enhanced T1-weighted magnetic resonance imaging (MRI),
coronal section demonstrates a right nasoethmoidal lesion (adenocarcinoma)
with an “hourglass” intradural extension through the ethmoidal
roof. Diffuse enhancement of the dural layer (arrowheads) over
the orbital roof is suspicious for neoplastic spread. The vertical lines limit
the area of the dura safely resectable by a pure endoscopic approach.
15. Illustration of the septal incisions necessary to achieve good access to the entire
anterior wall of the maxillary sinus for
tumors either originating from this region or with a significant anterior wall
attachment. (B) Cadaveric image demonstrating the access to
the anterior wall (AW) of the maxillary sinus with a 70-degree diamond drill (D).
17. (A) The microdebrider blade has been passed through an inferior meatal antrostomy. Note the anterior fulcrum (nasal
vestibule, broken white arrow) and the posterior fulcrum (inferior meatal antrostomy, white arrow). The region of the maxillary
sinus
that can be cleared through this access is shaded. This shaded region is smaller with a middle meatal antrostomy. The single
fulcrum of
the canine fossa puncture is indicated (white arrow) (B,C,D), illustrating how the entire maxillary sinus can be accessed as the
blade
only has a single fulcrum.Medial , posterior & Lateral walls approached through Caldwel-luc
18. The red arrows demonstrate
the endonasal approach, and the green arrows represents the transmaxillary
approach. The blue rectangle shows the parasellar structures.
A more perpendicular angle of attack is achieved in the transmaxillary
approach, and the distance to the target from this route is equal to or
smaller than that in the endonasal approach. Temp.: temporal.
19. Note that in the transmaxillary approach the
structures in the lateral wall of the sphenoid sinus are seen in a
more
perpendicular way, facilitating dissection of this region.
20. Close-up view of the cavernous sinus through the
transmaxillary
approach. Gasser.: gasserian.
21. The pink and orange lines
demonstrate the possible angles of maneuver in transmaxillary
approach.
In green is emphasized the possibilities of resection through
transmaxillary approach.
22. General view of the radial endoscopic accesses to the skull
base --- The green arrows represent the endonasal approaches,
the red arrows represent the transmaxillary
approaches, and the purple arrows represent the
subtemporal approaches. Note the multiple possibilities
of combination of these approaches.
23. Modified denkers approach - Blue dotted line shows
the medial maxillary wall. (B) Panoramic view after removing the medial
maxillary wall. Yellow dotted line shows the connected nasal cavity with maxillary sinus
the maxillary sinus.
24. Schematic demonstrating how the removal of the lateral
aspect of the piriform overture (in the red circle) enables a wider approach
(the green cone compared with the yellow cone) to the lateral
regions (pterygopalatine and infratemporal fossa).
25. Use combination of approaches when ever it is necessary -
Combined Transmastoid Middle Cranial
Fossa Approach
26. Rt lower cranial nerve shwannoma, which approach will be
better ,which approach will be better considering this side is
dominant sinus.
27. Answer
• Amit Keshri says - eight nerve was normal,so was 7th,removed tumor
completely with retrolab approach and to get space,the sigmoid plate was
decompressed and sinus retracted posteriorly after RMSO [ Retro mastoid
sub-occipital ] craniotomy without opening dura posteriorioly.
• Murali Chand Nallamothu For lower cranial nerve schawnnoma POTS
approach is the best - but here you are saying it is dominent sinus , no
need to sacrifice sigmoid sinus -- so in this case we can use extended
translabyrinthine approach for the AFB area part & at carotid canal area
part of the tumor can be removed by externally which is included in the
lower C - shaped incision
• Murali Chand Nallamothu if the 8 th nerve is good we can try
retrolabyrinthinne & retrosigmoid approach & take the help of endoscope.
• Post-op :
28. Posterior wall of maxillary sinus
Periosteum after removal of
posterior bony wall of maxillary
sinus – this periosteum must be
removed in JNA
30. Anteriorly MPP & LPP are fused & posterioly only they are divided .
31. Anteriorly MPP & LPP are fused & posterioly only they are divided .
33. Erosion of right greater wing of
sphenoid in a case of maxillary
carcinoma
35. Medial pterygoid is in line with lateral wall of Sphenoid
-- The superior vertical limb represents the paraclival ascending carotid and the
descending vertical limb is represents the medial pterygoid plate. The horizontal bar of
the ‘H’ is represented by the sphenoid sinus floor.
40. 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 ]
57. Pterygopalatine fossa. A, V2 (blue dotted line) coming out
from the foramen rotundum; B, green-yellow dotted line shows the
pterygopalatine ganglion; C, yellow dotted line shows the vidian
nerve; D, red dotted line shows the sphenopalatine artery; E, light blue
dotted line shows the great palatine nerve; F, white dotted line showing
the infraorbital artery.
63. 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 ]
71. 1. The maxillary artery & Buccal nerve enters the infratemporal fossa between the
superior and inferior head of the
lateral pterygoid muscles.
2. Lingual nerve & Inferior alveolar nerve comes between medial pterygoid & lateral
pterygoid mucles .
76. Triangle formed by temporalis muscle ,
MPM & LPM
Mandibulotomy approach Endospic view
77. Post-maxillectomy “Fat pad” over temporalis muscle – which
is seen as Fat Pad [ FP ] in the triangle formed by temporalis
mucle , MTM & LPM endoscopically
78. Internal carotid artery going medial & posterior to
medial pterygoid muscle into Parapharyngeal space &
becoming Parapharyngeal carotid
79. Internal carotid artery going medial & posterior
to medial pterygoid muscle into Parapharyngeal
space & becoming Parapharyngeal carotid
80. After removing the LPM you will see Tensor veli palatini muscle (TVPM) coming
vertically downwards from anterior surface of ET , protecting parapharyngeal carotid
& after TVPM , thick Stylopharyngeal apneurosis (SPHA ) present ANTERIOR to
Parapharyngeal carotid [ So 2 structures ( TVPM & SPHA ) protecting parapharyngeal
carotid ]
81. After removing the LPM you will see Tensor veli palatini muscle (TVPM) coming
vertically downwards from anterior surface of ET , protecting parapharyngeal carotid
& after TVPM thick Stylopharyngeal apneurosis present ANTERIOR to Parapharyngeal
carotid -- Attached to this ET cartilage [ TP/ET attachment ] is the tensor palatini
(TP) fibrous aponeurosis (solid white line) with its muscle fibers seen below (broken
white line).
82. Hand model --
left hand = medial & lateral pterygoid
right hand = index is parapharyngeal
carotid , middle is IJV , ring is styloid &
stylopharyngeal muscles , thumb is
horizontal carotid
100. Sphenoid osteum present at the juction of upper 2/3rd
& lower 1/3rd junction of Superior turbinate – this
became very useful to me in extensive fungal sinusitis
with polyposis & bleeding.
101. Three sequential indentations are made with the blunt end of the 4-mm
microdebrider blade starting at the medial upper limit of
the posterior bony choana and moving directly superiorly medial to the cut
edge of the superior turbinate.
103. 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. ]
104. The optic strut has two neural-
facing surfaces( yellow dotted
lines) and one vascular-facing
surface (red dotted line).
[ COM – Carotico-Occulomotor
membrane seperates 3rd N from
Clinoidal carotid ]
106. The bone of the anterior clinoid (AC) process
has been left in place, positioned within the
lateral opticocarotid recess.
L-ocr is the space in Optic strut - not
the space in Anterior clinoid process
107. 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
108. In both type a = intradural type,
b = extradural supra-optic strut types Opthalmic
foramen is in Optic canal
109. In Type c = extradural trans-optic strut type , the Opthalmic
foramen in Optic strut
110. L-ocr is the space in Optic strut - not the space
in Anterior clinoid process
Note Optic strut
Note Optic strut
- Right Optic nerve Anterio-superior view
111. Pneumatization of anterior clinoid process – in various planes + onodi cell on
both sides of sphenoid [ when transverse septum present in sphenoid it is
onodi cell ] + sphenoid recess on left side between V2 & VN .
112. The same cadaver photo what you are seeing in CT scan above – Note the supraoptic
pneumatisation [ present in anterior clinoid process ] in an onodi cell .
113. ICAcl clinoidal portion of the internal carotid artery , The clinoidal
segment of the internal carotid artery faces the posterior aspect of the optic
strut [L-OCR ]
114. Red ring – Pneumatization in Optic
strut – which is nothing but L-OCR
116. Sagittal sections and superior views of the sellar region showing the optic nerve and
chiasm, and carotid artery. The prefixed chiasm is located above the tuberculum. The
normal chiasm is located above the diaphragma. The postfixed chiasm is situated
above the dorsum.
117. 1. M-OCR is nothing but Middle Clinoid Process [ indicated by
Green Button in both photos ]
2. M-OCR is the junction point of clinoidal carotid & Supra-
clinoidal carotid
118. The mOCR is located just medial tothe paraclinoidal-supraclinoidal ICA transition and inferior to
the distal cisternal segment of the ON(Labib et al. 2013 ).
Cl clivus, ICAc cavernous portion of the internal carotid artery, ON optic nerve, PG pituitary
gland, PS planum sphenoidale, TS tuberculum sellae, yellow asterisks upper dural ring, blue
arrowheads lower dural ring, white asterisk lateral optico-carotid recess, white circle medial
optico-carotid recess, white arrow ophthalmic artery, black arrows middle clinoid process, red
arrows lateral tubercular crest, yellow arrows endocranial region corresponding to MCP
119. 1. The mOCR is placed at the confluence of the sella, tuberculum sellae, carotid
protuberance, optic canal and planum sphenoidale. The mOCR corresponds to the
lateral extent of the tuberculum sellae. ---- white asterisk lateral opticocarotid recess,
white circle medial opticocarotid recess ---
2. The mOCR is located just medial to the paraclinoidal-supraclinoidal ICA transition
and inferior to the distal cisternal segment of the ON (Labib et al. 2013 ).
120. Limits of the bone resection – Inner ring in below photo
• Posterior ethmoidal arteries
• Medial OCRs
122. Pituitary present between “ four blues”
SIS – superior intercavernous sinus &
IIS – inferior intercavernous sinus
123. 1. Note ASIS & PSIS
2. Note Subarachnoid space at antero-superior area , which is the potential
CSF leak area in pituitary surgery .
Usually the DS originates some
millimeters below the TS.
124. PSIS – Posterior superior intercavernous sinus
ASIS & PSIS together called CIRCULAR SINUS
127. 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).
CS divided into four virtual compartments:
1. medial,
2. lateral,
3. posterosuperior, and
4. anteroinferior
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
riskof injury to the VIth nerve.
131. The 6 linear landmarks of the PCF superimposed on a midsagittal T1-weighted MR
imaging from a patient with CMI: herniation (HR), McRae line (MC), clivus (CL), Twining
line (TW), cerebellum (CR), and supraocciput (SO).
http://www.ajnr.org/content/34/9/1758.figures-
only?cited-by=yes&legid=ajnr;34/9/1758
132. 1. Upper clivus – Upto 6th nerve entry dorello’s canal (petro-clival junction)
2. Middle clivus – from 6th nerve to jugular foramen
3. Lower clivus – from jugular foramen to foramen magnum
134. The middle third (M. 1/3rd) begins at the sella
floor (SF) and extends to the floor of the sphenoid sinus (SSF), and the lower
third (L. 1/3rd) extends from the floor of the sphenoid
sinus to the foramen magnum (FM).
138. In conchal sphenoid surgical landmarks –
1. posterior end of vomer or
keel of sphenoid tells about
the position of pituitary
2. lateral boarder of
posterior choana [ or MPP
]tells about paraclival carotid
& sellar carotid C-SHAPE
convex is lateral to this line
3. posterior lower boarder of
vomer is at the junction of
middle & lower 1/3rd clivus &
it is exactly at foramen
lacerum –my understanding
139. See the relationship between lower boarder of posterior end of vomer &
clivus – vomer lower boarder is at junction of mid & lower clivus – my
understanding
143. The foramen lacerum (FL) is located lateral to the floor of the sphenoid sinus
at the level of the
spheno-petro-clival confuence.
JT jugular tubercle, HC hypoglossal canal –
addFig 3.78 also
145. When we are drilling lower clivus – lateral to
hypoglossal canal we get Jugular fossa
146. Inferior clival line (Fernandez-Miranda et al. 2012 )
The longus capitis and rectus capitis anterior muscle attach on the inferior surface of
the clivus. Below the RCAM the occipito-cervical joint capsule lies. The area of
attachement of the RCAM has been named inferior clival line (Fernandez-Miranda et
al. 2012 ) and correspond to the supracondylar groove (that is a landmark for the
hypoglossal canal).
148. Note CL [ Lower clivus ] in these
photos after drilling of cochlea
149. Note CL [Lower clivus ] in these photos after drilling of cochlea
The clivus bone (CL) can be seen
medial to the internal carotid
artery (ICA). JB Jugular bulb
In the lower part of the approach, the
glossopharyngeal nerve
(IX) can be seen. V Trigeminal nerve, VIII Cochlear
nerve, AICA Anterior
inferior cerebellar artery, CL Clivus bone, DV
Dandy’s vein, FN Facial
nerve, FN(m) Mastoid segment of the facial nerve,
FN(t) Tympanic segment
of the facial nerve, GG Geniculate ganglion, ICA
Internal carotid
artery, JB Jugular bulb, MFD Middle fossa dura, SCA
Superior cerebellar
artery, SS Sigmoid sinus
150. Note CL [Lower clivus ] in these photos
after drilling of cochlea
BT- basal turn of the cochlea Fig. 8.34 The bone medial to the
internal carotid artery (ICA) has been
drilled and the clivus bone (CL) has
been reached. FN Facial nerve,
JB Jugular bulb
151. Note CL [Lower clivus ] in these photos
after drilling of cochlea
Note cochlear aqueduct [ CA ]
Here ICA is vertical part of carotid infront
to cochlea – this is not paraclival carotid
152. Note CL [ clivus ] in these photos after
drilling of cochlea
153. Note CL [Lower clivus ] in these photos
after drilling of cochlea
Note the contralateral vertebral
artery [ CVA ] in below photo
160. V 3 falls like niagara falls from middle cranial fossa to infratemporal
fossa 90 degrees away from V1 & V2 – it is anterior to all the 3
structures , Petrous carotid & ET tube & Parapharyngeal carotid
168. My forceps touched the lingual nerve , posterior to this LN is Inferior
alveolar nerve – These two nerves present in triangle formed by
medial pterygoid , lateral pterygoid & temporalis muscle
173. Sometimes V3 can be seen in the sphenoid sinus
– in “pneumosinus dilatans multiplex”
174. The greater wing of sphenoidal is almost completely pnematised.
So is the temporal bone on the left.the Left carotid can be traced
from the middle ear to the sphenoid - in “pneumosinus dilatans
multiplex”
177. V3[MN] & MMA & ET in lateral & Anterior skull base – see the
relationship of ET tube which is medial to V3 & MMA
179. Posterior boarder of Lateral pterygoid bone
leads to Foramen Ovale [ FO ] – Dr.Kuriakose
180. Posterior boarder of Lateral Pterygoid bone leads to Foramen
Ovale [ FO ] – Dr.Kuriakose
181. Endoscopically [ Anterior skull base ] if we follow upper end of LPT posteriorly we can
reach V3 [ Posterior boarder of Lateral Pterygoid bone leads to Foramen Ovale –
Dr.Kuriakose ]
182. In Infratemporal fossa approach- Posterior boarder of Lateral
pterygoid bone leads to Foramen Ovale [ FO ] – Dr.Kuriakose
183. V3 is anterior (infront) to Horizontal carotid (=
Petrous carotid ) & ET – It cause indentation on the
ET also .
184. In open approaches in maxillary swing approach as long
as you stay lateral to ET you will not injure the
horizontal part of carotid
185. Petrous carotid & paraclival carotid is
SADDLE shape – LEG of the rider is V3
186. V 3 is anteriror to all the 3 structures - Petrous carotid
& ET & Parapharyngeal carotid [ very imp ]
187. Cochlea in anterior skull base
b is cochlea in middle cranial
fossa – cochlear angle between
GSPN & IAC
188. V3 is an important landmark
to locate the post-styloid compartment, as it is anterior
to this space (Falcon et al. 2011 ) .
196. Sinus of Morgagni - In nasopharyngeal carcinoma, the tumor may
extend laterally and involve this sinus involving the Mandibular nerve. This produces a
triad of symptoms known as Trotter's triad [ 1) Conductive deafness ( due to
eustachian tube involvement) 2) Ipsilateral immobility of soft palate 3) Neuralgic pain
in the distribution of V3 ]
203. ET is pointing like an ARROW the posterior genu
of internal carotid [ ICAp & CF is parapharyngeal
carotid ]
204. Sinus of Morgagni - In nasopharyngeal carcinoma, the tumor may
extend laterally and involve this sinus involving the Mandibular nerve. This produces a
triad of symptoms known as Trotter's triad [ 1) Conductive deafness ( due to
eustachian tube involvement) 2) Ipsilateral immobility of soft palate 3) Neuralgic pain
in the distribution of V3 ]
207. black asterisks medial corridor to ICAp – TVPM attached to
anterior surface of ET – so if we go inbetween MPM & TVPM
we reach to ICAp
209. Bony-cartilagenous junction of ET tube is at posterior
genu of carotid - ET is pointing like an ARROW the
posterior genu of internal carotid
210. Yellow arrow - Bony-cartilagenous junction of ET tube is
at posterior genu of carotid - ET is pointing like an
ARROW the posterior genu of internal carotid
211. V 3 is anteriror to all the 3 structures - Petrous carotid
& ET & Parapharyngeal carotid [ very imp ]
214. At bony-cartilagenous junction of ET tube – Horizonal
carotid & Parapharyngeal carotid is above & below ET -
My understanding
215. In open approaches in maxillary swing approach as long
as you stay lateral to ET you will not injure the
horizontal part of carotid
216. Fossa of Rossenmuller apex is laceral carotid [ Foramen Lacerum ]
pharyngeal recess (fossa of Rosenmüller), which projects laterally from the
posterolateral corner of the nasopharynx with its lateral apex facing the internal
carotid artery laterally and the foramen lacerum above;
217. endonasal approaches to expose the
area between the ICAs belong to the sagittal plane, and the
approaches
around the ICA define the coronal plane modules.
218. Note that the eustachian tube indicates the carotid canal only approximately. In other words, it lies on
a different CORONAL plane in respect of the vessel, and from an anterior viewpoint, it covers the vessel for all its
length. -- Medially the space between these two CORONAL planes is nothing but Fossa of Rosenmuller [ My understanding ]
219. Note that the eustachian tube indicates the carotid canal only approximately. In other
words, it lies on
a different CORONAL plane in respect of the vessel, and from an anterior viewpoint, it
covers the vessel for all its
length. -- Medially the space between these two CORONAL planes is nothing but
Fossa of Rosenmuller [ My understanding ]
220. Surgeons should have in mind that the external orifi ce of the carotid canal is not on
the same
coronal plane of the foramen lacerum (anterior genu). It is by far more posteriorly
located.
224. Parts of SOF
1. Lateral part- LFT [ Liver functional tests ] Menumonic – Lacrimal N., Frontal
N.,Trochlear N.
2.Middle part
3. Medial/Inferior part
225. Parts of SOF
1. Lateral part- LFT [ Liver functional tests ] Menumonic – Lacrimal N., Frontal
N.,Trochlear N.
2.Middle part
3. Medial/Inferior part
227. 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.
228. SOF is the space between two Structs – Superiorly OS [
Optic Strut ] & Inferiorly MS [ Maxillary Strut ]
229. SOF is the space between two Structs – Superiorly OS [
Optic Strut ] & Inferiorly MS [ Maxillary Strut ]
230. SOF is the space between two Structs – Superiorly OS [
Optic Strut ] & Inferiorly MS [ Maxillary Strut ]
Anterior view of SOF Posterior view of SOF
233. Yellow line = “nasal” part of SOF
Clinically, the SOF and CS apex
represents a continuum.
234. 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
235. Zonule of zinn - inserts on the infraoptic tubercle, which is often
found as a canal located beneath the optic strut .
244. The bone overlying the internal auditory canal has been removed
and the dura of the canal has been removed near the fundus. The
facial nerve (FN) can be seen entering its labyrinthine segment to form the
geniculate ganglion (GG) more laterally. V Trigeminal nerve, < Acousticofacial
bundle, C Cochlea, ET Eustachian tube, GPN Greater petrosal
nerve, I Incus, IAC Internal auditory canal, ICA Internal carotid artery,
M Malleus, SSC Superior semicircular canal, SV Superior vestibular nerve
Observe the relationship between
GSPN & horizontal carotid
245. Fig. 2.62 The course of the horizontal segment of the internal carotid
artery (ICAh), as seen from the middle cranial fossa of a left temporal
bone. VI Abducent nerve, C Cochlea, GPN Greater petrosal nerve, IAC
Internal auditory canal, ICA(ic) Intracranial internal carotid, M Mandibular
nerve, MMA Middle meningeal artery, MX Maxillary nerve
246. Fig. 5.47 The view after completion of the middle crannial fossa approach. AE Arcuate eminence,
BB Bill’s bar, C Cochlea, FN(iac) Internal auditory canal segment
of the facial nerve, FN(t) Tympanic segment of the facial nerve,
G Geniculate ganglion, GPN Greater petrosal nerve, I Body of the incus,
L Labyrinthine segment of the facial nerve, M Head of the malleus,
MFD Middle fossa dura, SVN Superior vestibular nerve
247. In Infratemporal fossa - Note that the
greater petrosal nerve (GPN) is adherent
to the dura, and that retracting the dura
will lead to stress on the
facial nerve at the geniculate ganglion
(GG) level. Thus, if dural retraction
is needed, cutting the petrosal nerve will
prevent this injury.
In middle cranial fossa – same
point
249. After elevating V3 anterior[infront] to ET & petrous carotid
observe -- GSPN continues as VN [ VN is lateral to paraclival
carotid ]
250. GSPN & GSPN groove in Surpra petrous window
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
251. Vidian nerve is formed by GSPN & Deep petrosal nerve – so GSPN (passes
underneath V3) crosses laterally the Horizontal carotid and paraclival carotid
junction (Prof.Kassam) & continues as Vidian nerve
Blue arrow – LPN &
Yellow arrow – GPN
252. Trans-pterygoid approch-- Vidian Artery present in 60% & enters at the junction of Horizontal
carotid & paraclival carotid – it is present above the Vidian nerve so while drilling vidian canal in
JNA first we have to drill inferior half and then upper half [the bone around the vidian
canal is drilled along its inferior half (from 3 o’clock to 9 o’clock) until the carotid
artery is identified at the lacerum segment ]
253. Vidian nerve - lateral to paraclival carotid &
medial to FO [ Foramen Ovale ]- actually it is
GSPN
254. Vidian canal & Spheno-palatine
foramen are in 90 degrees
261. Axial T2-weighted magnetic resonance imaging (MRI) sequence
at the level of the vidian canal: 1, clivus; 2, pterygoid; 3,
horizontal tract
of the internal carotid artery (ICA); 4, vidian canal.
262. The space between V1 & V 2 and V2 & V3
is sphenoid sinus
Middle cranial fossa approach –
the nerve between V2 & V3 is VN
Anaterior skull base
273. Floor of Lateral recess is by ET ----
BS basisphenoid, ET eustachian tube, LRSS lateral recess of the sphenoid sinus, OPPB orbital
process of the palatine bone, PVA(s) palatovaginal artery(ies), RPm rhinopharyngeal mucosa,
SPAib inferior branch of the sphenopalatine artery, SPPB sphenoidal process of the palatine bone,
SS sphenoid sinus, RS rostrum sphenoidale, VN vidian nerve
275. Surpra petrous window
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
279. The middle fossa retractor is fixed at the petrous
ridge (PR).
AE Arcuate eminence, GPN Greater petrosal
nerve, M Middle meningeal
artery
The expected location of the internal auditory canal
(IAC).
The bar-shaded areas are the locations for drilling. A
Anterior, AE Arcuate
eminence, GPN Greater petrosal nerve, MMA Middle
meningeal
artery, P Posterior
286. 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 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
6th nerve is parallel to V1 – in the
same direction of V1
287. 6th nerve is parallel to V1 – in the same direction of V1
289. 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
291. 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
292. 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
293. Triangles of Middle cranial fossa – see Ant. Medial & Ant. Lateral triangles in both photos.
http://www.eneurosurgery.com/surgicaltrianglesofthecavernoussinus.html
Postero-medial Triangle = KAWASE triangle [Prof.KAWASE , JAPAN Neurosurgeon -below photo]
294. 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
299. KISSING CAROTIDS
1. http://radiopaedia.org/articles/kissing-carotids
2. http://www.ncbi.nlm.nih.gov/pubmed/17607445
• The term kissing carotids refers to
tortuous and elongated vessels which
touch in the midline. They can be be
found in:
• retropharynx 2
• intra-sphenoid 1
– within the pituitary fossa
– within sphenoid sinuses
– within sphenoid bones
• The significance of kissing carotids is
two-fold:
– may mimic intra-sellar pathology
– catastrophic if unknown or unreported
before transsphenoidal / retropharyngeal
surgery
300. Cervical kissing carotids – here also papaphayrngela kinking
present http://www.radrounds.com/photo/cervical-kissing-
carotids-1
Coronal MIP of aberrant medial course
of the carotids arteries showing the
internal carotids arteries nearly
touching at the C2 level.
301. An Aberrant Cervical Internal Carotid Artery in the Mouth
http://amjmed.org/an-aberrant-internal-carotid-artery-in-the-mouth/
302. Intrasellar kissing carotid arteries -This anomaly is particularly
important since it may cause or mimic pituitary disease and also may complicate transsphenoidal
surgery.http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0004-
282X2007000200034&lng=en&nrm=iso&tlng=en
305. kinking or looping of the ICAp - when looping present para-pharyngeal carotid
comes to pre-styloid compartment – previously thought that para-pharyngeal
carotid never comes anterior to styloid mucles – which is UNTRUE
307. The stylopharyngeus and styloglossus
muscles are critical landmarks, being usually placed anterior to the great
vessels (Dallan et al. 2011 ).
Note that the presence of kinking or looping of the ICAp could make this
statement untrue.
308. Cervical kissing carotids – here also papaphayrngela kinking
present http://www.radrounds.com/photo/cervical-kissing-
carotids-1
Coronal MIP of aberrant medial course
of the carotids arteries showing the
internal carotids arteries nearly
touching at the C2 level.
309. An Aberrant Cervical Internal Carotid Artery in the Mouth
http://amjmed.org/an-aberrant-internal-carotid-artery-in-the-mouth/
311. In this kinking of ICA also Prof.Mario
Sanna uses very flexible ICA stents
317. The external carotid artery passes deeply to the digastric and stylohyoid
muscles, but superficially to the stylopharyngeus and styloglossal muscle
when running toward the parotid gland (Janfaza et al. 2001 ) .
324. Endoscopic view of the eustachian tube orifice
(arrow).- Note Internal carotid artery
326. In Infra-temporal fossa approach
The full course of the intratemporal internal carotid artery has
been freed. AFL Anterior foramen lacerum, CF Carotid foramen, CL
Dura
overlying the clivus area, ICA(h) Horizontal segment of the
internal
carotid artery, ICA(v) Vertical segment of the internal carotid
artery,
MN Stump of the mandibular nerve
Drilling of the clivus has been completed. C Basal
turn of the
cochlea (promontory), FN(m) Mastoid segment
of the facial nerve,
FN(t) Tympanic segment of the facial nerve, GG
Geniculate ganglion,
GPN Greater petrosal nerve, ICA Internal carotid
artery, RW Round window
327. Pterygoid trigone – just anterior to foramen lacerum in
both photos is Pterygoid trigone
330. Note that the basal turn of the cochlea (BT) starts to curve
superiorly near the internal carotid artery (ICA), a short distance
from
the level of the round window.
331. In most cases, the medial aspect of the horizontal
portion of the internal carotid
artery is not covered by bone, but simply by dura.
332. GSPN bisects the Petrous carotid & V3 and
Vertical part of Facial nerve bisects Jugular bulb
333. In most cases, the medial aspect of the horizontal
portion of the internal carotid
artery is not covered by bone, but simply by dura.
338. After drilling the carotid canal what we see is endosteal layer ,
not directly the ICA – Dr.Janakiram
Subperiosteal/Subadventitial Dissection
Subperiosteal/subadventitial dissection is accomplished for tumors that involve the ICA to a greater extent,
such as C2 glomus tumors and meningiomas (Fig. 15.24a, b). In general, dissection of the tumor from the
artery is relatively easier and safer in the vertical intrapetrous segment, which is thicker and more accessible
than the horizontal intrapetrous segment. A plane of cleavage between the tumor and the artery should be
found first. In most cases, the tumor is attached to the periosteum surrounding the artery. Dissection is better
started at an area immediately free of tumor. Aggressive tumors may, however, extend even to the adventitia
of the artery and subadventitial dissection may be needed. This should be done very carefully in order to
avoid any tear to the arterial wall, which can become weakened (Fig. 15.25), with the risk of subsequent
blowout.
339. Fig. 15.25 A case of left glomus jugulare tumor in our early experience.
Subadventitial dissection has been performed because the artery had
been so weakened after the tumor removal. Although the patient had no
relevant complications postoperatively, such excessive manipulation is
better avoided and permanent balloon occlusion or stenting are preferably
tried preoperatively.
351. Foramen lacerum - The petrous ICA then curves upward above the
foramen lacerum (FL), thus giving the anterior genu. The segment above the FL is not
truly intrapetrous, and it has been called the lacerum segment by some authors
(Bouthillier et al. 1996 ) . These segments, the anterior genu and the anterior vertical
segment, are placed above the FL, and the artery does not cross the foramen. In this
sense, it is better called the supralacerum segment (Herzallah and Casiano 2007 ) .
Anatomically, the FL is an opening in the dry skull that in life is fi lled by fi
brocartilagineous tissue (fi brocartilago basalis).
AFL = Anterior foramen
lacerum
* [ black asterisk ] = foramen
lacerum
Petrolingual area = foramen
lacerum
353. 1. The foramen lacerum (FL) is located lateral to the floor of the sphenoid sinus at the
level of the spheno-petro-clival confuence.
2. In respect to the FL, the JT is postero-medially located. Therefore to
access the jugular tubercle from anteriorly a complete exposure of the foramen
lacerum is needed.
black asterisk foramen lacerum , JT jugular tubercle, HC hypoglossal canal
356. Parasellar carotid – shrimp shaped
It covers four segments of the ICA: (1) the hidden segment; (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. The
inferior horizontal segment appears short due to the perspective view, but is the longest segment
of the intracavernous ICA. It courses along the sellar floor. The anterior vertical segment
corresponds to the convexity of the C- shaped parasellar protuberance. The superior horizontal
segment includes the clinoidal segment which courses medially to the optic strut, is anchored by
the proximal and distal dural ring and continues in the subarachnoid portion of the vessel.
358. A) Cadaveric dissection image taken within the sphenoid sinus, with removal of bone over the lateral sphenoid wall.
The paraclival carotid artery (PCA) enters the base of the sphenoid sinus and runs in a vertical direction. At
approximately the level of the V2 (maxillary division of trigeminal nerve) the carotid artery then enters the cavernous
sinus and becomes the intracavernous carotid artery (CCA). Once the artery enters the cavernous sinus it continues to
ascend for a short distance, called the vertical portion of the CCA (V. CCA), before turning anteriorly at the posterior
genu of the CCA (P. Genu CCA). This posterior genu corresponds to the floor of the sella. The artery then runs
horizontally as the horizontal portion of the CCA (H. CCA), before reaching the anterior
365. 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
368. Branches of cavernous carotid
1. Meningohypophyseal trunk
2. Inferolateral trunk
The anterior lobe of the pituitary gland is mainly fed by the superior hypophyseal
arteries while the posterior lobe is fed mainly by the inferior hypophyseal artery.
Branches of Intracranial
carotid
1. Superior hypophyseal Artery
370. The anterior lobe of the pituitary gland is mainly fed by the superior
hypophyseal arteries while the posterior lobe is fed mainly by the inferior
hypophyseal artery.
371. Superior Hypophyseal Arteries [ SHAs ]
- more commonly arise from the paraclinoid ICA - In rare cases SHAs originate
from the intracavernous segment of the ICA
374. The MHT is traditionally described as having three branches:
1. the inferior hypophyseal artery, IHA
2. the dorsal meningeal artery (also called the dorsal clival artery) DMA, and
3. the tentorial artery (also called the Bernasconi-Cassinari artery) BCA .
376. At superior part of Siphon carotid , SHA arises where as
inferior part of Siphon carotid MHT [ Inferior
hypophyseal artery ] arises
377. DMA main feeder of dorellos
segement of 6th nerve
DMA main feeder of dorellos
segement of 6th nerve
386. Dural rings – the ICA between upper
& lower dural ring is Clinoidal ICA
387. Cl clivus, ICAc cavernous portion of the internal carotid artery, ON optic nerve, PG pituitary
gland, PS planum sphenoidale, TS tuberculum sellae, yellow asterisks upper dural ring, blue
arrowheads lower dural ring, white asterisk lateral optico-carotid recess, white circle medial
optico-carotid recess, white arrow ophthalmic artery, black arrows middle clinoid process, red
arrows lateral tubercular crest, yellow arrows endocranial region corresponding to MCP
388. Lower dural ring is nothing but COM [ Carotico-occulomotor membrane ] - The dura
lining the inferior aspect of the anterior clinoid process forms the lower
dural ring. This ring is often incomplete on the medial side and often a venous channel
can follow the paraclinoidal ICA to the upper dural ring.
By Fronto temporal approach
389. lower dural ring - This ring is often incomplete on the medial side and often
a venous channel can follow the paraclinoidal ICA to the upper dural ring.
391. 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
394. ICAcl clinoidal portion of the
internal carotid artery , The
clinoidal segment of the internal
carotid artery faces the posterior
aspect of the optic strut.
white arrowhead - paraclinoid
portion of the internal carotid
artery – after removal of
anterior clinoidal process
395. ICA Clin.: clinoid, clinoidal [ Observe here also – posterior border of Optico-
carotid recess is Clinoidal ICA ]
401. The mOCR is located just medial to the paraclinoidal-supraclinoidal ICA
transition and inferior to the distal cisternal segment of the ON(Labib et al. 2013 ).
Cl clivus, ICAc cavernous portion of the internal carotid artery, ON optic nerve, PG pituitary
gland, PS planum sphenoidale, TS tuberculum sellae, yellow asterisks upper dural ring, blue
arrowheads lower dural ring, white asterisk lateral optico-carotid recess, white circle medial
optico-carotid recess, white arrow ophthalmic artery, black arrows middle clinoid process, red
arrows lateral tubercular crest, yellow arrows endocranial region corresponding to MCP
402. 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
403. In the lateral border of the chiasmatic cistern the first part of
the ICAi is visible.
Note Optic tract here which is above
Posterior clinoid process [ PCP ]
416. Surpra petrous window [ see the GSPN groove here ]
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
418. Inferior petrosal sinus is superior to jugular tubercle &
hypoglossal canal is inferior to jugular tubercle
Infratemporal fossa [=intact cochlear
approach – Dr.Morwani ] type B approach
419. The pontomedullary junction.
1. The exit zones of the hypoglossal and abducent nerves are at
the same level [ same vertical line when view from Transclival
approah ( through lower clivus ) ]
2. The abducent nerve exits from the pontomedullary junction, and ascends
in a rostral and lateral direction toward the clivus.
421. In infrapetrous approach there are chances of injury to 6th nerve [ in dorello’s
canal medial to paraclival carotid ] & 12th nerve
422. When we are drilling lower clivus – lateral to
hypoglossal canal we get Jugular fossa
423. Adenoid cycstic carcinoma clivus -- Just look at the carotid. .The paraclival both sides
360 degree encased..look at the mass eroding Petros apex going above horizontal
carotid above the meckels cave..we need a trans cavernous..trans supra Petros. .infra
Petros. . App..
425. Fig. 2.1 Drawing showing the skin incision (red line), the craniotomy
and the microsurgical intraoperative view of the subfrontal
unilateral approach. This approach provides a wide intracranial
exposure of the frontal lobe and easy access to the optic
nerves, the chiasm, the carotid arteries and the anterior communicating
complex
426. Fig. 2.4 Intraoperative microsurgical photograph showing contralateral
extension of the tumor (T) dissected via a unilateral subfrontal
approach. Note on the left side the falx cerebri (F) and
the mesial surface of the left frontal lobe (FL)
427. Fig. 2.5 Drawing showing the skin incision (red line), the craniotomy
and the microsurgical anatomic view of the subfrontal bilateral
route. This approach provides a wide symmetrical anterior
cranial fossa exposure and easy access to the optic nerves, the
chiasm, the carotid arteries and the anterior communicating arteries
complex
428. Supraorbital approach - Fig. 3.2 Illustrations comparing the incision and
bony exposure in a supraorbital craniotomy with those in a pterional craniotomy. a
The supraorbital craniotomy utilizes the subfrontal corridor and involves a frontobasal
burr hole and removal of a small window in the frontal bone. b The pterional
craniotomy utilizes a frontotemporal incision and removal of the frontal and temporal
bones andsphenoid wing. The pterional craniotomy primarily exploits the sylvian
fissure
430. Fig. 4.6 a Craniotomy. b When the flap has been removed the
lesser wing of the sphenoid is drilled down to optimize the most
basal trajectory to the skull base. c Dural opening. DM dura
mater, FL frontal lobe, MMA middle meningeal artery, LWSB
lesser wing of the sphenoid bone, SF sylvian fissure, TL temporal
lobe, TM temporal muscle, ZPFB zygomatic process of the frontal bone
431. Fig. 4.8 Intradural exposure; right approach. Before (a) and after (b) opening of the
Sylvian fissure. A1 first segment of the anterior cerebral artery, AC anterior clinoid, FL
frontal lobe, HA Heubner’s artery, I olfactory tract, III oculomotor nerve, ICA internal
carotid artery, LT lamina terminalis, M1 first segment of the middle cerebral artery,
MPAs perforating arteries, ON optic nerve, P2 second segment of the posterior
cerebral artery, PC posterior clinoid, PcoA posterior communicating artery, SF sylvian
fissure, TL temporal lobe, TS tuberculum sellae
432. Fig. 4.9 Intradural exposure; right approach. a Instruments enlarging the optocarotid
area. b Displacing medially the posterior communicating artery, exposing the
contents of the interpeduncular cistern. AC anterior clinoid, AchA anterior choroidal
artery, BA basilar artery, FL frontal lobe, ICA internal carotid artery, III oculomotor
nerve, OA left ophthalmic artery, ON optic nerve, OT optic tract, P2 second segment of
the posterior cerebral artery, PC posterior clinoid, PcoA posterior communicating
artery, Ps pituitary stalk, SCA superior cerebellar artery, SHA superior hypophyseal
artery, TE tentorial edge, TL temporal lobe
433. Fig. 4.10 Intradural exposure; right approach; enlarged view. A1 first segment of the anterior
cerebral artery, A2 second segment of the anterior cerebral artery, AC anterior clinoid, AcoA
anterior communicating artery, BA basilar artery, FL frontal lobe, HA Heubner’s artery, ICA
internal carotid artery, III oculomotor nerve, LT lamina terminalis, M1 first segment of the middle
cerebral artery, OA left ophthalmic artery, ON optic nerve, P2 second segment of the posterior
cerebral artery, PC posterior clinoid, PcoA posterior communicating artery, SCA superior cerebellar
artery, SHA superior hypophyseal artery, TE tentorial edge, TL temporal lobe, TS tuberculum sellae
434. Fig. 4.11 Intradural exposure; right approach; close-up view ofthe interpeduncular fossa. AchA
anterior choroidal artery, BAbasilar artery, DS dorsum sellae, III oculomotor nerve, IV
trochlear nerve, P1 first segment of the posterior cerebral artery,P2 second segment of the
posterior cerebral artery, PC posteriorclinoid, PcoA posterior communicating artery, Ps pituitary
stalk, SCA superior cerebellar artery, TE tentorial edge
435. Endoscope-assisted microsurgery [ 45° endoscope in a corridor
between the carotid artery and the oculomotor nerve ]-- Fig. 4.12
Intradural exposure; right approach; microsurgical (a) and endoscopic (b–d) views. AchA
anterior choroidal artery, BA basilar artery, C clivus, FL frontal lobe, ICA internal carotid artery, III
oculomotor nerve, ON optic nerve, P1 first segment of the posterior cerebral artery, P2 second
segment of the posterior cerebral artery, PC posterior clinoid, PCA posterior cerebral artery, PcoA
posterior communicating artery, SCA superior cerebellar artery, TE tentorial edge, TL temporal
lobe, Tu thalamoperforating artery; green dotted triangle area for entry of the endoscope into
the interpeduncular fossa
436. Fig. 4.12 Intradural exposure; right approach; microsurgical (a) and endoscopic (b–d) views.
AchA anterior choroidal artery, BA basilar artery, C clivus, FL frontal lobe, ICA internal carotid
artery, III oculomotor nerve, ON optic nerve, P1 first segment of the posterior cerebral artery, P2
second segment of the posterior cerebral artery, PC posterior clinoid, PCA posterior cerebral
artery, PcoA posterior communicating artery, SCA superior cerebellar artery, TE tentorial edge, TL
temporal lobe, Tu thalamoperforating artery; green dotted triangle area for entry of the
endoscope into the interpeduncular fossa
437. Fig. 4.13 Intradural exposure; right approach; microsurgical (a)
and endoscopic omolateral (b) and contralateral (c) views. A1 first segment of the anterior
cerebral artery, AC anterior clinoid, ICA internal carotid artery, FL frontal lobe, III oculomotor
nerve, LT lamina terminalis, M1 first segment of the middle cerebral artery, OA left ophthalmic
artery, ON optic nerve, PcoA posterior communicating artery, SHA superior hypophyseal artery, TE
tentorial edge, TS tuberculum sellae
438. Fig. 4.13 Intradural exposure; right approach; microsurgical (a)
and endoscopic omolateral (b) and contralateral (c) views. A1 first segment of the anterior
cerebral artery, AC anterior clinoid, ICA internal carotid artery, FL frontal lobe, III oculomotor
nerve, LT lamina terminalis, M1 first segment of the middle cerebral artery, OA left ophthalmic
artery, ON optic nerve, PcoA posterior communicating artery, SHA superior hypophyseal artery, TE
tentorial edge, TS tuberculum sellae
443. 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
444. Fig. 4.16 Microsurgical view; intradural anterior clinoidectomy. a, b After the dura above the
anterior clinoid process has been transected in a “T” shape (a), we usually drill always parallel
tothe optic nerve and to the carotid artery (b). c The distal ring is finally exposed. A1
precommunicating anterior cerebral artery, AC anterior clinoid, AchA anterior choroid artery, Ch
optic chiasm, DR distal ring, fl falciform ligament, FL frontal lobe, ICA internal carotid artery, M1
first tract of the middle cerebral artery, ON optic nerve, PC posterior clinoid, PCOA posterior
communicating artery, TS tuberculum sellae
445. Fig. 4.16 Microsurgical view; intradural anterior clinoidectomy. a, b After the dura above the
anterior clinoid process has been transected in a “T” shape (a), we usually drill always parallel
tothe optic nerve and to the carotid artery (b). c The distal ring is finally exposed. A1
precommunicating anterior cerebral artery, AC anterior clinoid, AchA anterior choroid artery, Ch
optic chiasm, DR distal ring, fl falciform ligament, FL frontal lobe, ICA internal carotid artery, M1
first tract of the middle cerebral artery, ON optic nerve, PC posterior clinoid, PCOA posterior
communicating artery, TS tuberculum sellae
450. Fig. 7.13 a Intraoperative photograph shows good exposure of the left tentorial anterior and middle incisura
obtained through the pretemporal and subtemporal corridors. In this patient the
basilar apex is well above the superior margin of the dorsum sellae. b Same patient. A more lateral exposure
showing the pontomesencephalic junction surface and the neurovascular structures in the ambient cistern. c
Intraoperative photograph of another patient showing structures in the left lateral incisural space from the
subtemporal corridor. d Same patient. More lateral view. e Same patient. More posterior exposure. The lifting
of the free edge of the tentorium shows the trochlear nerve entering the tentorium. The junction between the
P2a and P2p segments (P2a, P2p) of the posterior cerebral artery is shown. ACA anterior cerebralartery, AChA
anterior choroidal artery and tiny perforating vessels, BA basilar artery, DS dorsum sellae, FET free edge of
tentorium, ICA internal carotid artery, LM Liliequist’s membrane, LON left optic nerve, ON oculomotor nerve, OT
optic tract, PCA posterior cerebral artery, PComA posterior communicating artery, PLChA posterolateral
choroidal artery arising from the P2a–P2p junction, PS pituitary stalk, RON right optic nerve, SCA superior
cerebellar artery, TN trochlear nerve in the arachnoidal covering
451. Fig. 7.13 a Intraoperative photograph shows good exposure of the left tentorial anterior and middle incisura
obtained through the pretemporal and subtemporal corridors. In this patient the
basilar apex is well above the superior margin of the dorsum sellae. b Same patient. A more lateral exposure
showing the pontomesencephalic junction surface and the neurovascular structures in the ambient cistern. c
Intraoperative photograph of another patient showing structures in the left lateral incisural space from the
subtemporal corridor. d Same patient. More lateral view. e Same patient. More posterior exposure. The lifting
of the free edge of the tentorium shows the trochlear nerve entering the tentorium. The junction between the
P2a and P2p segments (P2a, P2p) of the posterior cerebral artery is shown. ACA anterior cerebral artery, AChA
anterior choroidal artery and tiny perforating vessels, BA basilar artery, DS dorsum sellae, FET free edge of
tentorium, ICA internal carotid artery, LM Liliequist’s membrane, LON left optic nerve, ON oculomotor nerve, OT
optic tract, PCA posterior cerebral artery, PComA posterior communicating artery, PLChA posterolateral
choroidal artery arising from the P2a–P2p junction, PS pituitary stalk, RON right optic nerve, SCA superior
cerebellar artery, TN trochlear nerve in the arachnoidal covering
452. Fig. 7.13 a Intraoperative photograph shows good exposure of the left tentorial anterior and middle incisura
obtained through the pretemporal and subtemporal corridors. In this patient the
basilar apex is well above the superior margin of the dorsum sellae. b Same patient. A more lateral exposure
showing the pontomesencephalic junction surface and the neurovascular structures in the ambient cistern. c
Intraoperative photograph of another patient showing structures in the left lateral incisural space from the
subtemporal corridor. d Same patient. More lateral view. e Same patient. More posterior exposure. The lifting
of the free edge of the tentorium shows the trochlear nerve entering the tentorium. The junction between the
P2a and P2p segments (P2a, P2p) of the posterior cerebral artery is shown. ACA anterior cerebralartery, AChA
anterior choroidal artery and tiny perforating vessels, BA basilar artery, DS dorsum sellae, FET free edge of
tentorium, ICA internal carotid artery, LM Liliequist’s membrane, LON left optic nerve, ON oculomotor nerve, OT
optic tract, PCA posterior cerebral artery, PComA posterior communicating artery, PLChA posterolateral
choroidal artery arising from the P2a–P2p junction, PS pituitary stalk, RON right optic nerve, SCA superior
cerebellar artery, TN trochlear nerve in the arachnoidal covering
453. THE FULLY ENDOSCOPIC SUBTEMPORAL APPROACH [ from
Shahanian book ] - The traditional middle fossa subtemporal approach requires long-
standing placement of retractors on the temporal lobe; therefore, potential injury to the
temporal lobe can occur
(e.g., hematoma and edema resulting in aphasia, hemiparesis, or seizures). This concern should
not be a problem with the described approach because temporal lobe retractors are not used.
(L) a Epidermoid tumor. b Atraumatic
suction. c Brainstem. d Occulomotor (III)
nerve. e Posterior cerebral artery (PCA).
f Superior cerebellar artery (SCA). g
Trochlear (IV) nerve.
(N) a Epidermoid tumor. b Atraumatic suction. c
Left-curved tumor forceps. d Occulomotor (III)
nerve. e Posterior cerebral artery (PCA). f
Posterior communicating (PCOM) artery. g
Superior cerebellar artery (SCA).
h Brainstem. i Trochlear (IV) nerve.
454. Q) a Occulomotor (III) nerve. b
Internal carotid artery (ICA). c
Posterior cerebral artery (PCA).
d Superior cerebellar artery
(SCA).
(P) a Ipsilateral optic (II) nerve. b
Internal carotid artery (ICA). c
Occulomotor (III) nerve.
d Dura overlying anterior clinoid
process.
459. SKULL BASE 360°
Above presentation is
SKULL BASE 360°-Part 1
For
SKULL BASE 360°-Part 2
Please click or copy/paste in URL or weblink area
http://www.slideshare.net/muralichandnallamoth
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[ Dated: 19-4-14 ]
I will update continuosly with date tag at the end as I am getting more
& more information