The components of the brainstem include:

1. Diencephalon (thalamus, epithalamus, hypothalamus, subthalamus)
2. Midbrain
3. Pons
4. Medulla oblongata

Structures identifiable on the ventral surface of the brainstem include:

• Optic chiasma, optic tracts.
• Mamilary bodies, infundibulum.
• Crus cerebri, oculomotor nerve attachment.
• Basilar part of pons.
• Pyramids, olivary eminence.

The transition from the medulla to spinal cord characterized by:

• Anterior median fissure appears
• The pyramid disappears
• Reduction in size
• Appearance of spinal nerves

What occurs in the spinomedullary junction histologically?

On the dorsal aspect, the following parts of the brainstem are identifiable:

• Thalamus (with the caudal part, pulvinar overlying part of the midbrain).
• Epithalamus (pineal, habenular, stria medullaris).
• Superior colliculi and brachium.
• Inferior colliculi and brachium.
• Trochlear nerve emerging caudal to inferior colliculi.
• Rhomboid fossa overlying pons/medulla.
• Cuneate and gracile tubercles.