Using a sharp scalpel and rat-toothed forcep, very carefully
peal away the dura from the middle cranial fossa. Be especially
careful on the upper ridge of the petrous part
of the temporal bone where CN V enters the dura. Try
to follow cranial nerve V into the middle cranial
fossa leaving the ganglion and its three branches intact as seen in
this dissection.
Removing the dura will expose the middle meningeal artery passing through the
foramen spinosum, the
trigeminal (semilunar) ganglion and its divisions such as the
mandibular nerve exiting the foramen ovale and the maxillary nerve
entering the foramen rotundum.
Look for the greater petrosal nerve exiting its
hiatus on the anterior surface of the petrous part of the temporal
bone, but don't be disappointed if you don't see it.
Now turn your attention to the internal carotid artery and peel the
dura away from the cavernous sinus by following the internal carotid
artery into the sinus where it is usually covered with dry venous
blood. Inside the cavernous sinus see if you can find cranial
nerve VI,
which along with the internal carotid artery pass through the cavernous
sinus. The ophthalamic nerve, the maxillary nerve and the oculomotor nerve (CN III)
are located in the lateral wall of
the cavernous sinus. Try to spare these nerves and follow
them into the superior orbital fissure where they enter the orbit.
