Slide 21: Upper Pons (Isthmus)

Identify:

• Pontine Gray (PG)
• Corticospinal Tract Fibers (CST)
• Middle Cerebellar Peduncle (MCP)
• Medial Lemniscus (ML)
• Spinothalamic Tract (STT)
• Lateral Lemniscus (LL)
• Superior Cerebellar Peduncle (SCP)
• Mesencephalic Trigeminal Tract (MesT)
• Central Tegmental Tract (CTT)
• Medial Longitudinal Fasciculus (MLF)
• Raphe Nucleus (R)
• Trochlear Nerve Decussation (4DX)

Note:

• The rostral end of the fourth ventricle has narrowed as it leads to the cerebral aqueduct.
• Notice that the Superior Cerebellar Peduncles are moving toward the midline.