Interpeduncular fossa
This is the rhomboidal space bounded by the pons, the crura cerebri, and the optic tracts and chiasma. The crura cerebri emerge from the cerebral hemispheres, and are crossed by the optic tracts, which are applied to their lateral surfaces. Inferiorly, the cura descend on the anterior surface of the midbrain and converge into the pons.
Anterior perforated substance
The small area of grey matter forms the roof of the vallecula of the cerebrum, and is pierced by the central branches of the middle and anterior cerebral arteries. It continues laterally as the roof of the stem of the lateral sulcus. Anteriorly, it is bounded by the diverging striae of the olfactory tract; medially, by the optic chiasma and tract and by the diagonal band; posteriorly, by the uncus. The anterior perforated substance is directly continuous,superiorly, with the corpus striatum in the interior of the hemisphe
Lamina terminalis
This this, grey membrane extends superiorly from the optic chiasma, and forms the anterior wall of the third ventricle, the median cavity which separates the two halves of the diencephalon. The lamina terminalis may be seen by bending the optic chiasma gently downward, when the continuity of the lamina terminalis with the anterior perforated substance may be confirmed on both sides.
Superficial attachments of the cranial nerves
Twelve pairs of cranial nerves are attached to the brain, but of these, the second is not a true nerve as it is developed from an outgrowth of the full thickness of the brain tube. and not bythe outgrowth of axons either from cells situated within the central nervous system or withinganglia closely associated with it. The nerve fibres which it contains are, therefore, more akin to a tract than to a peripheral nerve.
- Olfactory.
- Optic.
- Oculonmotor.
- Trochlear.
- Abducent.
- Facial.
- Vestibulocochlear.
- Glossopharyngeal.
- Vagus.
- Hypoglossal.