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
3. For Other powerpoint presentatioins
of
“ Skull base 360° ”
I will update continuosly with date tag at the end as I am
getting more & more information
click
www.skullbase360.in
- you have to login to slideshare.net with Facebook
account for downloading.
14. 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 ]
15.
16. Medial wall of PPF is perpendicular plate of palatine bone –
foramen in it is sphenopalatine foramen
17. foramen rotandum is 5 mm to middle cranial fossa dura
where as vidian nerve from vidial canal to laceral carotid is 2 cm
– listen 4.00 time in this video
https://www.youtube.com/watch?v=Uk57MEgkde8
19. The PPF extended to superior orbital fissure ( SOF ) /
Orbital apex , inferior to the cavernous sinus and
Muller’s muscle. – anterior skull base view
20. The PPF extended to superior orbital fissure ( SOF ) /
Orbital apex , inferior to the cavernous sinus and
Muller’s muscle. – Lateral skull base view
21. The PPF extended to superior orbital fissure ( SOF ) / Orbital
apex , inferior to the cavernous sinus and Muller’s muscle.
Anterior skull base Lateral skull base
24. 1. One line along Vidian nerve & another line along V2
2. Lateral to LPP & infra-orbital nerve [ or V2 ] is Infratemporal fossa
3. One transverse line from Vidian nerve connecting vertical line of V 2 & another
transverse line from V2
4. The space above transverse line of Vidian nerve is Pterygoid Recess of sphenoid
5. The space above transverse line of V2 is Middle cranial fossa ( Meckel’s cave )
25. 1. Pterygoid recess [= sphenoid recess ] is pneumatisation of pterygoid
trigone – spac between V2 & VN [ Vidian nerve ]
2. The space above transverse line of Vidian nerve is Pterygoid Recess
of sphenoid
30. 1. V1,V2,V3 of 5th nerve – V3 is 90° to V1 & V2 and anterior to
petrous carotid like horse rider leg [ V3 ] [ mneumonic ] on saddle
of horse [ petrous carotid & paraclival carotid junction ]
2. Vidian nerve is continuation of GSPN crosses laterally the laceral
carotid
31. V1,V2,V3 of 5th nerve – V3 is 90° to V1 & V2 and anterior to
petrous carotid like horse rider leg [ V3 ] [ mneumonic ] on
saddle of horse [ petrous carotid & paraclival carotid junction ]
32. LPP if you look anteriorly (radiologically ) is in line with FR (V2) , if you look laterally posterior
border of LPP leads to V3 . So when you are removing recurrent nasopharyngeal carcinoma
transnasally you can observe LPP leads to V3 . This V3 seperates pre & post styloid
compartments.
35. In the floor of sphenoid sinus you will get Vidian
nerve when you approach by antero-lateral triangle
36. 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
37. IAN = inferior alveolar nerve , LN = lingual nerve , MPM = medial
pterygoid muscle , LPM = lateral pterygoid muscle
Different layers of
muscles & aponeurosis
protecting great vessels
in infratemporal fossa –
Main protectors are
medial & lateral
pterygoid mucles &
temporalis muscle -
great vessels are
posterior to these 3
muscles –
small contribution of
protection of great
vessels are done by
tensor veli palatini &
styloid muscles &
stylopharyngeal
aponeurosis
44. After drilling LPP & MPP longissmus capitis & superior
constrictor seen .
45. Incision anterior to anterior to anterior
pillar of tonsil for “Trans - Oral
approach to infratemporal fossa”
46. Two planes posterior to MPM which have greater surgical importance ...... …..1. Nasopharyngeal
carcinoma/JNA excision - plane between medial pterygoid muscle ( MPM ) & ET tube/TVPM ( tensor veli
palatini muscle)........ 2 . Trans-oral exposure of Infratemporal fossa (ITF) - incision anterior to anterior pillar
of tonsil - leads to - plane between MPM & superior constrictor / styloid muscles............In the below
diagrams MPM reflected back for understanding purpose
47. Two planes posterior to MPM which have greater surgical importance ...... …..1. Nasopharyngeal
carcinoma/JNA excision - plane between medial pterygoid muscle ( MPM ) & ET tube/TVPM ( tensor veli
palatini muscle)........ 2 . Trans-oral exposure of Infratemporal fossa (ITF) - incision anterior to anterior pillar of
tonsil - leads to - plane between MPM & superior constrictor / styloid muscles............In the below diagrams
MPM reflected back for understanding purpose
48. 1. Each styloid muscle accompanied by one nerve – SPM by 9th nerve ,
SGM by lingual nerve , SHM by 12th nerve
2. SPM & SGM protects ICA whereas SHM protects both ECA & ICA
3. ECA & ICA & CCA are like tuning fork – caricature diagram
49. Each styloid muscle accompanied by one nerve – SPM by 9th
nerve , SGM by lingual nerve , SHM by 12th nerve
50. MPM is reflected back – which shows the structures seen in trans-oral
approach of ITF – incision anterior to anterior pillar of tonsil
54. Schematic diagram for infratemporal fossa approach –
MMA & V3 & pterygoid plate from posterior to anterior
55. V3[MN] & MMA & ET in lateral & Anterior skull base – see the
relationship of ET tube which is medial to V3 & MMA
56. V3 & mma are together
2. V3 accompanied by mma whereas IAN [ inferior
alveolar nerve ] is accompanied by PSAA [ postero-
superior alveolar nerve ]
Lateral skull base Anterior skull base
57. After drilling the tympanic bone & styloid process
inbetween jugular bulb & carotid , 9th nerve is seen
58. Cochlear aqueduct is a pyramidal shape structure present in between
round window & jugular bulb – which is an important landmark for
identification of 9th nerve in retrofacial mastoid air cells area .
61. Superior cervical ganglion is posterior to inferior ganglion of
vagus – SCG lies over prevertebral facia over longus capitis
– below photo left side
67. 12th nerve seen in infra-petrous
approach in anterior skull base
68. 9th & 12th nerves
Anterior skull base Lateral skull base
69. 9th nerve is the most lateral nerve & 12th nerve is most medial nerve in
skull base
70. ITFA with Transcondylar [ = TC ]
Transtubercular [ = TT ] approach
Here Transcondylar is through Occipital Condyle ;
Transtubercular is through Jugular tubercle &
lateral pharyngeal tubercle
71. Endoscopic endonasal view of a cadaveric dissection showing transection of the right eustachian tube (ET)
attachment to foramen lacerum (FL). The hypoglossal nerve (XII) enters the hypoglossal canal just deep to
the ET and separates the occipital condyle (OC) and the jugular tubercle (JT). (BA, basilar artery; ICA,
internal carotid artery [paraclival segment]; IPS, inferior petrosal sinus; VN, vidian nerve.) B. Endoscopic
endonasal view of cadaveric dissection showing the parapharyngeal internal carotid artery (ICA) and
jugular foramen (JF) following transection and removal of the eustachian tube. (BA, basilar artery; IPS,
inferior petrosal sinus; FL, foramen lacerum; JT, jugular tubercle; OC, occipital condyle; XII, hypoglossal
nerve.)
72. Note 12th nerve in between JT ( Jugular tubercle ) & OC
( Occipital condyle ) in both lateral & anterior skull base
Lateral skull base Anterior skull base
73. 1. Laceral carotid & jugular
tubercle & lower cranial
nerves 9th ,10th ,11th are in
the same line .
2. hypoglossal canal present
between occipital
condyle/foramen magnum &
jugular tubercle
74. 1. 9th & 12th nerves crosses parapharyngeal carotid above & below
2. 12th nerves originates medial to apex of parapharyngeal carotid
3. 11th nerve hinges the transverse process of C 1
4. 11 th nerve between vertebral artery & IJV
5. 9th nerve anterior to origin of IPS whereas 10th & 11th nerve posterior to origin of IPS
6. superior ganglion of vagus [ SGV ] is inside the jugular foramen where as inferior ganglion of
vagus [ IGV ] is outside skull base
75. 1. 9th & 12th nerves
crosses parapharyngeal
carotid above & below
2. 12th nerves originates
medial to apex of
parapharyngeal carotid
3. 11th nerve hinges the
transverse process of C 1
4. 11th nerve between
vertebral artery & IJV
5. 9th nerve anterior to
origin of IPS whereas 10th
& 11th nerve posterior to
origin of IPS
6. superior ganglion of
vagus [ SGV ] is inside the
jugular foramen where as
inferior ganglion of vagus
[ IGV ] is outside skull
base
76. Incision anterior to anterior pillar of
tonsil for “Trans - Oral approach of
infratemporal fossa”
77. Incision of trans-oral approach of ITF is – anterior to anterior
pillar of tonsil – pathway is between MPM & superior constrictor
78. 1. Each styloid muscle accompanied by one nerve – SPM by 9th nerve ,
SGM by lingual nerve , SHM by 12th nerve
2. SPM & SGM protects ICA whereas SHM protects both ECA & ICA
3. ECA & ICA & CCA are like tuning fork – caricature diagram
79. Each styloid muscle accompanied by one nerve – SPM by 9th
nerve , SGM by lingual nerve , SHM by 12th nerve
80. MPM is reflected back – which shows the structures seen in trans-oral
approach of ITF – incision anterior to anterior pillar of tonsil
81. Transoral approach to SUPERO-MEDIAL Parapharyngeal
tumors – incision anterior to anterior pillar of tonsil
83. The skin incision is made as
shown.
A cadaveric dissection, showing the
facial nerve trunk (FNT) as
it exits the stylomastoid foramen and
the start of the pes anserinus (PA).
IJV Internal jugular vein, MT Mastoid
tip
84. In a right temporal bone, the intraparotid segment of the
facial
nerve (FNp) has been identified. An extended mastoidectomy
has been
carried out, removing the bony covering of the sigmoid sinus
(SS) and revealing
the posterior fossa and middle fossa dura (MFD).
Skeletonization
of the mastoid and tympanic segments of the facial nerve
(FN) has been
carried out. C Basal turn of the cochlea (promontory), DR
Digastric
ridge, LSC Lateral semicircular canal
The superstructure of the stapes
(S) is being cut using straight
scissors. FN Facial nerve, LSC
Lateral semicircular canal
85. Decompression of the nerve is being carried
out. C Basal turn
of the cochlea (promontory), FN(m)
Mastoid segment of the facial
nerve, FN(t) Tympanic segment of the facial
nerve, G Facial nerve genu,
LSC Lateral semicircular canal, SS Sigmoid
sinus
The mastoid tip (MT) is being removed by
avulsing it posteriorly
away from the stylomastoid foramen (SMF),
to avoid injuring the
nerve at this level. FN(m) Mastoid segment
of the facial nerve, SS Sigmoid
sinus, T Tympanic bone
86. The last shell of bone covering the mastoid (FNm)
and tympanic
(FNt) segments of the facial nerve is now ready to
be removed. The
new fallopian canal (NC) drilled into the root of
the zygoma can be seen.
LSC Lateral semicircular canal, PD Posterior belly
of the digastric muscle,
SMF Stylomastoid foramen, TB Tympanic bone
The last shell of bone covering the
mastoid segment of the facial
nerve (FNm) is being removed. ET
Eustachian tube, FN(p) Intraparotid
facial nerve, G Genu, SM Stylomastoid
foramen, SS Sigmoid
sinus
87. The bony covering of the tympanic
segment of the facial
nerve is being removed. FN(m)
Mastoid segment of the facial nerve,
G Genu, LSC Lateral semicircular
canal, NC New fallopian canal
The bone overlying the proximal part of the
tympanic segment
(FNt) and the geniculate ganglion is being
removed, although the
nerve is not to be rerouted at this level. The
reason for removing bone
here is to prevent it from injuring the rerouted
part of the nerve.
ET Eustachian tube, LSC Lateral semicircular
canal, MFD Middle fossa
dura, NC New fallopian canal
88. A tunnel is being created in the soft tissues
of the parotid
gland (PT) to accommodate the distal part
of the rerouted nerve.
FN(m) Mastoid segment of the facial nerve,
NC New canal, PD Posterior
belly of the digastric muscle, SM
Stylomastoid foramen
A nontoothed forceps is used to hold the soft tissues (ST)
surrounding
the nerve at the level of the stylomastoid foramen
(SMF), and
sharp scissors are used to dissect the soft tissues from
the bone at that
level. C Cochlea, FN(m) Mastoid segment of the facial
nerve, LSC Lateral
semicircular canal, NC New canal, SS Sigmoid sinus
89. The fibrovascular attachments (<)
between the mastoid segment
of the facial nerve (FNm) and the
fallopian canal (FC) should be
sharply cut.
The attachments shown in Fig. 9.14
are being sharply cut to
avoid injuring the mastoid segment
(FNm) of the nerve. FC Fallopian
canal
90. The required length of the facial nerve has been dissected
away from the fallopian canal; the arrows (> <) show the limit.
Keeping
this proximal part of the tympanic segment of the nerve (FNt)
and the
geniculate ganglion attached to the canal medially will help
preserve
part of the blood supply, resulting in better facial nerve
function.
FN(m) Mastoid segment of the facial nerve, LSC Lateral
semicircular
canal, NC New canal
In preparation for rerouting, the soft tissues (ST)
surrounding
the facial nerve at the stylomastoid foramen are being
held by a nontoothed
forceps. FN(m) Mastoid segment of the facial nerve,
FN(p) Intraparotid
facial nerve, FN(t) Tympanic segment of the facial nerve,
NC New canal
91. Rerouting of the facial nerve. FN(m)
Mastoid segment of the
facial nerve, FN(p) Intraparotid facial
nerve, SM Facial nerve at the
stylomastoid
level, ST Soft tissues
The facial nerve has been rerouted into
the new canal (*).
FC Fallopian canal, FN(p) Rerouted part
of the intratemporal facial nerve,
FN(t) Rerouted part of the tympanic
segment of the facial nerve, ST Soft
tissues
92. After the attached muscles have been
dissected away, the
styloid process (SP) is fractured using a
rongeur. FC Fallopian canal,
FN Facial nerve, FN(p) Rerouted part of the
intraparotid facial nerve,
TB Temporal bone
To obtain control over the vascular structures as
they enter
the temporal bone, the tympanic bone (TB), the
fallopian canal remnants
(FC), and the infralabyrinthine air cells are all to
be removed.
C Basal turn of the cochlea (promontory), IJV
Internal jugular vein,
JB Jugular bulb, SS Sigmoid sinus
93. The view after completely uncovering the
lateral surfaces of
the vascular structures. C Basal turn of the
cochlea (promontory), ICA Internal
carotid artery, IJV Internal jugular vein, JB
Jugular bulb, SS Sigmoid
sinus
If further anterior exposure of the internal carotid
artery (ICA)
is required, a retractor is used to keep the
mandibular condyle displaced
anteriorly. C Basal turn of the cochlea
(promontory), FN Rerouted facial
nerve, IJV Internal jugular vein, JB Jugular bulb,
LSC Lateral semicircular
canal, RW Round window, SS Sigmoid sinus
94. The proximal end of the sigmoid
sinus is closed by extraluminal
packing of connective tissue (CT). FN
Rerouted facial nerve, ICA Internal
carotid artery, JB Jugular bulb, MFD
Middle fossa dura, SS Sigmoid
sinus
The lateral wall of the sigmoid
sinus (SS) has been opened.
CT Connective tissue, IJV Internal
jugular vein, L Lumen of the
sigmoid
sinus
95. The distal portion of the opened
sigmoid sinus is packed with
connective tissue (CT). ICA
Internal carotid artery, IJV
Internal jugular
vein, JB Jugular bulb, L Lumen of
the sigmoid sinus
The internal jugular vein (IJV)
is being dissected away. ICA
Internal
carotid artery, JB Jugular bulb
96. The view after removal of the internal jugular
vein and jugular
bulb. Note that in live surgery, the opening of the
inferior petrosal sinus
(IPS) will start bleeding, requiring it to be packed.
IX Hypoglossal nerve,
X Vagus nerve, C Basal turn of the cochlea
(promontory), ICA Internal
carotid artery
The plane of dissection between the
internal carotid artery
(ICA) and the overlying periosteum
(P) is best developed at the entrance
of the artery into its canal. C Basal
turn of the cochlea (promontory)
97. A suction tube is used to displace the
internal carotid artery
(ICA) laterally while the medially lying
bone is being drilled. C Basal turn
of the cochlea (promontory), IPS
Inferior petrosal sinus
The suction tube is used here both to
displace the artery and
to protect it during drilling of the anteriorly
lying bone. ICA(h) horizontal
segment of the internal carotid artery,
ICA(v) vertical segment of the internal
carotid artery
99. Posterolateral (Glasscock's) Triangle approach in
Trans-temporal skull base approaches is called “ Infra-
temporal fossa B approach “ by Prof. Mario sanna
The petrous apex as viewed through the
infratemporal fossa type B approach.
Structures lying lateral to the internal carotid artery
(ICA). The mandibular nerve (V3) and the middle
meningeal artery have been cut. The instrument points
to the position of the already drilled bony
eustachian tube (ET).
100. Iatrogenic chances of injury of cochlea
in infratemporal fossa transpetrous
approach
102. The temporalis muscle is
detached anteriorly.
The zygomatic arch is transected.
Arrows point to the transection sites.
103. Subtotal petrosectomy. The facial nerve (FN) is skeletonized and the
vertical internal carotid artery (ICA) is identified.
104. A minicraniotomy helps positioning
the infratemporal fossa retractor.
Identification of the middle meningeal artery (MMA)
crossing lateral to the eustachian tube (ET).
105. Coagulation of the middle
meningeal artery (MMA).
Cutting the middle meningeal
artery (MMA).
109. The temporalis muscle (TM ) of a left temporal
bone has been
reflected anteriorly after it has been dissected
from the squamous bone
(S). TL Temporalis line, ZR Root of the zygomatic
process
110. The periosteum (P) overlying the
zygomatic arch (ZA) is
being dissected away. This step helps
avoid the laterally lying frontal
branch of the facial nerve. SB
Squamous bone
The view after dissection of the
periosteum (P) from the
zygomatic
arch (ZA). SB Squamous bone, TM
Temporalis muscle
111. The zygomatic arch has been
transected. EAC External auditory
canal, SB Squamous bone, TM
Temporalis muscle, ZR Zygomatic
root
The skin of the external auditory
canal (S) is being dissected
away under the microscope. TM
Tympanic membrane
112. After complete removal of the external
auditory canal skin
and tympanic membrane, the
incudostapedial joint is disarticulated in
order to remove the ossicular chain. C
Chorda tympani, I Incus, M Malleus,
S Stapes
The mastoid cavity and the posterior
and superior walls of the
external auditory canal have been
partially drilled. FB Facial bridge,
FR Facial ridge, MFP Middle fossa
plate, SS Sigmoid sinus
113. A radical mastoidectomy has been carried out, and the facial
nerve has been skeletonized. AR Anterior attic recess, C Basal turn
of the
cochlea (promontory), DR Digastric ridge, FN(m) Mastoid segment
of
the facial nerve, FN(t) Tympanic segment of the facial nerve, LSC
Lateral
semicircular canal, MFP Middle fossa plate, PSC Posterior
semicircular
canal, RW Round window, S Stapes, SS Sigmoid sinus, SSC Superior
semicircular canal, TT Tensor tympani
The retrofacial and infralabyrinthine air cells are
being drilled
using an appropriately sized diamond drill.
Attention must be paid
during this step to avoid injuring the laterally
lying facial nerve with the
burr or the shaft. ELS Endolymphatic sac, FN(m)
Mastoid segment of the
facial nerve, ICA Internal carotid artery, SS
Sigmoid sinus
114. The anterior wall of the external auditory
canal has been partially
drilled, and the vertical segment of the
internal carotid artery (ICA)
has been identified. FN(m) Mastoid
segment of the facial nerve,
FN(t) Tympanic segment of the facial nerve,
JB Jugular bulb, LSC Lateral
semicircular canal, S Stapes, SS Sigmoid
sinus, TT Tensor tympani
Dissecting the articular disk (AD)
of the temporomandibular
joint. ACWAnterior canal wall, SB
Squamous bone, ZR Zygomatic
root
115. A small craniotomy (CT) has
been created in the squamous
bone. ACWAnterior canal wall,
AD Articular disk
A self-retaining retractor is used
to keep the mandible retracted
inferiorly. ACWAnterior canal
wall, AZT Anterior zygomatic
tubercle, GF Glenoid fossa
116. The rest of the anterior canal wall has been
drilled away, and
the internal carotid artery is better
skeletonized. C Basal turn of the
cochlea (promontory), ET Eustachian tube,
FN(m) Mastoid segment of
the facial nerve. G Genu of the internal
carotid artery, ICA(v) Vertical
segment of the internal carotid artery
To obtain control of the horizontal segment
of the internal
carotid artery, the eustachian tube (ET),
glenoid fossa bone (GF), and the
anterior zygomatic tubercle (AZT) have to
be carefully drilled away.
ICA Vertical segment of the internal carotid
artery
117. In live surgery, the middle meningeal
artery (MMA) should be
coagulated to prevent bleeding. ICA
Internal carotid artery, MFP Middle
fossa plate
The middle meningeal artery
(MMA) is being sharply cut.
ET Eustachian tube, ICA Internal
carotid artery, MFP Middle fossa
plate
118. Further anterior drilling uncovers the
mandibular nerve (MN).
This nerve also has to be coagulated
in live surgery before it is cut.
ET Eustachian tube, ICA Internal
carotid artery, MFP Middle fossa
plate
Sharply cutting the mandibular
nerve (MN). ET Eustachian
tube, ICA Internal carotid
artery, MFP Middle fossa plate
119. The stumps of the mandibular
nerve (*). ET Eustachian tube,
ICA Internal carotid artery,
MFP Middle fossa plate
The eustachian tube (ET) and tensor
tympani muscles (TT)
are the last structures lying lateral to the
horizontal segment of the facial
nerve and should be removed. ICA Internal
carotid artery, JB Jugular
bulb, MN The cut end of the mandibular
nerve
120. The lateral, thin part of the
eustachian tube (ET) that remains
can be removed with forceps. C Basal
turn of the cochlea (promontory),
ICA Internal carotid artery, MFP
Middle fossa plate
The tensor tympani muscle has
been dissected away from its
canal (TTC). ET Medial wall of the
eustachian tube, ICA Internal
carotid
artery, MFP Middle fossa plate
121. A large diamond burr is used to remove the remaining
bone
overlying the horizontal segment of the internal carotid
artery. C Basal
turn of the cochlea (promontory), ICA Vertical segment
of the internal
carotid artery, MFP Middle fossa plate, MMA Stump of
the middle
meningeal artery, MN Stump of the mandibular nerve
The horizontal segment of the internal carotid artery
(ICAh)
has been skeletonized. 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. C Basal turn
of the cochlea (promontory), CL Clivus bone, G Genu,
ICA(v) Vertical
segment of the internal carotid artery
122. The tip of the suction is used to displace the internal
carotid
artery (ICA) laterally while the medially lying bone is
being drilled.
C Basal turn of the cochlea (promontory), FN(m) Mastoid
segment of
the facial nerve, FN(t) Tympanic segment of the facial
nerve,
GPN Greater petrosal nerve, MFP Middle fossa plate,
MMA middle
meningeal artery stump
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
123. 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
The view after completion of the
approach.
124. The relationship of the internal carotid artery (ICA) to the
tympanic membrane (TM) and middle ear in a right temporal bone.
A Annulus, FN(m) Mastoid segment of the facial nerve, I Incus, JB Jugular
bulb, LSC Lateral semicircular canal, M Malleus, MFD Middle fossa
dura, PSC Posterior semicircular canal, SSC Superior semicircular canal
125. Infratemporal fossa approach C
ITFA-C
This is an anterior extension of the type B approach, in which
the pterygoid process is drilled, providing control of the nasopharynx,
the pterygopalatine fossa, and the sphenoid sinus
(Fig. 9.18). The approach is designed to give lateral access for
the extirpation of extradural lesions involving the infratemporal
fossa, the nasopharynx, the pterygopalatine fossa, the
sphenoid sinus, and minimal extension into the cavernous
sinus.
126. The sphenoid (SphS) sinus lies
superomedial to the base of
the pterygoid.
The bony anatomy of the base
of the skull. The hatched line
represents the
pharyngobasilar fascia.
127. Cutting the fibrous attachments
of the eustachian tube (ET).
The petro-occipital synchondrosis (arrow) separating the
clivus from the petrous apex.
128. Exposure of the base and lateral
process (PtP) of the pterygoid. Opening the nasopharynx (NP).
129. Locating the sphenoid sinus (SphS).
The maxillary nerve (V2)
runs roughly at the level of the sinus
roof.
Retracting the middle fossa dura
allows complete control of
the horizontal internal carotid artery
(ICA) to the foramen lacerum. AFL,
anterior foramen lacerum.
130. Opening the sphenoid sinus
(SphS).
Cutting the maxillary nerve to
gain access to the lateral wall
of the cavernous sinus.
131. The abducent nerve (VI) crosses
from the medial to the
lateral aspect of the internal
carotid artery (ICA) before
entering the
cavernous sinus.
132. The Group of Preauricular
Transzygomatic Approaches
1. Type D Infratemporal Fossa Approach
2. Preauricular Infratemporal Transzygomatic
Approach
3. Preauricular FTOZ = Frontotemporal
Orbitozygomatic Approach
133. Type D Infratemporal Fossa Approach
Rationale
The type D approach is like the type C but is performed
through a preauricular incision. Mastoidectomy is not
performed and the middle ear is left intact. The
eustachian tube is not sacrificed. The approach is
designed for infratemporal fossa lesions with or without
extension to the pterygopalatine fossa, sphenoid sinus,
and/or minimal cavernous sinus extension; for example,
trigeminal neurinomas with predominant infratemporal
fossa component and minimal middle fossa extension.
The approach will be discussed together with the more
extensive preauricular approaches, namely, the
preauricular infratemporal fossa
134. Preauricular Infratemporal
Transzygomatic Approach
Rationale
The preauricular infratemporal approach is a variant
of theinfratemporal approach in which a large
frontotemporal craniotomy is performed. This
approach is suitable for infratemporal fossa lesions
with or without extension to the petrous apex,
sphenoid sinus, or upper clivus or minimal
cavernous sinus extension. It is suitable for both
intradural and extradural lesions affecting the upper
clivus and parasellar regions. The craniotomy allows
tumor removal with minimal brain retraction.
135. Skin incision.
A semilunar incision (arrows) is
made in the superficial layer of
the deep temporal fascia.
136. The temporalis muscle, zygomatic
arch, and orbital rim are
fully exposed. The temporalis
muscle (TeM) is incised in a line
about 1 cm along its attachment.
Drawing showing the
zygomatic cuts for the pure
transzygomatic approach.
138. Zygomatic and Orbitozygomatic Osteotomy
The zygomatic osteotomy is performed according to the extension of
the lesions as follows:
a) In limited cases, only the zygomatic arch is displaced inferiorly.
The zygomatic bone and the lateral orbital rim are left intact .
b) For the majority of lesions only an “extended” zygomatic
osteotomy is performed in which the zygomatic arch and part of
the zygomatic bone are included in the zygomatic osteotomy . The
orbitozygomatic osteotomy in more advanced cases in which the
tumor extends into the orbital apex through the inferior or
superior orbital fissures: The frontal and temporal dura are
detached from the periorbita exposing the bony orbit.
142. The bone is drilled to the base of
the middle fossa (MFD).
The temporal lobe is retracted for
further bone removal. The
hatched lines represent the bone
that needs to be removed for the
standard orbitozygomatic
osteotomy.
143. With temporal lobe retraction, the three branches of the
trigeminal nerve (V1, V2, V3) are exposed. More exposure can be gained
by further performing the standard orbitozygomatic osteotomy.
145. 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”
146. 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.
147. 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.
149. 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).
150.
151. (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
152. 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.
153. 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.
154. Close-up view of the cavernous sinus through the
transmaxillary
approach. Gasser.: gasserian.
155. 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.
156. 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.
157. 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.
158. 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).
159. Use combination of approaches when ever it is necessary -
Combined Transmastoid Middle Cranial
Fossa Approach
160. Rt lower cranial nerve shwannoma, which approach will be
better ,which approach will be better considering this side is
dominant sinus.
161. 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 :
166. Anteriorly MPP & LPP are fused & posterioly only they are divided .
167. Anteriorly MPP & LPP are fused & posterioly only they are divided .
168.
169.
170. Erosion of right greater wing of
sphenoid in a case of maxillary
carcinoma
171.
172. 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.
177. 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 ]
194. 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.
201. 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 ]
210. 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 .
215. Triangle formed by temporalis muscle ,
MPM & LPM
Mandibulotomy approach Endospic view
216. Post-maxillectomy “Fat pad” over temporalis muscle – which
is seen as Fat Pad [ FP ] in the triangle formed by temporalis
mucle , MTM & LPM endoscopically
217. Internal carotid artery going medial & posterior to
medial pterygoid muscle into Parapharyngeal space &
becoming Parapharyngeal carotid
218. Internal carotid artery going medial & posterior
to medial pterygoid muscle into Parapharyngeal
space & becoming Parapharyngeal carotid
219. 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 ]
220. 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).
221. 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
222. Hypoglossal is just behind the upper end of
parapharyngel carotid – very easy way to
identify 12th nerve in paraphayrngeal space
– Dr.Satish jain
238. Internal carotid artery going medial & posterior to
medial pterygoid muscle into Parapharyngeal space &
becoming Parapharyngeal carotid
239. Internal carotid with aberrant loop lying in the
sagittal plane of the neck.
The normal internal carotid artery runs in a straight
course to the skull base. The pharynx lies anteromedial
and is normally at least 1.5 cm away with fatty areolar
tissue and pharyngeal veins in between. In the
embryo, the internal carotid artery, derived from the
third aortic arch and dorsal aortic root, is normally
coiled. Straightening occurs when the foetal heart and
great vessels descend into the mediastinum. Failure of
or incomplete uncoiling can result in the vessel
assuming a wide loop in the coronal, saggital or, rarely,
transverse plane of the neck .Such an anomaly
is rare but well recognized. This emphasizes the
importance of palpating for pulsating vessels while
undertaking an adenoidectomy. A medialized internal
carotid artery is a well-described entity associated with
velocardiofacial syndrome. In this syndrome, where
pharyngoplasty may be undertaken for velopharyngeal
insufficiency, this internal carotid anomaly is
particularly relevant.
240. Internal carotid with aberrant loop lying in the
coronal plane of the neck. – add pulsating internal carotid
artery video link here
241. Post-styloid compartment = carotid space – contains
last 4 cranial nerves & great vessels & sympathetic
chain
242.
243.
244.
245. PVC – is occupied by Ascending
palatine artery (APA)
246. Transoral approach to SUPERO-MEDIAL Parapharyngeal
tumors – incision anterior to anterior pillar of tonsil
250. The jugular bulb lies beneath the fl oor of the middle ear cavity (Roche et al. 2008 ) . It can be of variable shape and size.
All the lower cranial nerves ( LCNs ) exit the foramen anteromedially to the jugular bulb, separated from it by connective
tissue. The superior ganglion of the vagus nerve is within the jugular foramen ( JF ). At the level of the intraforaminal
course, there is a strict connection between the LCNs. The vagus nerve exits the JF vertically, behind IXcn and ICAp
(Roche et al. 2008 ) and gives its inferior ganglion on the outer skull base surface. The accessory nerve lies immediately
lateral to the vagus nerve.
CR carotid ridge, DM digastric muscle (posterior belly), ICAp parapharyngeal portion of the
internal carotid artery, IJV internal jugular vein, JB jugular bulb, MMA middle meningeal
artery, VIIcn facial nerve, IX glossopharyngeal nerve, X vagus nerve, XI accessory nerve, XII
hypoglossal nerve, black arrow inferior ganglion of vagus nerve
252. Right side. The acousticofacial nerve
bundle, posterior
inferior cerebellar artery, and lower cranial
nerves are seen
in the lower part. The inferior cerebellar
vein (not constant)
enters the jugular bulb. As the posterior
fossa is approached
from behind the sigmoid sinus, the jugular
dural fold appears
as a white linear structure overlying the
lower cranial nerves.
Right side. The acousticofacial nerve
bundle, posterior
inferior cerebellar artery, and lower
cranial nerves are seen
in the lower part. The inferior
cerebellar vein (not constant)
enters the jugular bulb. As the
posterior fossa is approached
from behind the sigmoid sinus, the
jugular dural fold appears
as a white linear structure overlying
the lower cranial nerves.
253. A closer view of the pars nervosa of
the jugular foramen. The
glossopharyngeal nerve has its own
dural porus, which is situated 0-3
mm upwards from the dural
porus of the tenth cranial nerve. The
vagus and the accessory
nerve exit the posterior fossa
together in a sleeve of dura
through the jugular foramen.
Closer view of the inferior area of the left CPA, with
the tip of the endoscope just over the flocculus. The
vagus nerve
(X) and spinal accessory nerve (XI) arise as a widely
separatedseries of rootlets that originate from the lower
medulla and from theupper cervical cord. The rootlets of
the hypoglossal nerve (XII) runhorizontally and are
displaced and stretched by the curved vertebral
artery (VA). The posterior-inferior cerebellar artery (PICA)
arisesfrom the vertebral artery and forms a vascular loop
inferior to the
root exit /entry zone of the acoustic-facial nerve bundle
(VII/ VIII).
254. When they exit from the skull base, the glossopharyngeal nerve is the most lateral,
while the hypoglossal nerve is the most medial. The glossopharyngeal nerve crosses
the internal carotid artery shortly after exiting the skull base.Thehypoglossal nerve
turns inferiorly to run together with the vagus nerve for a short distance in the upper
neck (Fig. 8.4).
255. The glossopharyngeal nerve is seen crossing the internal carotid artery. More inferiorly, the
hypoglossal nerve crosses the artery and passes anteriorly. The vagus nerve is seen coursing
between the internal jugular vein and the internal carotid artery. The accessory nerve crosses
anterolateral to the internal jugular vein and travels posteriorly (Fig. 8.5).
256. In about half the cases, the accessory nerve crosses posteromedial to the internal jugular vein.
In all cases, it passes anterolateral to the transverse process of the atlas. Note the close
relation between the vertebral artery and the internal jugular vein. In
extensive cases of posteriorly located glomus tumors, the vertebral artery may be involved .
257.
258.
259.
260. In infrapetrous approach there are chances of injury to 6th nerve [ in dorello’s
canal medial to paraclival carotid ] & 12th nerve
263. 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
271. 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
276. Sometimes V3 can be seen in the sphenoid sinus
– in “pneumosinus dilatans multiplex”
277. 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”
280. V3[MN] & MMA & ET in lateral & Anterior skull base – see the
relationship of ET tube which is medial to V3 & MMA
281.
282. Posterior boarder of Lateral pterygoid bone
leads to Foramen Ovale [ FO ] – Dr.Kuriakose
283. Posterior boarder of Lateral Pterygoid bone leads to Foramen
Ovale [ FO ] – Dr.Kuriakose
284. 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 ]
View in nasopharyngectomy of
recurrent nasopharyngeal carcinoma
285. In Infratemporal fossa approach- Posterior boarder of Lateral
pterygoid bone leads to Foramen Ovale [ FO ] – Dr.Kuriakose
286. V3 is anterior (infront) to Horizontal carotid (=
Petrous carotid ) & ET – It cause indentation on the
ET also .
287. In open approaches in maxillary swing approach as long
as you stay lateral to ET you will not injure the
horizontal part of carotid
288. Petrous carotid & paraclival carotid is
SADDLE shape – LEG of the rider is V3
289. V 3 is anteriror to all the 3 structures - Petrous carotid
& ET & Parapharyngeal carotid [ very imp ]
290. Cochlea in anterior skull base
b is cochlea in middle cranial
fossa – cochlear angle between
GSPN & IAC
291. 1. V3 is an important landmark to locate the post-styloid compartment, as it
is anterior to this space (Falcon et al. 2011 ) .
2. styloid process & tensor veli palatini seperates pre-styloid & post-styloid
compartments .
299. 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 ]
Add fossa of rosenmullar
diagram photo present in
scott brown text book
306. ET is pointing like an ARROW the posterior genu
of internal carotid [ ICAp & CF is parapharyngeal
carotid ]
307. 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 ]
308.
309.
310. black asterisks medial corridor to ICAp – TVPM attached to
anterior surface of ET – so if we go inbetween MPM & TVPM
we reach to ICAp
311.
312. Bony-cartilagenous junction of ET tube is at posterior
genu of carotid - ET is pointing like an ARROW the
posterior genu of internal carotid
313. 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
314. V 3 is anteriror to all the 3 structures - Petrous carotid
& ET & Parapharyngeal carotid [ very imp ]
317. At bony-cartilagenous junction of ET tube – Horizonal
carotid & Parapharyngeal carotid is above & below ET -
My understanding
318. In open approaches in maxillary swing approach as long
as you stay lateral to ET you will not injure the
horizontal part of carotid
319. 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;
320. 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.
321. 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 ]
322. 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 ]
323. 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.
326. Vidian canal is 2 cm to foramen lacerum – Amin kassam – refer
paolo castelnuovo book , Foramen rotundum is 5mm to dura –
listen 4.00 time in this video
https://www.youtube.com/watch?v=Uk57MEgkde8
327. Gasserian ganglion is intradural – it is not extradural or
intradural – listen 4.00 time in this video
https://www.youtube.com/watch?v=Uk57MEgkde8
329. 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
330. 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
331. 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
332. 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
334. After elevating V3 anterior[infront] to ET & petrous carotid
observe -- GSPN continues as VN [ VN is lateral to paraclival
carotid ]
335. 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
336. 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
337. 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 ]
338. Vidian nerve - lateral to paraclival carotid &
medial to FO [ Foramen Ovale ]- actually it is
GSPN
339. Vidian canal & Spheno-palatine
foramen are in 90 degrees
346. 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.
347. The space between V1 & V 2 and V2 & V3
is sphenoid sinus
Middle cranial fossa approach –
the nerve between V2 & V3 is VN
Anterior skull base
358. 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
359.
360. 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
364. For Other powerpoint presentatioins
of
“ Skull base 360° ”
I will update continuosly with date tag at the end as I am
getting more & more information
click
www.skullbase360.in
- you have to login to slideshare.net with Facebook
account for downloading.
