59Fig. 4.3 The dural
opening are shown.
Linear dural openings
are made along the floor
of the middle fossa (TD)
as well as in the
presigmoid dura (PFD).
The inset demonstrated
ligation and sectioning
of the superior petrosal
sinus (PS), which allows
subsequent sectioning of
the tentorium and
mobilization of the
sigmoid sinus (SS)
(Reproduced with
permission from
Al-Mefty [ 18 ])
Fig. 4.4 The additional
exposure afforded by
sectioning of the
tentorium and
mobilization of the
sigmoid sinus (SS).
Cranial nerves 3–12 can
be exposed (roman
numerals). The inset
shows the technique of
identifying the fourth
prior to completion of
tentorium division (T) in
order to protect it
(Reproduced with
permission from
Al-Mefty [ 18 ])
4 Posterior and Combined Petrosal Approaches