Brainstem and diencephalon Flashcards
what is the brainstem composed of?
Midbrain
Pons
Medulla
where does the brainstem lie?
In the posterior cranial fossa
What is the brainstem an embryological remnant of?
The mid encephalon and the metencephalon
what are the names of the 2 cavities of the brain stem
IVth ventricle
cerebral aqueduct
Where are the nerves that exit at the pontomedullary junction?
CN VI, VII, VIII
Which of the nerves of the pontomedullary junction has the longest intracranial branch.
What are the potential damages to this?
The abducens nerve.
Can be easily injured due to an increase in intracranial pressure as .
This would lead to Diplopia on medial deviation
Important structures of the medulla and what they do?
Pyramids: site for motor tracts
Olives: point of communication between the motor fibres and the cerebellum
Decussation point: where the motor fibres cross over
Divisions of the medulla on posterior surface
Open: where the central canal opens into the 4th ventricle
Closed: where the CSF cavities are nit surrounded by medulla
What are the middle cerebral peduncles made up of?
centrocipital fibres
where are the superior and inferior colliculi found?
In the midbrain
Important structures of the diencephalon?
- Thalamus
- Hypothalamus
- Mamillary bodies
- Pituitary stalk
- Pineal gland
Position of the cerebellum
- Connected to the brainstem via 3 peduncles
- anterior to the 4th ventricle
- connected to the posterior cranial fossa
Important structures of the cerebellum
- vermis: divides the two hemispheres
- anterior lobe
- posterior lobe
- cerebral tonsils: lie right above the foramen magnum
- Falx cerebelli
- Tentori cerebelli
- flocculonodular lobe
- Primary and posterolateral fissure
What happens when there is a sudden intracranial pressure drop in the cerebellum?
the cerebellar tonisils can descend onto the foramen magnum and cause herniation- cerebral coning
