Flashcards in Week 1 Wet Deck (24)
What section of the skull is the brainstem found in?
The posterior cranial fossa
What embryological vesicles form the brainstem?
Mesencephalon --> Midbrain
Rhombencephalon --> Pons and medulla (& cerebellum)
What ventricles lie in relation to the brainstem?
cerebral aqueduct in the midbrain
IV ventricle posterior to the pons/medulla
Where do the different cranial nerves emerge on the brainstem?
1/2 from cerebrum
3 from midbrain
4 from posterior aspect of midbrain
5 from pons
6, 7 & 8 from pontomedullary junction
9, 10 & 11 from sides of the medulla
12 from medullary pyramids
Which cranial nerves have the longest intracranial course
IV because it emerges posteriorly
What are the main anatomical features of the medulla?
- Decussation of the Pyramids
- Open and closed parts on posterior surface
What is the open part of the medulla?
The posterior superior section where it opens into the 4th ventricle
How is the brainstem connected to the cerebellum?
By 3 cerebeller peduncles, one each from each section of the brainstem.
They contain Centripetal fibres
What are the main anatomical features of the midbrain?
Cerebral peduncles connecting to the thalamus
Superior and inferior colliculi on the post surface
What makes up the diencephalon and where is it found?
Between the cerebrum and the midbrain, it contains the thalamus and hypothalamus
What do we call the visible surface projections of the hypothalamus?
What are the main parts of the cerebellum?
Flocculonodular lobe (V small)
Cerebeller tonsils (At the base by the brainstem)
Vermis (connecting hemispheres)
What happens to the cerebellum during sudden increases in ICP?
The Cerebellar tonsils herniate through the foramen magnum, this is known as coning.
It can compress and damage vital centres in the brainstem resulting in death
What fissure divides cerebral hemispheres?
Longitudinal or Cerebral Fissure
What connects the two cerebral hemispheres?
The corpus collosum
A white matter tract made of Commisural fibres
What are the 3 types of white matter fibres?
Commisural - Connect two hemispheres (e.g. Corpus callosum)
Association - Connect within one hemisphere
Projection - Connect cerebrum to elsewhere (e.g. int capsule)
What do the cerebral hemispheres sit on?
Floor of ant and middle cranial fossae
On the tentorium cerebelli posteriorly
List the 4 main sulci of the cerebral hemispheres?
- Lateral or Sylvian Fissure (Seperates temporal from frontal/parietal)
- Central Sulcus (seperates Fronto-parietal)
- Parieto-occipital sulcus
- Calcarine Sulcus (mainly on medial surface of occipital lobe)
Where are the 4 primary cortex found? (visual, auditory, sensory and motor)
Motor - Pre-central gyrus (frontal lobe)
Sensory - Post-central Gyrus (Parietal Lobe)
Visual - Occipital Lobe
Auditory - Sup Temporal Gyrus
At what level does the spinal cord terminate?
L1/2 in adults
L2/3 in kids
At what level does the dura mater and arachnoid mater terminate?
The pia continues as the filum terminale, attaching to the coccyx
At what level would you perform an LP?
L3/4 in adults or L4/5 in kids
To ensure you enter the cauda equina where theres less risk of nerve damage
How is a patient postitioned for LP?
Foetal position on their left side
This bends the lumbar spine to open up the vertebrae