Neuroanatomy

Question 1

filum terminale

Answer 1

• extends from conus medullaris to the posterior surface of the coccyx
• made from pia mater
• anchors the spinal cord

Question 2

Cauda equina

Answer 2

• “Pony tail”
• after birth the vertebral column grows faster than spinal cord
• have to grow axons down to where they can exit (from lateral appeture)

Question 3

Cross section of spinal cord

Answer 3

• white matter peripheral
• grey matter central (butterfly) [opposite to brain]
• anterior median fissure
• posterior median sulcus

Question 4

things that come off the spinal cord

Answer 4

• Dorsal roots = afferent (sensory input)
• ventral root = efferent fibres (motor output)
• combine to make spinal nerve = 2 way info

Question 5

Spinal Cord Injury - where causes what?

Answer 5

• C1-C4 = high tetraplegia (no arms or legs)
• C5-C8 = low tetraplegia (no legs, some arms)
• Thoracic, lumbar or sacral injuries = paraplegia (arms but no legs)

Question 6

Dura mater - function and layers

Answer 6

• provides main protection and support
• in two layers
  
  • periosteal layer (next to the bone)
  • meningeal layer
    
    • folds and extends inwards to for flat partitions
    • subdivide the cranial cavity
    • limit excessive movement of the brain within the cranium
• seperates in places to form venous sinuses (big veins) to drain blood

Question 7

Folding of menigial layers

Answer 7

• forms a partition between:
  
  • two cerebral hemispheres = falx cerebri
  • cerebellum & cerebrum = tentorium cerebelli
  • two cerebellar hemispheres (runs along the midline) = Falx cerebelli

Question 8

space between meningeal dura mater & arachnoid mater

Answer 8

Subdural space
- very narrow, contains a film of fluid
- may be enlarged by bleeding = subdural hemorrhage

Question 9

arachnoid mater

Answer 9

• much more delicate than dura
• doesn’t follow sucli
• connected to the pia mater by fine strands of connective tissue (arachnoid trabecula)

Question 10

Subarchnoid space

Answer 10

• cushion of CSF around the brain
• a barrier between soft brain tissue and hard skull
• contains blood vessels, not super protected
  
  • if severe head knock → bleeding into CSF = subarachnoid haemorrhage

Question 11

Arachnoid villi

Answer 11

• projections of arachnoid matter
• a collection = arachnoid granulations
  
  • cauliflower like structures
  • for draining CSF into venous sinuses

Question 12

Cistern (and the biggest one)

Answer 12

= enlarged subarachnoid space (like in the spaces between brain structures)
biggest = Cisterna Magna (Cerebellomedullary
Cistern)

Question 13

Pia matter

Answer 13

• follows contours of the brain
• surrounds blood vessel
• Helps form the roof of the ventricles, closely associated with choroid plexus and ependyma

Question 14

Spinal meninges - dura

Answer 14

• only the menigenal layer, no periostial layer
• because need more mobility for body
• epidural space between dura and verterbal wall
  
  • Contains fat tissue & venous plexus
  • largest at L2
  • epidural anaesthesia here

Question 15

subarachnoid space - spinal cord

Answer 15

• Between the arachnoid and pia mater meninges
• Contains CSF
• cushions/protects spinal cord

Question 16

Lumbar Cistern

Answer 16

subarachnoid space inferior to spinal cord (below L1)
- Lumbar puncture (sampling of CSF)

Question 17

CSF circulation

Answer 17

chorid plexus → lateral ventricles → 3rd ventricle → cerebral aqueduct → 4th ventricle → median appeture → subarachnoid space → arachnoid vili → superior saggital sinus

Question 18

Occlusion to anterior cerebral artery =

Answer 18

contralateral hemiplegia (one artery) or bilateral
paralysis (two arteries) & impaired sensation
- greatest in lower limb

Question 19

Occlusion to middle cerebral artery =

Answer 19

• a severe contralateral hemiplegia & impaired sensation
  
  • most marked in the upper limb & face
• severe aphasia (if the dominant hemisphere is affected)

Question 20

Occlusion to posterior cerebral artery =

Answer 20

contralateral homonymous hemianopsia

Question 21

describe venous drainage from brain to heart

Answer 21

fine veins in grey matter → pial venous plexuses = associated with pia → cerebral veins drain into sinuses → joined by blood from veins in scalp via emissary veins
→ venous sinuses = large veins (there’s lots of these we need to know → internal jugular vein