Summary Brain Stem (Basic Concepts)

Brain Stem (Basic
Concepts)

Part 1
Brainstem is made up of:

midbrain (mesencephalon)

pons (contains the
emergence of the
trigeminal nerve)

medulla oblongata




1st and 2nd cranial nerves are not related to the brain stem



The 3rd to 12th cranial nerves nuclei are present in the
brainstem and their interconnections are located in the
brainstem


pontomedullary sulcus/junction - separates the pons from the
medulla


peduncles - big bundles of white matter that connect brainstem
with the cerebral hemisphere or with the cerebellum




Brain Stem (Basic Concepts) 1

, there are cerebral peduncles and there are cerebellar
peduncles



There are three cerebellar peduncles:

superior - midbrain to cerebellum

middle - pons to cerebellum

inferior - medulla to cerebellum



cerebral peduncles - connect brainstem to the forebrain




Cranial nerves

3rd CN - emerges from upper midbrain
3rd cranial nerve exits from the anterior part of the midbrain
at the level of the superior colliculus.
It is attached to the front of the midbrain emerging from the
medial sides of the cerebral peduncles and then go anteriorly




Brain Stem (Basic Concepts) 2

, interpeduncular fossa - depression between the cerebral
peduncles. When it is full of CSF it is called the
interpeduncular cistern


3rd CN emerges from the medial sides of the cerebral peduncles




Brain Stem (Basic Concepts) 3