Which layer of the dura ends at the foramen magnum?
The periosteal layer ends, the meningeal layer continues
What structures does the SC travel through?
Vertebral foramen of the vertebrae
Where does CSF exist in the spinal column?
In the continued sub-arachnoid space
What is the function of the neural (aka intervertebral) foramen?
Allows spinal nerves to leave the spinal column
What are denticulate ligaments?
Thread-like extensions of the pia mater that project through the arachnoid mater and attach to the dura for lateral stabilization of the SC
What structures creates CSF?
The choroid plexus in each of the ventricles (primarily lateral)
How does CSF get reabsorbed into blood?
Through the arachnoid granulations/villi
What are the 4 functions of CSF?
- Acts as a liquid cushion for the brain
- Provides buoyancy to relieve weight of the brain off the brainstem
- Helps remove metabolites and foreign substances
- Hormone and nutrient transport
Name the condition where too much CSF is accumulated
Hydrocephalus
What structure connects the lateral ventricles to V3?
Interventricular foramen of Monro
Where does V3 sit within the brain?
Between the two sides of the thalamus
What is the “space” in the middle of the third ventricle?
*not actually a space, but appears so on diagrams
The interthalamic adhesions
What structure connects V3 to V4?
Cerebral aqueduct
Where does V4 sit?
Within the brainstem
What structures connect V4 to the sub-arachnoid space?
Foramen of Luschka
How much CSF is generated compared to max capacity?
- Choroid plexus generates ~500cc/day
- System holds ~150cc
- Volume turned over ~3 times/day
What are the flow mechanisms of CSF?
- Pressure created by constant production of CSF
- Pulsation of arteries helps push CSF around
Cisterna Magna: Location and Function
- Above the foramen magnum
- The largest subarachnoid cistern
Lumbar Cistern: Location and Function
- Sits between L1-S2
- A cistern that is a common site for spinal tap/lumbar puncture
Why are spinal taps commonly done from the lumber cistern?
The SC ends above the cistern, so minimal chance of puncturing the cord
What is the order of nerve structures as they leave the SC?
ventral filaments > ventral rootlets > ventral root > spinal nerve
What is the order of nerve structures as they enter the SC?
spinal nerve > dorsal root ganglion > dorsal root > dorsal rootlets
Differentiate the function of ventral and dorsal roots
- ventral = motor
- dorsal = sensory
What structures separate the ventral and lateral columns of the SC?
anterior lateral sulci
